Yoctopuce Amp Yocto-Amp User's guide
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Yocto-Amp, User's guide
Table of contents
1. Introduction
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2. Presentation
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3. Electrocution hazards
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4. Direct current vs. alternating current
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5. First steps
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6. Assembly and connections
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7. Programming, general concepts
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7.4. Current function interface
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7.5. DataLogger function interface
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7.6. What interface: Native, DLL or Service ?
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7.7. Programming, where to start?
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8. Using the Yocto-Amp in command line
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8.3. Control of the Current function
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8.4. Control of the module part
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9. Using Yocto-Amp with Javascript
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9.2. Control of the Current function
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9.3. Control of the module part
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10. Using Yocto-Amp with PHP
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10.2. Control of the Current function
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10.3. Control of the module part
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10.4. HTTP callback API and NAT filters
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11. Using Yocto-Amp with C++
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11.1. Control of the Current function
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11.2. Control of the module part
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11.4. Integration variants for the C++ Yoctopuce library
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12. Using Yocto-Amp with Objective-C
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12.1. Control of the Current function
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12.2. Control of the module part
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13. Using Yocto-Amp with Visual Basic .NET
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13.2. Using the Yoctopuce API in a Visual Basic project
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13.3. Control of the Current function
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13.4. Control of the module part
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14. Using Yocto-Amp with C#
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14.2. Using the Yoctopuce API in a Visual C# project
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14.3. Control of the Current function
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14.4. Control of the module part
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15. Using Yocto-Amp with Delphi
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15.2. Control of the Current function
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15.3. Control of the module part
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16. Using the Yocto-Amp with Python
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16.3. Control of the Current function
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16.4. Control of the module part
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17. Using the Yocto-Amp with Java
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17.2. Control of the Current function
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17.3. Control of the module part
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18. Using the Yocto-Amp with Android
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18.1. Native access and VirtualHub
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18.4. Activating the USB port under Android
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18.5. Control of the Current function
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18.6. Control of the module part
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19. Advanced programming
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20. Using with unsupported languages
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20.4. Porting the high level library
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21. High-level API Reference
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21.2. Module control interface
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21.3. Current function interface
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21.4. DataLogger function interface
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22. Troubleshooting
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22.2. ARM Platforms: HF and EL
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23. Characteristics
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Index
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1. Introduction
The Yocto-Amp module is a 56x20mm module which allows you to measure by USB the current going through an electrical wire, a tool commonly called an ammeter. The Yocto-Amp is able to measure direct current as well as alternating current. Its precision is of 2 mA, 1% for direct current and 5 mA, 3% for alternating current. An important specificity of this module is that it is an isolated ammeter: the part measuring current is electrically isolated from the USB part. This allows you, for instance, to measure the current of the mains without risking to destroy your computer.
The Yocto-Amp module
Yoctopuce thanks you for buying this Yocto-Amp and sincerely hopes that you will be satisfied with it.
The Yoctopuce engineers have put a large amount of effort to ensure that your Yocto-Amp is easy to install anywhere and easy to drive from a maximum of programming languages. If you are nevertheless disappointed with this module, do not hesitate to contact Yoctopuce support
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.
By design, all Yoctopuce modules are driven the same way. Therefore, user's guides for all the modules of the range are very similar. If you have already carefully read through the user's guide of another Yoctopuce module, you can jump directly to the description of the module functions.
1.1. Prerequisites
In order to use your Yocto-Amp module, you should have the following items at hand.
A computer
Yoctopuce modules are intended to be driven by a computer (or possibly an embedded microprocessor). You will write the control software yourself, according to your needs, using the information provided in this manual.
Yoctopuce provides software libraries to drive its modules for the following operating systems:
Windows, Mac OS X, Linux, and Android. Yoctopuce modules do not require installing any specific system driver, as they leverage the standard HID driver
2
provided with every operating system.
www.yoctopuce.com
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1. Introduction
Windows versions currently supported are: Windows XP, Windows 2003, Windows Vista, and
Windows 7. Both 32 bit and 64 bit versions are supported. Yoctopuce is frequently testing its modules on Windows XP and Windows 7.
Mac OS X versions currently supported are: 10.6 (Snow Leopard), Mac OS X 10.7 (Lion), and 10.8
(Mountain Lion). Yoctopuce is frequently testing its modules on Mac OS X 10.6 and 10.7.
Linux kernels currently supported are the 2.6 branch and the 3.0 branch. Other versions of the Linux kernel, and even other UNIX variants, are very likely to work as well, as Linux support is implemented through the standard libusb API. Yoctopuce is frequently testing its modules on Linux kernel 2.6.
Android versions currently supported are: Android 3.1 and later. Moreover, it is necessary for the tablet or phone to support the Host USB mode. Yoctopuce is frequently testing its modules on
Android 4.x on a Nexus 7 and a Samsung Galaxy S3 with the Java for Android library.
A USB cable, type A-micro B
USB connectors exist in three sizes: the "standard" size that you probably use to connect your printer, the very common mini size to connect small devices, and finally the micro size often used to connect mobile phones, as long as they do not exhibit an apple logo. All USB modules manufactured by Yoctopuce use micro size connectors.
The most common USB 2 connectors: A, B, Mini B, Micro A, Micro B.
3
To connect your Yocto-Amp module to a computer, you need a USB cable of type A-micro B. The price of this cable may vary a lot depending on the source, look for it under the name USB A to micro
B Data cable. Make sure not to buy a simple USB charging cable without data connectivity. The correct type of cable is available on the Yoctopuce shop.
You must plug in your Yocto-Amp module with a USB cable of type A - micro B.
If you insert a USB hub between the computer and the Yocto-Amp module, make sure to take into account the USB current limits. If you do not, be prepared to face unstable behaviors and unpredictable failures. You can find more details on this topic in the chapter about assembly and connections.
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Although they existed for some time, Mini A connectors are not available anymore http://www.usb.org/developers/
Deprecation_Announcement_052507.pdf
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1. Introduction
1.2. Optional accessories
The accessories below are not necessary to use the Yocto-Amp module but might be useful depending on your project. These are mostly common products that you can buy from your favourite hacking store. To save you the tedious job of looking for them, most of them are also available on the
Yoctopuce shop.
Screws and spacers
In order to mount the Yocto-Amp module, you can put small screws in the 2.5mm assembly holes, with a screw head no larger than 4.5mm. The best way is to use threaded spacers, which you can then mount wherever you want. You can find more details on this topic in the chapter about assembly and connections.
Micro-USB hub
If you intend to put several Yoctopuce modules in a very small space, you can connect them directly to a micro-USB hub. Yoctopuce builds a USB hub particularly small for this purpose (down to
20mmx36mm), on which you can directly solder a USB cable instead of using a USB plug. For more details, see the micro-USB hub information sheet.
YoctoHub-Ethernet and YoctoHub-Wireless
You can add network connectivity to your Yocto-Amp, thanks to the YoctoHub-Ethernet and the
YoctoHub-Wireless. The YoctoHub-Ethernet provides Ethernet connectivity and the YoctoHub-
Wireless provides WiFi connectivity. Both can drive up to three devices and behave exactly like a regular computer running a VirtualHub.
Enclosures
Your Yocto-Amp has been designed to be installed as is in your project. Nevertheless, Yoctopuce sells enclosures specifically designed for Yoctopuce devices. These enclosures have removable mounting brackets and magnets allowing them to stick on ferromagnetic surfaces. More details are available on the Yoctopuce web site
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. The suggested enclosure model for your Yocto-Amp is the
YoctoBox-Long-Thick-Black-Vents.
You can install your Yocto-Amp in an optional enclosure
4 http://www.yoctopuce.com/EN/products/category/enclosures
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4 www.yoctopuce.com
2. Presentation
1: Micro-B USB socket 4: Measure resistance
2: Yocto-button 5: Measure input (negative)
3: Yocto-led 6: Measure input (positive)
2.1. Common elements
All Yocto-modules share a number of common functionalities.
USB connector
Yoctopuce modules all come with a micro-B USB socket. The corresponding cables are not the most common, but the sockets are the smallest available.
Warning: the USB connector is simply soldered in surface and can be pulled out if the USB plug acts as a lever. In this case, if the tracks stayed in position, the connector can be soldered back with a good iron and using flux to avoid bridges. Alternatively, you can solder a USB cable directly in the
1.27mm-spaced holes near the connector.
Yocto-button
The Yocto-button has two functionalities. First, it can activate the Yocto-beacon mode (see below under Yocto-led). Second, if you plug in a Yocto-module while keeping this button pressed, you can then reprogram its firmware with a new version. Note that there is a simpler UI-based method to update the firmware, but this one works even in case of severely damaged firmware.
Yocto-led
Normally, the Yocto-led is used to indicate that the module is working smoothly. The Yocto-led then emits a low blue light which varies slowly, mimicking breathing. The Yocto-led stops breathing when the module is not communicating any more, as for instance when powered by a USB hub which is disconnected from any active computer.
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2. Presentation
When you press the Yocto-button, the Yocto-led switches to Yocto-beacon mode. It starts flashing faster with a stronger light, in order to facilitate the localization of a module when you have several identical ones. It is indeed possible to trigger off the Yocto-beacon by software, as it is possible to detect by software that a Yocto-beacon is on.
The Yocto-led has a third functionality, which is less pleasant: when the internal software which controls the module encounters a fatal error, the Yocto-led starts emitting an SOS in morse
1
. If this happens, unplug and re-plug the module. If it happens again, check that the module contains the latest version of the firmware, and, if it is the case, contact Yoctopuce support
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.
Current sensor
Each Yocto-module is able to measure its own current consumption on the USB bus. Current supply on a USB bus being quite critical, this functionality can be of great help. You can only view the current consumption of a module by software.
Serial number
Each Yocto-module has a unique serial number assigned to it at the factory. For Yocto-Amp modules, this number starts with YAMPMK01. The module can be software driven using this serial number. The serial number cannot be modified.
Logical name
The logical name is similar to the serial number: it is a supposedly unique character string which allows you to reference your module by software. However, in the opposite of the serial number, the logical name can be modified at will. The benefit is to enable you to build several copies of the same project without needing to modify the driving software. You only need to program the same logical name in each copy. Warning: the behavior of a project becomes unpredictable when it contains several modules with the same logical name and when the driving software tries to access one of these modules through its logical name. When leaving the factory, modules do not have an assigned logical name. It is yours to define.
2.2. Specific elements
The sensor
This sensor is a analogical/digital converter ADS1115IDGST produced by Texas Instruments . Its use does not necessitate any particular precaution, besides those linked to electrocution hazards.
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1 short-short-short long-long-long short-short-short
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3. Electrocution hazards
While the Yocto-Amp module is perfectly able to manage a $SPECMAXVOLT$ voltage, we strongly discourage you to work on a voltage high enough to present risks. Nevertheless, if you decide to override this advice, respect these recommendations, they may well protect you from an embarrassing nomination to the Darwin Awards .
• Use your head, your luck won't last forever.
• Don't work if you are tired. Brilliant decisions taken at 2 a.m. tend to lose their shine at first light.
• Do not work under the influence of euphoriant substances. Beware of family reunions, they are known for their large amount of die-offs among the DIY population.
• Don't work alone. If things go bad, you can then hope to be rescued fast enough.
3.1. Dangerous components
Some components of the Yocto-Amp module find themselves directly on the measured voltage.
Make sure never to touch them when the module is powered on. These components must never be in contact with a conductive component of your project (look out for metallic enclosures). Even more importantly, make sure that your project end user can never touch these components, even accidentally.
Potentially dangerous components of the Yocto-Amp module
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4. Direct current vs. alternating current
The Yocto-Amp module is able to measure a direct current as well as an alternating current. You can typically measure a direct current on the terminals of a battery or at the output of a stabilized power supply for electronic equipment. It is supposed to stay relatively stable over time.
Direct current, stable over time
An alternating current is a current which periodically varies over time. The most typical example is the current of the mains. A dynamo such as the one on your bike produces alternating current as well.
Alternating current, it varies periodically.
Note that an alternating current is not necessarily symmetrical. One can then describe it as the sum of a direct current and of an alternating symmetrical current.
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4. Direct current vs. alternating current
Asymmetrical alternating current. It's the sum of a direct current and an alternating current.
For this reason, the Yocto-Amp provides measures in the shape of a measure of the direct current
(DC) coupled with a measure of the alternating current (AC). When you measure a current with a
Yocto-Amp, several distinct cases can occur:
• A non null DC value and a null AC value: you are measuring a direct current.
• A non null AC value and an almost null DC value: your are measuring a symmetrical alternating current.
• A non null AC value and a non null DC value: you are measuring an asymmetrical alternating current.
• A non null stable DC value and a completely random AC value: the appliance connected to the circuit you are measuring does not have a regular consumption.
The Yocto-Amp has a 2 mA, 1%v accuracy for direct current. However, its accuracy for alternating current is less good: take into account an error of more or less 5 mA, 3% at 50-60hz. Below 30Hz, the lower the frequency is, the less stable the measure is. Above 80Hz, the higher the frequency is, the more underestimated the measure is. Note that the AC measure given by the Yocto-Amp does not correspond to the current peak amplitude, but to the RMS value .
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5. First steps
When reading this chapter, your Yocto-Amp should be connected to your computer, which should have recognized it. It is time to make it work.
Go to the Yoctopuce web site and download the Virtual Hub software
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. It is available for Windows,
Linux, and Mac OS X. Normally, the Virtual Hub software serves as an abstraction layer for languages which cannot access the hardware layers of your computer. However, it also offers a succinct interface to configure your modules and to test their basic functions. You access this interface with a simple web browser
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. Start the Virtual Hub software in a command line, open your preferred web browser and enter the URL http://127.0.0.1:4444. The list of the Yoctopuce modules connected to your computer is displayed.
Module list as displayed in your web bowser.
5.1. Localization
You can then physically localize each of the displayed modules by clicking on the beacon button.
This puts the Yocto-led of the corresponding module in Yocto-beacon mode. It starts flashing, which allows you to easily localize it. The second effect is to display a little blue circle on the screen. You obtain the same behavior when pressing the Yocto-button of the module.
5.2. Test of the module
The first item to check is that your module is working well: click on the serial number corresponding to your module. This displays a window summarizing the properties of your Yocto-Amp.
1 www.yoctopuce.com/EN/virtualhub.php
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The interface was tested on FireFox 3+, IE 6+, Safari, and Chrome. It does not work with Opera.
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5. First steps
Properties of the Yocto-Amp module.
This windows allows you, among other things, to play with your module to check that it is working correctly, as measured values are displayed in real time.
5.3. Configuration
When, in the module list, you click on the configure button corresponding to your module, the configuration window is displayed.
Yocto-Amp module configuration.
Firmware
The module firmware can easily be updated with the help of the interface. To do so, you must beforehand have the adequate firmware on your local disk. Firmware destined for Yoctopuce modules are available as .byn files and can be downloaded from the Yoctopuce web site.
To update a firmware, simply click on the upgrade button on the configuration window and follow the instructions. If the update fails for one reason or another, unplug and re-plug the module and start the update process again. This solves the issue in most cases. If the module was unplugged while it was being reprogrammed, it does probably not work anymore and is not listed in the interface.
However, it is always possible to reprogram the module correctly by using the Virtual Hub software in command line
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.
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3 www.yoctopuce.com/EN/virtualhub.php
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More information available in the virtual hub documentation
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5. First steps
Logical name of the module
The logical name is a name that you choose, which allows you to access your module, in the same way a file name allows you to access its content. A logical name has a maximum length of 19 characters. Authorized characters are
A
..
Z
, a
..
z
,
0
..
9
,
_
, and
-
. If you assign the same logical name to two modules connected to the same computer and you try to access one of them through this logical name, behavior is undetermined: you have no way of knowing which of the two modules answers.
Luminosity
This parameter allows you to act on the maximal intensity of the leds of the module. This enables you, if necessary, to make it a little more discreet, while limiting its power consumption. Note that this parameter acts on all the signposting leds of the module, including the Yocto-led. If you connect a module and no led turns on, it may mean that its luminosity was set to zero.
Logical names of functions
Each Yoctopuce module has a serial number and a logical name. In the same way, each function on each Yoctopuce module has a hardware name and a logical name, the latter can be freely chosen by the user. Using logical names for functions provides a greater flexibility when programming modules.
The two functions provided by the Yocto-Amp module are the "CurrentDC" and "CurrentAC" functions. Simply click on the corresponding "rename" button to assign a new logical name to one of the functions.
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6. Assembly and connections
This chapter provides important information regarding the use of the Yocto-Amp module in real-world situations. Make sure to read it carefully before going too far into your project if you want to avoid pitfalls.
6.1. Fixing
While developing your project, you can simply let the module hang at the end of its cable. Check only that it does not come in contact with any conducting material (such as your tools). When your project is almost at an end, you need to find a way for your modules to stop moving around.
Examples of assembly on supports
The Yocto-Amp module contains 2.5mm assembly holes. You can use these holes for screws. The screw head diameter must not be larger than 4.5mm or they will damage the module circuits. Make sure that the lower surface of the module is not in contact with the support. We recommend using spacers, but other methods are possible. Nothing prevents you from fixing the module with a glue gun; it will not be good-looking, but it will hold.
If your intend to screw your module directly against a conducting part, for example a metallic frame, insert an isolating layer in between. Otherwise you are bound to induce a short circuit: there are naked pads under your module. Simple packaging tape should be enough for electric insulation.
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6. Assembly and connections
6.2. Connections
You must know that the behavior of an ammeter is similar to the behavior of an electrical wire: it merely lets the current go through while measuring it. Therefore, an ammeter must always be connected in series, never in parallel. Always pay great attention to how you connect your Yocto-
Amp. If you connect it in parallel, you are going to create a short circuit, to destroy your Yocto-Amp, to damage your power supply, and you can even start a fire.
Never connect an ammeter in parallel ...
... but in series. This is important.
6.3. Heating
The Yocto-Amp works in letting the current to be measured go through a low value resistance, and in measuring the voltage appearing at the terminals of this resistance. The current going through the resistance heats it, and the more so as the current is stronger. Heating is expected and normal, but your must take it into account in your installation.
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6. Assembly and connections
Heat of the measuring resistance depending on the measured current
6.4. USB power distribution
Although USB means Universal Serial BUS, USB devices are not physically organized as a flat bus but as a tree, using point-to-point connections. This has consequences on power distribution: to make it simple, every USB port must supply power to all devices directly or indirectly connected to it.
And USB puts some limits.
In theory, a USB port provides 100mA, and may provide up to 500mA if available and requested by the device. In the case of a hub without external power supply, 100mA are available for the hub itself, and the hub should distribute no more than 100mA to each of its ports. This is it, and this is not much. In particular, it means that in theory, it is not possible to connect USB devices through two cascaded hubs without external power supply. In order to cascade hubs, it is necessary to use selfpowered USB hubs, that provide a full 500mA to each subport.
In practice, USB would not have been as successful if it was really so picky about power distribution.
As it happens, most USB hub manufacturers have been doing savings by not implementing current limitation on ports: they simply connect the computer power supply to every port, and declare themselves as self-powered hub even when they are taking all their power from the USB bus (in order to prevent any power consumption check in the operating system). This looks a bit dirty, but given the fact that computer USB ports are usually well protected by a hardware current limitation around 2000mA, it actually works in every day life, and seldom makes hardware damage.
What you should remember: if you connect Yoctopuce modules through one, or more, USB hub without external power supply, you have no safe-guard and you depend entirely on your computer manufacturer attention to provide as much current as possible on the USB ports, and to detect overloads before they lead to problems or to hardware damages. When modules are not provided enough current, they may work erratically and create unpredictable bugs. If you want to prevent any risk, do not cascade hubs without external power supply, and do not connect peripherals requiring more than 100mA behind a bus-powered hub.
In order to help controlling and planning overall power consumption for your project, all Yoctopuce modules include a built-in current sensor that tells (with 5mA precision) the consumption of the module on the USB bus.
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7. Programming, general concepts
The Yoctopuce API was designed to be at the same time simple to use and sufficiently generic for the concepts used to be valid for all the modules in the Yoctopuce range, and this in all the available programming languages. Therefore, when you have understood how to drive your Yocto-Amp with your favorite programming language, learning to use another module, even with a different language, will most likely take you only a minimum of time.
7.1. Programming paradigm
The Yoctopuce API is object oriented. However, for simplicity's sake, only the basics of object programming were used. Even if you are not familiar with object programming, it is unlikely that this will be a hinderance for using Yoctopuce products. Note that you will never need to allocate or deallocate an object linked to the Yoctopuce API: it is automatically managed.
There is one class per Yoctopuce function type. The name of these classes always starts with a Y followed by the name of the function, for example YTemperature, YRelay, YPressure, etc.. There is also a YModule class, dedicated to managing the modules themselves, and finally there is the static
YAPI class, that supervises the global workings of the API and manages low level communications.
Structure of the Yoctopuce API.
In the Yoctopuce API, priority was put on the ease of access to the module functions by offering the possibility to make abstractions of the modules implementing them. Therefore, it is quite possible to work with a set of functions without ever knowing exactly which module are hosting them at the hardware level. This tremendously simplifies programming projects with a large number of modules.
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7. Programming, general concepts
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From the programming stand point, your Yocto-Amp is viewed as a module hosting a given number of functions. In the API, these functions are objects which can be found independently, in several ways.
Access to the functions of a module
Access by logical name
Each function can be assigned an arbitrary and persistent logical name: this logical name is stored in the flash memory of the module, even if this module is disconnected. An object corresponding to an
Xxx function to which a logical name has been assigned can then be directly found with this logical name and the YXxx.FindXxx method. Note however that a logical name must be unique among all the connected modules.
Access by enumeration
You can enumerate all the functions of the same type on all the connected modules with the help of the classic enumeration functions FirstXxx and nextXxxx available for each YXxx class.
Access by hardware name
Each module function has a hardware name, assigned at the factory and which cannot be modified.
The functions of a module can also be found directly with this hardware name and the YXxx.FindXxx function of the corresponding class.
Difference between Find and First
The YXxx.FindXxxx and YXxx.FirstXxxx methods do not work exactly the same way. If there is no available module, YXxx.FirstXxxx returns a null value. On the opposite, even if there is no corresponding module, YXxx.FindXxxx returns a valid object, which is not online but which could become so if the corresponding module is later connected.
Function handling
When the object corresponding to a function is found, its methods are available in a classic way.
Note that most of these subfunctions require the module hosting the function to be connected in order to be handled. This is generally not guaranteed, as a USB module can be disconnected after the control software has started. The isOnline method, available in all the classes, is then very helpful.
Access to the modules
Even if it is perfectly possible to build a complete project while making a total abstraction of which function is hosted on which module, the modules themselves are also accessible from the API. In fact, they can be handled in a way quite similar to the functions. They are assigned a serial number at the factory which allows you to find the corresponding object with YModule.Find(). You can also assign arbitrary logical names to the modules to make finding them easier. Finally, the YModule class contains the YModule.FirstModule() and nextModule() enumeration methods allowing you to list the connected modules.
Functions/Module interaction
From the API standpoint, the modules and their functions are strongly uncorrelated by design.
Nevertheless, the API provides the possibility to go from one to the other. Thus, the get_module() method, available for each function class, allows you to find the object corresponding to the module hosting this function. Inversely, the YModule class provides several methods allowing you to enumerate the functions available on a module.
7.2. The Yocto-Amp module
The Yocto-Amp module provides a two instances of the Current function. The current1
input corresponds to the DC current component, while the current2
input corresponds to the AC current component (RMS). The typical accuracy of the DC measure is 2 mA or 1 per cent, while the precision of the AC measure is 5 mA or 3 per cent, for frequencies between 30Hz and 80Hz.
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7. Programming, general concepts
module : Module attribute
productName
type
String
modifiable ?
read-only serialNumber logicalName
String
String read-only modifiable
Hexadecimal number read-only productId productRelease firmwareRelease persistentSettings
Hexadecimal number read-only
String read-only
Enumerated modifiable luminosity beacon upTime usbCurrent rebootCountdown usbBandwidth
0..100%
On/Off
Time
Used current (mA)
Integer
Enumerated modifiable modifiable read-only read-only modifiable modifiable
current1 : Current current2 : Current attribute
logicalName
type
String
modifiable ?
modifiable advertisedValue unit currentValue
String
String read-only read-only
Floating-point number read-only lowestValue highestValue
Floating-point number modifiable
Floating-point number modifiable currentRawValue
Floating-point number read-only logFrequency
Frequency reportFrequency
Frequency calibrationParam
16 bit word array modifiable modifiable modifiable resolution
Floating-point number modifiable
dataLogger : DataLogger attribute
logicalName advertisedValue currentRunIndex timeUTC recording autoStart clearHistory
type
String
String
Integer
UTC time
On/Off
On/Off
Boolean
modifiable ?
modifiable read-only read-only modifiable modifiable modifiable modifiable
7.3. Module control interface
This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.
productName
Character string containing the commercial name of the module, as set by the factory.
serialNumber
Character string containing the serial number, unique and programmed at the factory. For a Yocto-
Amp module, this serial number always starts with YAMPMK01. You can use the serial number to access a given module by software.
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21
7. Programming, general concepts
22
logicalName
Character string containing the logical name of the module, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access a given module. If two modules with the same logical name are in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among
A
..
Z
, a
..
z
,
0
..
9
,
_
, and
-
.
productId
USB device identifier of the module, preprogrammed to 31 at the factory.
productRelease
Release number of the module hardware, preprogrammed at the factory.
firmwareRelease
Release version of the embedded firmware, changes each time the embedded software is updated.
persistentSettings
State of persistent module settings: loaded from flash memory, modified by the user or saved to flash memory.
luminosity
Lighting strength of the informative leds (e.g. the Yocto-Led) contained in the module. It is an integer value which varies between 0 (leds turned off) and 100 (maximum led intensity). The default value is
50. To change the strength of the module leds, or to turn them off completely, you only need to change this value.
beacon
Activity of the localization beacon of the module.
upTime
Time elapsed since the last time the module was powered on.
usbCurrent
Current consumed by the module on the USB bus, in milli-amps.
rebootCountdown
Countdown to use for triggering a reboot of the module.
usbBandwidth
Number of USB interfaces used by the device. If this parameter is set to DOUBLE, the device can send twice as much data, but this may saturate the USB hub. Remember to call the saveToFlash
()
method and then to reboot the module to apply this setting.
7.4. Current function interface
The Yoctopuce application programming interface allows you to read an instant measure of the sensor, as well as the minimal and maximal values observed.
logicalName
Character string containing the logical name of the current sensor, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the current sensor directly. If two current sensors with the same logical name are used in the same
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7. Programming, general concepts
project, there is no way to determine which one answers when one tries accessing by logical name.
The logical name is limited to 19 characters among
A
..
Z
, a
..
z
,
0
..
9
,
_
, and
-
.
advertisedValue
Short character string summarizing the current state of the current sensor, that is automatically advertised up to the parent hub. For a current sensor, the advertised value is the measured value.
unit
Short character string representing the measuring unit for the measured value.
currentValue
Current in mA, as a floating point number.
lowestValue
Minimal current observed, as a floating point number.
highestValue
Maximal current observed, as a floating point number.
logFrequency
Datalogger recording frequency, or "OFF" when measures should not be stored in the data logger flash memory.
reportFrequency
Timed value notification frequency, or "OFF" when timed value notifications are disabled for this function.
calibrationParam
Extra calibration parameters (for instance to compensate for the effects of an enclosure), as an array of 16 bit words.
resolution
Measure resolution (i.e. precision of the numeric representation, not necessarily of the measure itself).
7.5. DataLogger function interface
Yoctopuce sensors include a non-volatile memory capable of storing ongoing measured data automatically, without requiring a permanent connection to a computer. The DataLogger function controls the global parameters of the internal data logger.
logicalName
Character string containing the logical name of the data logger, initially empty. This attribute can be modified at will by the user. Once initialized to an non-empty value, it can be used to access the data logger directly. If two data loggers with the same logical name are used in the same project, there is no way to determine which one answers when one tries accessing by logical name. The logical name is limited to 19 characters among
A
..
Z
, a
..
z
,
0
..
9
,
_
, and
-
.
advertisedValue
Short character string summarizing the current state of the data logger, that is automatically advertised up to the parent hub. For a data logger, the advertised value is its recording state (ON or
OFF).
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23
7. Programming, general concepts
currentRunIndex
Current run number, corresponding to the number of time the module was powered on with the dataLogger enabled at some point.
timeUTC
Current UTC time, in case it is desirable to bind an absolute time reference to the data stored by the data logger. This time must be set up by software.
recording
Activation state of the data logger. The data logger can be enabled and disabled at will, using this attribute, but its state on power on is determined by the autoStart persistent attribute.
autoStart
Automatic start of the data logger on power on. Setting this attribute ensures that the data logger is always turned on when the device is powered up, without need for a software command.
clearHistory
Attribute that can be set to true to clear recorded data.
7.6. What interface: Native, DLL or Service ?
There are several methods to control you Yoctopuce module by software.
Native control
In this case, the software driving your project is compiled directly with a library which provides control of the modules. Objectively, it is the simplest and most elegant solution for the end user. The end user then only needs to plug the USB cable and run your software for everything to work.
Unfortunately, this method is not always available or even possible.
24
The application uses the native library to control the locally connected module
Native control by DLL
Here, the main part of the code controlling the modules is located in a DLL. The software is compiled with a small library which provides control of the DLL. It is the fastest method to code module support in a given language. Indeed, the "useful" part of the control code is located in the DLL which is the same for all languages: the effort to support a new language is limited to coding the small library which controls the DLL. From the end user stand point, there are few differences: one must simply make sure that the DLL is installed on the end user's computer at the same time as the main software.
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7. Programming, general concepts
The application uses the DLL to natively control the locally connected module
Control by service
Some languages do simply not allow you to easily gain access to the hardware layers of the machine. It is the case for Javascript, for instance. To deal with this case, Yoctopuce provides a solution in the form of a small piece of software called Virtual Hub
1
. It can access the modules, and your application only needs to use a library which offers all necessary functions to control the modules via this virtual hub. The end users will have to start the virtual hub before running the project control software itself, unless they decide to install the hub as a service/deamon, in which case the virtual hub starts automatically when the machine starts up.
The application connects itself to the virtual hub to gain access to the module
The service control method comes with a non-negligible advantage: the application does not need to run on the machine on which the modules are connected. The application can very well be located on another machine which connects itself to the service to drive the modules. Moreover, the native libraries and DLL mentioned above are also able to connect themselves remotely to one or several virtual hubs.
1 www.yoctopuce.com/EN/virtualhub.php
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25
7. Programming, general concepts
When a virtual hub is used, the control application does not need to reside on the same machine as the module.
Whatever the selected programming language and the control paradigm used, programming itself stays strictly identical. From one language to another, functions bear exactly the same name, and have the same parameters. The only differences are linked to the constraints of the languages themselves.
Language
C++
Objective-C
Delphi
Python
VisualBasic .Net
C# .Net
Javascript
Node.js
PHP
Native Native with DLL Virtual hub
-
•
•
-
-
-
-
-
-
-
-
-
•
•
•
•
•
Java
Java for Android
-
• -
-
Command line • -
Support methods for different languages
•
•
•
•
•
•
•
•
•
•
•
•
Limitations of the Yoctopuce libraries
Natives et DLL libraries have a technical limitation. On the same computer, you cannot concurrently run several applications accessing Yoctopuce devices directly. If you want to run several projects on the same computer, make sure your control applications use Yoctopuce devices through a
VirtualHub software. The modification is trivial: it is just a matter of parameter change in the yRegisterHub()
call.
7.7. Programming, where to start?
At this point of the user's guide, you should know the main theoretical points of your Yocto-Amp. It is now time to practice. You must download the Yoctopuce library for your favorite programming language from the Yoctopuce web site
2
. Then skip directly to the chapter corresponding to the chosen programming language.
All the examples described in this guide are available in the programming libraries. For some languages, the libraries also include some complete graphical applications, with their source code.
When you have mastered the basic programming of your module, you can turn to the chapter on advanced programming that describes some techniques that will help you make the most of your
Yocto-Amp.
26
2 http://www.yoctopuce.com/EN/libraries.php
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7. Programming, general concepts www.yoctopuce.com
27
28 www.yoctopuce.com
8. Using the Yocto-Amp in command line
When you want to perform a punctual operation on your Yocto-Amp, such as reading a value, assigning a logical name, and so on, you can obviously use the Virtual Hub, but there is a simpler, faster, and more efficient method: the command line API.
The command line API is a set of executables, one by type of functionality offered by the range of
Yoctopuce products. These executables are provided pre-compiled for all the Yoctopuce officially supported platforms/OS. Naturally, the executable sources are also provided
1
.
8.1. Installing
Download the command line API
2
. You do not need to run any setup, simply copy the executables corresponding to your platform/OS in a directory of your choice. You may add this directory to your
PATH variable to be able to access these executables from anywhere. You are all set, you only need to connect your Yocto-Amp, open a shell, and start working by typing for example:
C:\> YCurrent any get_currentValue
To use the command API on Linux, you need either have root privileges or to define an udev rule for your system. See the Troubleshooting chapter for more details.
8.2. Use: general description
All the command line API executables work on the same principle. They must be called the following way
C:\> Executable [options] [target] command [ parameter ]
[options]
manage the global workings of the commands, they allow you, for instance, to pilot a module remotely through the network, or to force the module to save its configuration after executing the command.
[target]
is the name of the module or of the function to which the command applies. Some very generic commands do not need a target. You can also use the aliases "any" and "all", or a list of names separated by comas without space.
1
If you want to recompile the command line API, you also need the C++ API.
2 http://www.yoctopuce.com/EN/libraries.php
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29
8. Using the Yocto-Amp in command line
command
is the command you want to run. Almost all the functions available in the classic programming APIs are available as commands. You need to respect neither the case nor the underlined characters in the command name.
[parameters]
logically are the parameters needed by the command.
At any time, the command line API executables can provide a rather detailed help. Use for instance:
C:\> executable
/help
to know the list of available commands for a given command line API executable, or even:
C:\> executable command
/help
to obtain a detailed description of the parameters of a command.
8.3. Control of the Current function
To control the Current function of your Yocto-Amp, you need the YCurrent executable file.
For instance, you can launch:
C:\> YCurrent any get_currentValue
This example uses the "any" target to indicate that we want to work on the first Current function found among all those available on the connected Yoctopuce modules when running. This prevents you from having to know the exact names of your function and of your module.
But you can use logical names as well, as long as you have configured them beforehand. Let us imagine a Yocto-Amp module with the YAMPMK01-123456 serial number which you have called
"MyModule", and its current1 function which you have renamed "MyFunction". The five following calls are strictly equivalent (as long as MyFunction is defined only once, to avoid any ambiguity).
C:\> YCurrent YAMPMK01-123456.current1 describe
C:\> YCurrent YAMPMK01-123456.MyFunction describe
C:\> YCurrent MyModule.current1 describe
C:\> YCurrent MyModule.MyFunction describe
C:\> YCurrent MyFunction describe
To work on all the Current functions at the same time, use the "all" target.
C:\> YCurrent all describe
For more details on the possibilities of the
YCurrent
executable, use:
C:\> YCurrent
/help
8.4. Control of the module part
Each module can be controlled in a similar way with the help of the example, to obtain the list of all the connected modules, use:
YModule
executable. For
30
C:\> YModule inventory
You can also use the following command to obtain an even more detailed list of the connected modules:
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8. Using the Yocto-Amp in command line
C:\> YModule all describe
Each xxx
property of the module can be obtained thanks to a command of the get_xxxx()
type, and the properties which are not read only can be modified with the example: set_xxx()
command. For
C:\> YModule YAMPMK01-12346 set_logicalName MonPremierModule
C:\> YModule YAMPMK01-12346 get_logicalName
Changing the settings of the module
When you want to change the settings of a module, simply use the corresponding set_xxx command. However, this change happens only in the module RAM: if the module restarts, the changes are lost. To store them permanently, you must tell the module to save its current configuration in its nonvolatile memory. To do so, use the saveToFlash
command. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash
method.
For example:
C:\> YModule YAMPMK01-12346 set_logicalName MonPremierModule
C:\> YModule YAMPMK01-12346 saveToFlash
Note that you can do the same thing in a single command with the
-s
option.
C:\> YModule -s YAMPMK01-12346 set_logicalName MonPremierModule
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
8.5. Limitations
The command line API has the same limitation than the other APIs: there can be only one application at a given time which can access the modules natively. By default, the command line API works in native mode.
You can easily work around this limitation by using a Virtual Hub: run the VirtualHub
3 concerned machine, and use the executables of the command line API with the example, if you use:
-r
on the
option. For
C:\> YModule inventory you obtain a list of the modules connected by USB, using a native access. If another command which accesses the modules natively is already running, this does not work. But if you run a Virtual Hub, and you give your command in the form:
C:\> YModule -r 127.0.0.1 inventory it works because the command is not executed natively anymore, but through the Virtual Hub. Note that the Virtual Hub counts as a native application.
3 http://www.yoctopuce.com/EN/virtualhub.php
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31
32 www.yoctopuce.com
9. Using Yocto-Amp with Javascript
Javascript is probably not the first language that comes to mind to control hardware, but its ease of use is a great advantage: with Javascript, you only need a text editor and a web browser to realize your first tests.
At the time of writing, the Javascript library functions with any recent browser ... except Opera. It is likely that Opera will end up working with the Yoctopuce library one of these days
1
, but it is not the case right now.
Javascript is one of those languages which do not allow you to directly access the hardware layers of your computer. Therefore you need to run the Yoctopuce TCP/IP to USB gateway, named
VirtualHub, on the machine on which your modules are connected.
9.1. Getting ready
Go to the Yoctopuce web site and download the following items:
• The Javascript programming library
2
• The VirtualHub software
3
for Windows, Mac OS X or Linux, depending on your OS
Decompress the library files in a folder of your choice, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.
9.2. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a JavaScript code snipplet to use the Current function.
<SCRIPT type= "text/javascript" src= "yocto_api.js" ></SCRIPT>
<SCRIPT type= "text/javascript" src= "yocto_current.js" ></SCRIPT>
// Get access to your device, through the VirtualHub running locally
yRegisterHub ( 'http://127.0.0.1:4444/' ) ; var current = yFindCurrent ( "YAMPMK01-123456.current1" ) ;
// Check that the module is online to handle hot-plug
if( current.
isOnline ())
1
Actually, as soon as Opera implements support for the HTTP Access-Control-Allow-Origin header.
2 www.yoctopuce.com/EN/libraries.php
3 www.yoctopuce.com/EN/virtualhub.php
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33
9. Using Yocto-Amp with Javascript
{
// Use current.get_currentValue(), ...
}
Let us look at these lines in more details.
yocto_api.js and yocto_current.js
These two Javascript includes provide access to functions allowing you to manage Yoctopuce modules. yocto_api.js
must always be included, yocto_current.js
manage modules containing a current sensor, such as Yocto-Amp.
is necessary to
yRegisterHub
The yRegisterHub
function allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the
127.0.0.1:4444
address indicates the local machine, port
4444
(the standard port used by
Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running.
yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
var current = yFindCurrent ( "YAMPMK01-123456.current1" ) ; var current = yFindCurrent ( "YAMPMK01-123456.MyFunction" ) ; var current = yFindCurrent ( "MyModule.current1" ) ; var current = yFindCurrent ( "MyModule.MyFunction" ) ; var current = yFindCurrent ( "MyFunction" ) ; yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by yFindCurrent
allows you to know if the corresponding module is present and in working order.
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Open your preferred text editor
4
, copy the code sample below, save it in the same directory as the
Yoctopuce library files and then use your preferred web browser to access this page. The code is also provided in the directory Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
The example is coded to be used either from a web server, or directly by opening the file on the local machine. Note that this latest solution does not work with some versions of Internet Explorer, in particular IE 9 on Windows 7, which is not able to open network connections when working on a local file. In order to use Internet Explorer, you should load the example from a web server. No such problem exists with Chrome, Firefox or Safari.
34
4
If you do not have a text editor, use Notepad rather than Microsoft Word.
www.yoctopuce.com
9. Using Yocto-Amp with Javascript
If your Yocto-Amp is not connected on the host running the browser, replace in the example the address
127.0.0.1
by the IP address of the host on which the Yocto-Amp is connected and where you run the VirtualHub.
<HTML>
<HEAD>
<TITLE>Hello World</TITLE>
<SCRIPT type= "text/javascript" src= "yocto_api.js" ></SCRIPT>
<SCRIPT type= "text/javascript" src= "yocto_current.js" ></SCRIPT>
<SCRIPT language= 'javascript1.5' type= 'text/JavaScript' >
<!--
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ) != YAPI_SUCCESS ) { alert ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
} function refresh ()
{ var sensor,sensorAC,sensorDC; var serial = document .
getElementById ( 'serial' ) .
value ; if( serial == '' ) {
// or use any connected module suitable for the demo
sensor = yFirstCurrent () ; if( sensor ) {
serial = sensor.
module () .
get_serialNumber () ; document .
getElementById ( 'serial' ) .
value = serial;
}
}
sensorDC = yFindCurrent ( serial+ ".current1" ) ;
sensorAC = yFindCurrent ( serial+ ".current2" ) ; if ( sensorDC.
isOnline ()) { document .
getElementById ( 'msg' ) .
value = '' ; document .
getElementById ( "DC" ) .
value = sensorDC.
get_currentValue () ; document .
getElementById ( "AC" ) .
value = sensorAC.
get_currentValue () ;
} else { document .
getElementById ( 'msg' ) .
value = 'Module not connected' ;
} setTimeout ( 'refresh()' , 500 ) ;
}
-->
</SCRIPT>
</HEAD>
<BODY onload= 'refresh();' >
Module to use: <input id= 'serial' >
<input id= 'msg' style= 'color:red;border:none;' readonly><br>
DC: <input id= 'DC' size= 5 readonly>mA<br>
AC: <input id= 'AC' size= 5 readonly>mA
</BODY>
</HTML>
9.3. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
<HTML>
<HEAD>
<TITLE>Module Control</TITLE>
<SCRIPT type= "text/javascript" src= "yocto_api.js" ></SCRIPT>
<SCRIPT language= 'javascript1.5' type= 'text/JavaScript' >
<!--
// Use explicit error handling rather than exceptions
yDisableExceptions () ;
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ) != YAPI_SUCCESS ) { alert ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
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35
9. Using Yocto-Amp with Javascript
36
} var module; function refresh ()
{ var serial = document .
getElementById ( 'serial' ) .
value ; if( serial == '' ) {
// Detect any conected module suitable for the demo
module = yFirstModule () .
nextModule () ; if( module ) {
serial = module.
get_serialNumber () ; document .
getElementById ( 'serial' ) .
value = serial;
}
}
module = yFindModule ( serial ) ; if( module.
isOnline ()) { document .
getElementById ( 'msg' ) .
value = '' ; var html = 'serial: ' +module.
get_serialNumber () + '<br>' ;
html += 'logical name: ' +module.
get_logicalName () + '<br>' ;
html += 'luminosity:' +module.
get_luminosity () + '%<br>' ;
html += 'beacon:' ; if ( module.
get_beacon () ==Y_BEACON_ON )
html+= "ON <a href='javascript:beacon(Y_BEACON_OFF)'>switch off</a><br>" ; else
html+= "OFF <a href='javascript:beacon(Y_BEACON_ON)'>switch on</a><br>" ;
html += 'upTime: ' + parseInt ( module.
get_upTime () / 1000 ) + ' sec<br>' ;
html += 'USB current: ' +module.
get_usbCurrent () + ' mA<br>' ;
html += 'logs:<br><pre>' +module.
get_lastLogs () + '</pre><br>' ; document .
getElementById ( 'data' ) .
innerHTML = html;
} else { document .
getElementById ( 'msg' ) .
value = 'Module not connected' ;
} setTimeout ( 'refresh()' , 1000 ) ;
} function beacon ( state )
{
module.
set_beacon ( state ) ;
refresh () ;
}
-->
</SCRIPT>
</HEAD>
<BODY onload= 'refresh();' >
Module to use: <input id= 'serial' >
<input id= 'msg' style= 'color:red;border:none;' readonly><br>
<span id= 'data' ></span>
</BODY>
</HTML>
Each property xxx
of the module can be read thanks to a method of type properties which are not read-only can be modified with the help of the get_xxxx() set_xxx()
, and
method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx()
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash()
method. The short example below allows you to modify the logical name of a module.
<HTML>
<HEAD>
<TITLE>Change module settings</TITLE>
<SCRIPT type= "text/javascript" src= "yocto_api.js" ></SCRIPT>
<SCRIPT language= 'javascript1.5' type= 'text/JavaScript' >
<!--
// Use explicit error handling rather than exceptions
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9. Using Yocto-Amp with Javascript
yDisableExceptions () ;
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ) != YAPI_SUCCESS ) { alert ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
} var module; function refresh ()
{ var serial = document .
getElementById ( 'serial' ) .
value ; if( serial == '' ) {
// Detect any conected module suitable for the demo
module = yFirstModule () .
nextModule () ; if( module ) {
serial = module.
get_serialNumber () ; document .
getElementById ( 'serial' ) .
value = serial;
}
}
module = yFindModule ( serial ) ; if( module.
isOnline ()) { document .
getElementById ( 'msg' ) .
value = '' ; document .
getElementById ( 'curName' ) .
value = module.
get_logicalName () ;
} else { document .
getElementById ( 'msg' ) .
value = 'Module not connected' ;
} setTimeout ( 'refresh()' , 1000 ) ;
} function save ()
{ var newname = document .
getElementById ( 'newName' ) .
value ; if ( !yCheckLogicalName
( newname )) { alert ( 'invalid logical name' ) ; return ;
}
module.
set_logicalName ( newname ) ;
module.
saveToFlash () ;
}
-->
</SCRIPT>
</HEAD>
<BODY onload= 'refresh();' >
Module to use: <input id= 'serial' >
<input id= 'msg' style= 'color:red;border:none;' readonly><br>
Current name: <input id= 'curName' readonly><br>
New logical name: <input id= 'newName' >
<a href= 'javascript:save();' >Save</a>
</BODY>
</HTML>
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule() object to find the following modules, and this as long as the returned value is not
function of this
NULL
. Below a short example listing the connected modules.
<HTML>
<HEAD>
<TITLE>Modules inventory</TITLE>
<SCRIPT type= "text/javascript" src= "yocto_api.js" ></SCRIPT>
<SCRIPT language= 'javascript1.5' type= 'text/JavaScript' >
<!--
// Use explicit error handling rather than exceptions
yDisableExceptions () ;
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37
9. Using Yocto-Amp with Javascript
38
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ) != YAPI_SUCCESS ) { alert ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
} function refresh ()
{
yUpdateDeviceList () ; var htmlcode = '' ; var module = yFirstModule () ; while( module ) {
htmlcode += module.
get_serialNumber ()
+ '(' +module.
get_productName () + ")<br>" ;
module = module.
nextModule () ;
} document .
getElementById ( 'list' ) .
innerHTML =htmlcode; setTimeout ( 'refresh()' , 500 ) ;
}
-->
</SCRIPT>
</HEAD>
<BODY onload= 'refresh();' >
<H1>Device list</H1>
<tt><span id= 'list' ></span></tt>
</BODY>
</HTML>
9.4. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected
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9. Using Yocto-Amp with Javascript
bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
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39
40 www.yoctopuce.com
10. Using Yocto-Amp with PHP
PHP is, like Javascript, an atypical language when interfacing with hardware is at stakes.
Nevertheless, using PHP with Yoctopuce modules provides you with the opportunity to very easily create web sites which are able to interact with their physical environment, and this is not available to every web server. This technique has a direct application in home automation: a few Yoctopuce modules, a PHP server, and you can interact with your home from anywhere on the planet, as long as you have an internet connection.
PHP is one of those languages which do not allow you to directly access the hardware layers of your computer. Therefore you need to run a virtual hub on the machine on which your modules are connected.
To start your tests with PHP, you need a PHP 5.3 (or more) server
1
, preferably locally on you machine. If you wish to use the PHP server of your internet provider, it is possible, but you will probably need to configure your ADSL router for it to accept and forward TCP request on the 4444 port.
10.1. Getting ready
Go to the Yoctopuce web site and download the following items:
• The PHP programming library
• The VirtualHub software
3
2
for Windows, Mac OS X, or Linux, depending on your OS
Decompress the library files in a folder of your choice accessible to your web server, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.
10.2. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a PHP code snipplet to use the Current function.
include( 'yocto_api.php' ) ; include( 'yocto_current.php' ) ;
1
A couple of free PHP servers: easyPHP for Windows, MAMP for Mac OS X.
2 www.yoctopuce.com/EN/libraries.php
3 www.yoctopuce.com/EN/virtualhub.php
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41
10. Using Yocto-Amp with PHP
// Get access to your device, through the VirtualHub running locally
yRegisterHub ( 'http://127.0.0.1:4444/' ,$errmsg ) ;
$current = yFindCurrent ( "YAMPMK01-123456.current1" ) ;
// Check that the module is online to handle hot-plug
if( current-> isOnline ())
{
// Use current->get_currentValue(), ...
}
Let's look at these lines in more details.
yocto_api.php and yocto_current.php
These two PHP includes provides access to the functions allowing you to manage Yoctopuce modules. yocto_api.php
must always be included, yocto_current.php
is necessary to manage modules containing a current sensor, such as Yocto-Amp.
yRegisterHub
The yRegisterHub
function allows you to indicate on which machine the Yoctopuce modules are located, more precisely on which machine the VirtualHub software is running. In our case, the
127.0.0.1:4444
address indicates the local machine, port
4444
(the standard port used by
Yoctopuce). You can very well modify this address, and enter the address of another machine on which the VirtualHub software is running.
yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
$current = yFindCurrent ( "YAMPMK01-123456.current1" ) ;
$current = yFindCurrent ( "YAMPMK01-123456.MyFunction" ) ;
$current = yFindCurrent ( "MyModule.current1" ) ;
$current = yFindCurrent ( "MyModule.MyFunction" ) ;
$current = yFindCurrent ( "MyFunction" ) ; yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by corresponding module is present and in working order.
yFindCurrent
allows you to know if the
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Open your preferred text editor
4
, copy the code sample below, save it with the Yoctopuce library files in a location which is accessible to you web server, then use your preferred web browser to access this page. The code is also provided in the directory Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
42
4
If you do not have a text editor, use Notepad rather than Microsoft Word.
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10. Using Yocto-Amp with PHP
<HTML>
<HEAD>
<TITLE>Hello World</TITLE>
</HEAD>
<BODY>
<?php
include( 'yocto_api.php' ) ; include( 'yocto_current.php' ) ;
// Use explicit error handling rather than exceptions
yDisableExceptions () ;
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ,$errmsg ) != YAPI_SUCCESS ) { die ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
}
@$serial = $_GET [ 'serial' ] ; if ( $serial != '' ) {
// Check if a specified module is available online
$sensor= yFindCurrent ( " $serial .current1" ) ; if ( !$sensor-> isOnline ()) { die ( "Module not connected (check serial and USB cable)" ) ;
}
} else {
// or use any connected module suitable for the demo
$sensor = yFirstCurrent () ; if( is_null ( $sensor )) { die ( "No module connected (check USB cable)" ) ;
} else {
$serial = $sensor-> module () -> get_serialnumber () ;
}
}
Print( "Module to use: <input name='serial' value=' $serial '><br>" ) ; if ( $sensor-> isOnline ())
{ $sensorDC = yFindCurrent ( $serial.
".current1" ) ;
$sensorAC = yFindCurrent ( $serial.
".current2" ) ;
$DC = $sensorDC-> get_currentValue () ;
$AC = $sensorAC-> get_currentValue () ;
Print( "Current, DC : $DC mA AC : $AC mA <br>" ) ;
}
// trigger auto-refresh after one second
Print( "<script language='javascript1.5' type='text/JavaScript'> \n" ) ;
Print( "setTimeout('window.location.reload()',1000);" ) ;
Print( "</script> \n" ) ;
?>
</BODY>
</HTML>
10.3. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
<HTML>
<HEAD>
<TITLE>Module Control</TITLE>
</HEAD>
<BODY>
<FORM method='get'>
<?php
include( 'yocto_api.php' ) ;
// Use explicit error handling rather than exceptions
yDisableExceptions () ;
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ,$errmsg ) != YAPI_SUCCESS ) { die ( "Cannot contact VirtualHub on 127.0.0.1 : " .$errmsg ) ;
}
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10. Using Yocto-Amp with PHP
44
@$serial = $_GET [ 'serial' ] ; if ( $serial != '' ) {
// Check if a specified module is available online
$module = yFindModule ( " $serial " ) ; if ( !$module-> isOnline ()) { die ( "Module not connected (check serial and USB cable)" ) ;
}
} else {
// or use any connected module suitable for the demo
$module = yFirstModule () ; if( $module ) {
// skip VirtualHub
$module = $module-> nextModule () ;
} if( is_null ( $module )) { die ( "No module connected (check USB cable)" ) ;
} else {
$serial = $module-> get_serialnumber () ;
}
}
Print( "Module to use: <input name='serial' value=' $serial '><br>" ) ; if ( isset ( $_GET [ 'beacon' ])) { if ( $_GET [ 'beacon' ] == 'ON' )
$module-> set_beacon ( Y_BEACON_ON ) ; else
$module-> set_beacon ( Y_BEACON_OFF ) ;
} printf ( 'serial: %s<br>' ,$module-> get_serialNumber ()) ; printf ( 'logical name: %s<br>' ,$module-> get_logicalName ()) ; printf ( 'luminosity: %s<br>' ,$module-> get_luminosity ()) ; print( 'beacon: ' ) ; if( $module-> get_beacon () == Y_BEACON_ON ) { printf ( "<input type='radio' name='beacon' value='ON' checked>ON " ) ; printf ( "<input type='radio' name='beacon' value='OFF'>OFF<br>" ) ;
} else { printf ( "<input type='radio' name='beacon' value='ON'>ON " ) ; printf ( "<input type='radio' name='beacon' value='OFF' checked>OFF<br>" ) ;
} printf ( 'upTime: %s sec<br>' , intVal ( $module-> get_upTime () / 1000 )) ; printf ( 'USB current: %smA<br>' ,$module-> get_usbCurrent ()) ; printf ( 'logs:<br><pre>%s</pre>' ,$module-> get_lastLogs ()) ;
?>
<input type='submit' value='refresh'>
</FORM>
</BODY>
</HTML>
Each property xxx
of the module can be read thanks to a method of type properties which are not read-only can be modified with the help of the get_xxxx() set_xxx()
, and
method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx()
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash()
method. The short example below allows you to modify the logical name of a module.
<HTML>
<HEAD>
<TITLE>save settings</TITLE>
<BODY>
<FORM method='get'>
<?php
include( 'yocto_api.php' ) ;
// Use explicit error handling rather than exceptions
yDisableExceptions () ;
// Setup the API to use the VirtualHub on local machine
if( yRegisterHub ( 'http://127.0.0.1:4444/' ,$errmsg ) != YAPI_SUCCESS ) {
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10. Using Yocto-Amp with PHP
die ( "Cannot contact VirtualHub on 127.0.0.1" ) ;
}
@$serial = $_GET [ 'serial' ] ; if ( $serial != '' ) {
// Check if a specified module is available online
$module = yFindModule ( " $serial " ) ; if ( !$module-> isOnline ()) { die ( "Module not connected (check serial and USB cable)" ) ;
}
} else {
// or use any connected module suitable for the demo
$module = yFirstModule () ; if( $module ) {
// skip VirtualHub
$module = $module-> nextModule () ;
} if( is_null ( $module )) { die ( "No module connected (check USB cable)" ) ;
} else {
$serial = $module-> get_serialnumber () ;
}
}
Print( "Module to use: <input name='serial' value=' $serial '><br>" ) ; if ( isset ( $_GET [ 'newname' ])){
$newname = $_GET [ 'newname' ] ; if ( !yCheckLogicalName
( $newname )) die ( 'Invalid name' ) ;
$module-> set_logicalName ( $newname ) ;
$module-> saveToFlash () ;
} printf ( "Current name: %s <br>" , $module-> get_logicalName ()) ; print( "New name: <input name='newname' value='' maxlength=19><br>" ) ;
?>
<input type='submit'>
</FORM>
</BODY>
</HTML>
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule() object to find the following modules, and this as long as the returned value is not
function of this
NULL
. Below a short example listing the connected modules.
<HTML>
<HEAD>
<TITLE>inventory</TITLE>
</HEAD>
<BODY>
<H1>Device list</H1>
<TT>
<?php
include( 'yocto_api.php' ) ;
yRegisterHub ( "http://127.0.0.1:4444/" ) ;
$module = yFirstModule () ; while ( !
is_null ( $module )) { printf ( " %s ( %s )<br>" , $module-> get_serialNumber () ,
$module-> get_productName ()) ;
$module=$module-> nextModule () ;
}
?>
</TT>
</BODY>
</HTML>
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45
10. Using Yocto-Amp with PHP
10.4. HTTP callback API and NAT filters
The PHP library is able to work in a specific mode called HTTP callback Yocto-API. With this mode, you can control Yoctopuce devices installed behind a NAT filter, such as a DSL router for example, and this without needing to open a port. The typical application is to control Yoctopuce devices, located on a private network, from a public web site.
The NAT filter: advantages and disadvantages
A DSL router which translates network addresses (NAT) works somewhat like a private phone switchboard (a PBX): internal extensions can call each other and call the outside; but seen from the outside, there is only one official phone number, that of the switchboard itself. You cannot reach the internal extensions from the outside.
Typical DSL configuration: LAN machines are isolated from the outside by the DSL router
Transposed to the network, we have the following: appliances connected to your home automation network can communicate with one another using a local IP address (of the 192.168.xxx.yyy type), and contact Internet servers through their public address. However, seen from the outside, you have only one official IP address, assigned to the DSL router only, and you cannot reach your network appliances directly from the outside. It is rather restrictive, but it is a relatively efficient protection against intrusions.
46
Responses from request from LAN machines are routed.
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10. Using Yocto-Amp with PHP
But requests from the outside are blocked.
Seeing Internet without being seen provides an enormous security advantage. However, this signifies that you cannot, a priori, set up your own web server at home to control a home automation installation from the outside. A solution to this problem, advised by numerous home automation system dealers, consists in providing outside visibility to your home automation server itself, by adding a routing rule in the NAT configuration of the DSL router. The issue of this solution is that it exposes the home automation server to external attacks.
The HTTP callback API solves this issue without having to modify the DSL router configuration. The module control script is located on an external site, and it is the VirtualHub which is in charge of calling it a regular intervals.
The HTTP callback API uses the VirtualHub which initiates the requests.
Configuration
The callback API thus uses the VirtualHub as a gateway. All the communications are initiated by the
VirtualHub. They are thus outgoing communications and therefore perfectly authorized by the DSL router.
You must configure the VirtualHub so that it calls the PHP script on a regular basis. To do so:
1. Launch a VirtualHub
2. Access its interface, usually 127.0.0.1:4444
3. Click on the configure button of the line corresponding to the VirtualHub itself
4. Click on the edit button of the Outgoing callbacks section
Click on the "configure" button on the first line
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47
10. Using Yocto-Amp with PHP
Click on the "edit" button of the "Outgoing callbacks" section
48
And select "Yocto-API callback".
You then only need to define the URL of the PHP script and, if need be, the user name and password to access this URL. Supported authentication methods are basic and digest. The second method is safer than the first one because it does not allow transfer of the password on the network.
Usage
From the programmer standpoint, the only difference is at the level of the yRegisterHub function call.
Instead of using an IP address, you must use the callback string (or http://callback which is equivalent).
include( "yocto_api.php" ) ; yRegisterHub ( "callback" ) ;
The remainder of the code stays strictly identical. On the VirtualHub interface, at the bottom of the configuration window for the HTTP callback API , there is a button allowing you to test the call to the
PHP script.
Be aware that the PHP script controlling the modules remotely through the HTTP callback API can be called only by the VirtualHub. Indeed, it requires the information posted by the VirtualHub to function. To code a web site which controls Yoctopuce modules interactively, you must create a user interface which stores in a file or in a database the actions to be performed on the Yoctopuce modules. These actions are then read and run by the control script.
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10. Using Yocto-Amp with PHP
Common issues
For the HTTP callback API to work, the PHP option allow_url_fopen must be set. Some web site hosts do not set it by default. The problem then manifests itself with the following error: error: URL file-access is disabled in the server configuration
To set this option, you must create, in the repertory where the control PHP script is located, an .htaccess file containing the following line: php_flag "allow_url_fopen" "On"
Depending on the security policies of the host, it is sometimes impossible to authorize this option at the root of the web site, or even to install PHP scripts receiving data from a POST HTTP. In this case, place the PHP script in a subdirectory.
Limitations
This method that allows you to go through NAT filters cheaply has nevertheless a price.
Communications being initiated by the VirtualHub at a more or less regular interval, reaction time to an event is clearly longer than if the Yoctopuce modules were driven directly. You can configure the reaction time in the specific window of the VirtualHub, but it is at least of a few seconds in the best case.
The HTTP callback Yocto-API mode is currently available in PHP and Node.JS only.
10.5. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected
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49
10. Using Yocto-Amp with PHP
bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
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11. Using Yocto-Amp with C++
C++ is not the simplest language to master. However, if you take care to limit yourself to its essential functionalities, this language can very well be used for short programs quickly coded, and it has the advantage of being easily ported from one operating system to another. Under Windows, all the examples and the project models are tested with Microsoft Visual Studio 2010 Express, freely available on the Microsoft web site
1
. Under Mac OS X, all the examples and project models are tested with XCode 4, available on the App Store. Moreover, under Max OS X and under Linux, you can compile the examples using a command line with GCC using the provided
GNUmakefile
. In the same manner under Windows, a
Makefile
allows you to compile examples using a command line, fully knowing the compilation and linking arguments.
Yoctopuce C++ libraries
2
are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from C++. The library is naturally also available as binary files, so that you can link it directly if you prefer.
You will soon notice that the C++ API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You will find in the last section of this chapter all the information needed to create a wholly new project linked with the Yoctopuce libraries.
11.1. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a C++ code snipplet to use the Current function.
#include "yocto_api.h"
#include "yocto_current.h"
[ ...
]
String errmsg;
YCurrent *current;
// Get access to your device, connected locally on USB for instance
yRegisterHub ( "usb" , errmsg ) ; current = yFindCurrent ( "YAMPMK01-123456.current1" ) ;
1 http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-cpp-express
2 www.yoctopuce.com/EN/libraries.php
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51
11. Using Yocto-Amp with C++
52
// Hot-plug is easy: just check that the device is online
if( current-> isOnline ())
{
// Use current->get_currentValue(), ...
}
Let's look at these lines in more details.
yocto_api.h et yocto_current.h
These two include files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h
must always be used, yocto_current.h
is necessary to manage modules containing a current sensor, such as Yocto-Amp.
yRegisterHub
The yRegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter
"usb"
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI_SUCCESS
and errmsg
contains the error message.
yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
YCurrent *current = yFindCurrent ( "YAMPMK01-123456.current1" ) ;
YCurrent *current = yFindCurrent ( "YAMPMK01-123456.MyFunction" ) ;
YCurrent *current = yFindCurrent ( "MyModule.current1" ) ;
YCurrent *current = yFindCurrent ( "MyModule.MyFunction" ) ;
YCurrent *current = yFindCurrent ( "MyFunction" ) ; yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by corresponding module is present and in working order.
yFindCurrent
allows you to know if the
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Launch your C++ environment and open the corresponding sample project provided in the directory
Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library. If you prefer to work with your favorite text editor, open the file main.cpp
, and type make
to build the example when you are done.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
#include "yocto_api.h"
#include "yocto_current.h"
#include <iostream>
#include <stdlib.h> using namespace std;
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11. Using Yocto-Amp with C++
static void usage (void)
{ cout << "usage: demo <serial_number> " << endl ; cout << " demo <logical_name>" << endl ; cout << " demo any (use any discovered device)" << endl ; u64 now = yGetTickCount () ;
// dirty active wait loop
while ( yGetTickCount () -now< 3000 ) ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{ string errmsg; string target;
YCurrent *sensor;
YCurrent *sensorAC;
YCurrent *sensorDC;
YModule *m; if ( argc < 2 ) usage () ;
target = ( string ) argv [ 1 ] ;
YAPI:: DisableExceptions () ;
// Setup the API to use local USB devices
if ( YAPI:: RegisterHub ( "usb" , errmsg ) != YAPI_SUCCESS ) { cerr << "RegisterHub error: " << errmsg << endl ; return 1 ;
} if ( target == "any" ) {
// retreive any voltage sensor (can be AC or DC)
sensor = YCurrent:: FirstCurrent () ; if ( sensor== NULL ) { cerr << "No module connected (Check cable)" << endl ; exit ( 1 ) ;
}
} else {
sensor = YCurrent:: FindCurrent ( target + ".current1" ) ;
}
// we need to retreive both DC and AC voltage from the device.
if ( sensor-> isOnline ()) {
m = sensor-> get_module () ;
sensorDC = YCurrent:: FindCurrent ( m-> get_serialNumber () + ".current1" ) ;
sensorAC = YCurrent:: FindCurrent ( m-> get_serialNumber () + ".current2" ) ;
} else { cerr << "No module connected (Check cable)" << endl ; exit ( 1 ) ;
} while( 1 ) { if ( !sensorDC-> isOnline ()) { cout << "Module disconnected" << endl ; break ;
} cout << "Current, DC : " << sensorDC-> get_currentValue () << " mA" ; cout << " AC : " << sensorAC-> get_currentValue () << " mA" ; cout << " (press Ctrl-C to exit)" << endl ;
YAPI:: Sleep ( 1000 ,errmsg ) ;
} ; return 0 ;
}
11.2. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
#include <iostream>
#include <stdlib.h>
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11. Using Yocto-Amp with C++
54
#include "yocto_api.h" using namespace std; static void usage (const char *exe )
{ cout << "usage: " << exe << " <serial or logical name> [ON/OFF]" << endl ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{ string errmsg;
// Setup the API to use local USB devices
if( yRegisterHub ( "usb" , errmsg ) != YAPI_SUCCESS ) { cerr << "RegisterHub error: " << errmsg << endl ; return 1 ;
} if( argc < 2 )
usage ( argv [ 0 ]) ;
YModule *module = yFindModule ( argv [ 1 ]) ;
// use serial or logical name
if ( module-> isOnline ()) { if ( argc > 2 ) { if ( string ( argv [ 2 ]) == "ON" )
module-> set_beacon ( Y_BEACON_ON ) ; else
module-> set_beacon ( Y_BEACON_OFF ) ;
} cout << "serial: " << module-> get_serialNumber () << endl ; cout << "logical name: " << module-> get_logicalName () << endl ; cout << "luminosity: " << module-> get_luminosity () << endl ; cout << "beacon: " ; if ( module-> get_beacon () ==Y_BEACON_ON ) cout << "ON" << endl ; else cout << "OFF" << endl ; cout << "upTime: " << module-> get_upTime () / 1000 << " sec" << endl ; cout << "USB current: " << module-> get_usbCurrent () << " mA" << endl ; cout << "Logs:" << endl << module-> get_lastLogs () << endl ;
} else { cout << argv [ 1 ] << " not connected (check identification and USB cable)"
<< endl ;
} return 0 ;
}
Each property xxx
of the module can be read thanks to a method of type get_xxxx()
, and properties which are not read-only can be modified with the help of the more details regarding the used functions, refer to the API chapters.
set_xxx()
method. For
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx()
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash()
method. The short example below allows you to modify the logical name of a module.
#include <iostream>
#include <stdlib.h>
#include "yocto_api.h" using namespace std; static void usage (const char *exe )
{
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11. Using Yocto-Amp with C++
cerr << "usage: " << exe << " <serial> <newLogicalName>" << endl ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{ string errmsg;
// Setup the API to use local USB devices
if( yRegisterHub ( "usb" , errmsg ) != YAPI_SUCCESS ) { cerr << "RegisterHub error: " << errmsg << endl ; return 1 ;
} if( argc < 2 )
usage ( argv [ 0 ]) ;
YModule *module = yFindModule ( argv [ 1 ]) ;
// use serial or logical name
if ( module-> isOnline ()) { if ( argc >= 3 ){ string newname = argv [ 2 ] ; if ( !yCheckLogicalName
( newname )){ cerr << "Invalid name (" << newname << ")" << endl ;
usage ( argv [ 0 ]) ;
}
module-> set_logicalName ( newname ) ;
module-> saveToFlash () ;
} cout << "Current name: " << module-> get_logicalName () << endl ;
} else { cout << argv [ 1 ] << " not connected (check identification and USB cable)"
<< endl ;
} return 0 ;
}
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule()
function of this object to find the following modules, and this as long as the returned value is not short example listing the connected modules.
NULL
. Below a
#include <iostream>
#include "yocto_api.h" using namespace std; int main ( int argc, const char * argv [])
{ string errmsg;
// Setup the API to use local USB devices
if( yRegisterHub ( "usb" , errmsg ) != YAPI_SUCCESS ) { cerr << "RegisterHub error: " << errmsg << endl ; return 1 ;
} cout << "Device list: " << endl ;
YModule *module = yFirstModule () ; while ( module != NULL ) { cout << module-> get_serialNumber () << " " ; cout << module-> get_productName () << endl ;
module = module-> nextModule () ;
}
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11. Using Yocto-Amp with C++
return 0 ;
}
11.3. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
11.4. Integration variants for the C++ Yoctopuce library
Depending on your needs and on your preferences, you can integrate the library into your projects in several distinct manners. This section explains how to implement the different options.
Integration in source format
Integrating all the sources of the library into your projects has several advantages:
• It guaranties the respect of the compilation conventions of your project (32/64 bits, inclusion of debugging symbols, unicode or ASCII characters, etc.);
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11. Using Yocto-Amp with C++
• It facilitates debugging if you are looking for the cause of a problem linked to the Yoctopuce library;
• It reduces the dependencies on third party components, for example in the case where you would need to recompile this project for another architecture in many years;
• It does not require the installation of a dynamic library specific to Yoctopuce on the final system, everything is in the executable.
To integrate the source code, the easiest way is to simply include the
Sources
directory of your
Yoctopuce library into your IncludePath, and to add all the files of this directory (including the subdirectory yapi
) to your project.
For your project to build correctly, you need to link with your project the prerequisite system libraries, that is:
• For Windows: the libraries are added automatically
• For Mac OS X: IOKit.framework and CoreFoundation.framework
• For Linux: libm, libpthread, libusb1.0, and libstdc++
Integration as a static library
Integration of the Yoctopuce library as a static library is a simpler manner to build a small executable which uses Yoctopuce modules. You can quickly compile the program with a single command. You do not need to install a dynamic library specific to Yoctopuce, everything is in the executable.
To integrate the static Yoctopuce library to your project, you must include the
Sources
directory of the Yoctopuce library into your IncludePath, and add the sub-directory
Binaries/...
corresponding to your operating system into your libPath.
Then, for you project to build correctly, you need to link with your project the Yoctopuce library and the prerequisite system libraries:
• For Windows: yocto-static.lib
• For Mac OS X: libyocto-static.a, IOKit.framework, and CoreFoundation.framework
• For Linux: libyocto-static.a, libm, libpthread, libusb1.0, and libstdc++.
Note, under Linux, if you wish to compile in command line with GCC, it is generally advisable to link system libraries as dynamic libraries, rather than as static ones. To mix static and dynamic libraries on the same command line, you must pass the following arguments: gcc (...) -Wl,-Bstatic -lyocto-static -Wl,-Bdynamic -lm -lpthread -lusb-1.0 -lstdc++
Integration as a dynamic library
Integration of the Yoctopuce library as a dynamic library allows you to produce an executable smaller than with the two previous methods, and to possibly update this library, if a patch reveals itself necessary, without needing to recompile the source code of the application. On the other hand, it is an integration mode which systematically requires you to copy the dynamic library on the target machine where the application will run (yocto.dll for Windows, libyocto.so.1.0.1 for Mac OS X and
Linux).
To integrate the dynamic Yoctopuce library to your project, you must include the
Sources
directory of the Yoctopuce library into your IncludePath, and add the sub-directory
Binaries/...
corresponding to your operating system into your LibPath.
Then, for you project to build correctly, you need to link with your project the dynamic Yoctopuce library and the prerequisite system libraries:
• For Windows: yocto.lib
• For Mac OS X: libyocto, IOKit.framework, and CoreFoundation.framework
• For Linux: libyocto, libm, libpthread, libusb1.0, and libstdc++.
With GCC, the command line to compile is simply:
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11. Using Yocto-Amp with C++
gcc (...) -lyocto -lm -lpthread -lusb-1.0 -lstdc++
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12. Using Yocto-Amp with Objective-C
Objective-C is language of choice for programming on Mac OS X, due to its integration with the
Cocoa framework. In order to use the Objective-C library, you need XCode version 4.2 (earlier versions will not work), available freely when you run Lion. If you are still under Snow Leopard, you need to be registered as Apple developer to be able to download XCode 4.2. The Yoctopuce library is ARC compatible. You can therefore implement your projects either using the traditional retain /
release method, or using the Automatic Reference Counting.
Yoctopuce Objective-C libraries
1
are integrally provided as source files. A section of the low-level library is written in pure C, but you should not need to interact directly with it: everything was done to ensure the simplest possible interaction from Objective-C.
You will soon notice that the Objective-C API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface. You can find on Yoctopuce blog a detailed example
2
with video shots showing how to integrate the library into your projects.
12.1. Control of the Current function
Launch Xcode 4.2 and open the corresponding sample project provided in the directory Examples/
Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
#import <Foundation/Foundation.h>
#import "yocto_api.h"
#import "yocto_current.h" static void usage (void)
{
NSLog ( @"usage: demo <serial_number> " ) ;
NSLog ( @" demo <logical_name>" ) ;
NSLog ( @" demo any (use any discovered device)" ) ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{
1 www.yoctopuce.com/EN/libraries.php
2 www.yoctopuce.com/EN/article/new-objective-c-library-for-mac-os-x
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12. Using Yocto-Amp with Objective-C
NSError *error;
YCurrent *sensor;
YCurrent *sensorAC;
YCurrent *sensorDC;
YModule *m; if ( argc < 2 ) {
usage () ;
}
@autoreleasepool {
NSString *target = [ NSString stringWithUTF8String:argv [ 1 ]] ;
// Setup the API to use local USB devices
if([ YAPI RegisterHub: @"usb" : &error ] != YAPI_SUCCESS ) {
NSLog ( @"RegisterHub error: %@" , [ error localizedDescription ]) ; return 1 ;
} if ([ target isEqualToString: @"any" ]) {
// retreive any current sensor (can be AC or DC)
sensor = [ YCurrent FirstCurrent ] ; if ( sensor== NULL ) {
NSLog ( @"No module connected (check USB cable)" ) ; return 1 ;
}
} else {
sensor = [ YCurrent FindCurrent: [ target stringByAppendingString: @".current1" ]] ;
}
// we need to retreive both DC and AC current from the device.
if ([ sensor isOnline ]) {
m = [ sensor module ] ;
sensorDC = [ YCurrent FindCurrent: [ m.serialNumber stringByAppendingString: @".current1" ]] ;
sensorAC = [ YCurrent FindCurrent: [ m.serialNumber stringByAppendingString: @".current2" ]] ;
} else {
NSLog ( @"No module connected (check USB cable)" ) ; return 1 ;
} while( 1 ) { if ( !
[ m isOnline ]) {
NSLog ( @"No module connected (check identification and USB cable)" ) ; return 1 ;
}
NSLog ( @"Current DC : %f mA" , [ sensorDC currentValue ]) ;
NSLog ( @" AC : %f mA" , [ sensorAC currentValue ]) ;
NSLog ( @" (press Ctrl-C to exit)" ) ;
[ YAPI Sleep: 1000 : NULL ] ;
}
} return 0 ;
}
There are only a few really important lines in this example. We will look at them in details.
yocto_api.h et yocto_current.h
These two import files provide access to the functions allowing you to manage Yoctopuce modules. yocto_api.h
must always be used, yocto_current.h
is necessary to manage modules containing a current sensor, such as Yocto-Amp.
yRegisterHub
The yRegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter
@"usb"
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI_SUCCESS
and errmsg
contains the error message.
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yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
YCurrent *current = yFindCurrent ( @"YAMPMK01-123456.current1" ) ;
YCurrent *current = yFindCurrent ( @"YAMPMK01-123456.MyFunction" ) ;
YCurrent *current = yFindCurrent ( @"MyModule.current1" ) ;
YCurrent *current = yFindCurrent ( @"MyModule.MyFunction" ) ;
YCurrent *current = yFindCurrent ( @"MyFunction" ) ; yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by yFindCurrent
allows you to know if the corresponding module is present and in working order.
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
12.2. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
#import <Foundation/Foundation.h>
#import "yocto_api.h" static void usage ( const char *exe )
{
NSLog ( @"usage: %s <serial or logical name> [ON/OFF] \n" ,exe ) ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{
NSError *error;
@autoreleasepool {
// Setup the API to use local USB devices
if([ YAPI RegisterHub: @"usb" : &error ] != YAPI_SUCCESS ) {
NSLog ( @"RegisterHub error: %@" , [ error localizedDescription ]) ; return 1 ;
} if( argc < 2 )
usage ( argv [ 0 ]) ;
NSString *serial_or_name = [ NSString stringWithUTF8String:argv [ 1 ]] ;
YModule *module = [ YModule FindModule:serial_or_name ] ;
// use serial or logical name
if ([ module isOnline ]) { if ( argc > 2 ) { if ( strcmp ( argv [ 2 ] , "ON" ) == 0 )
[ module setBeacon:Y_BEACON_ON ] ; else
[ module setBeacon:Y_BEACON_OFF ] ;
}
NSLog ( @"serial: %@ \n" , [ module serialNumber ]) ;
NSLog ( @"logical name: %@
\n"
, [ module logicalName ]) ;
NSLog ( @"luminosity: %d \n" , [ module luminosity ]) ;
NSLog ( @"beacon: " ) ; if ([ module beacon ] == Y_BEACON_ON )
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62
NSLog ( @"ON \n" ) ; else
NSLog ( @"OFF \n" ) ;
NSLog ( @"upTime: %d sec \n" , [ module upTime ] / 1000 ) ;
NSLog ( @"USB current: %d mA
\n"
, [ module usbCurrent ]) ;
NSLog ( @"logs: %@ \n" , [ module get_lastLogs ]) ;
} else {
NSLog ( @"%@ not connected (check identification and USB cable)
\n"
,serial_or_name
) ;
}
} return 0 ;
}
Each property xxx
of the module can be read thanks to a method of type properties which are not read-only can be modified with the help of the get_xxxx set_xxx:
, and
method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx:
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash allows you to modify the logical name of a module.
method. The short example below
#import <Foundation/Foundation.h>
#import "yocto_api.h" static void usage ( const char *exe )
{
NSLog ( @"usage: %s <serial> <newLogicalName> \n" ,exe ) ; exit ( 1 ) ;
} int main ( int argc, const char * argv [])
{
NSError *error;
@autoreleasepool {
// Setup the API to use local USB devices
if( yRegisterHub ( @"usb" , &error ) != YAPI_SUCCESS ) {
NSLog ( @"RegisterHub error: %@" , [ error localizedDescription ]) ; return 1 ;
} if( argc < 2 )
usage ( argv [ 0 ]) ;
NSString *serial_or_name = [ NSString stringWithUTF8String:argv [ 1 ]] ;
YModule *module = yFindModule ( serial_or_name ) ;
// use serial or logical name
if ( module.isOnline
) { if ( argc >= 3 ){
NSString *newname = [ NSString stringWithUTF8String:argv [ 2 ]] ; if ( !yCheckLogicalName
( newname )){
NSLog ( @"Invalid name (%@) \n" , newname ) ;
usage ( argv [ 0 ]) ;
}
module.logicalName = newname;
[ module saveToFlash ] ;
}
NSLog ( @"Current name: %@ \n" , module.logicalName
) ;
} else {
NSLog ( @"%@ not connected (check identification and USB cable) \n" ,serial_or_name
) ;
}
} return 0 ;
}
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Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule()
function of this object to find the following modules, and this as long as the returned value is not short example listing the connected modules.
NULL
. Below a
#import <Foundation/Foundation.h>
#import "yocto_api.h" int main ( int argc, const char * argv [])
{
NSError *error;
@autoreleasepool {
// Setup the API to use local USB devices
if( yRegisterHub ( @"usb" , &error ) != YAPI_SUCCESS ) {
NSLog ( @"RegisterHub error: %@ \n" , [ error localizedDescription ]) ; return 1 ;
}
NSLog ( @"Device list: \n" ) ;
YModule *module = yFirstModule () ; while ( module != nil ) {
NSLog ( @"%@ %@" ,module.serialNumber, module.productName
) ;
module = [ module nextModule ] ;
}
} return 0 ;
}
12.3. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every
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12. Using Yocto-Amp with Objective-C
line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
64 www.yoctopuce.com
13. Using Yocto-Amp with Visual Basic .NET
VisualBasic has long been the most favored entrance path to the Microsoft world. Therefore, we had to provide our library for this language, even if the new trend is shifting to C#. All the examples and the project models are tested with Microsoft VisualBasic 2010 Express, freely available on the
Microsoft web site
1
.
13.1. Installation
Download the Visual Basic Yoctopuce library from the Yoctopuce web site
2
. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the
Sources
directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual Basic 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.
13.2. Using the Yoctopuce API in a Visual Basic project
The Visual Basic.NET Yoctopuce library is composed of a DLL and of source files in Visual Basic.
The DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules
3
. The source files in Visual Basic manage the high level part of the
API. Therefore, your need both this DLL and the .vb files of the project managing Yoctopuce modules.
sources
directory to create a
Configuring a Visual Basic project
The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".
A file selection window opens. Select the yocto_api.vb
file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.
You then have the choice between simply adding these files to your project, or to add them as links
(the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.
1 http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-basic-express
2 www.yoctopuce.com/EN/libraries.php
3
The sources of this DLL are available in the C++ API
www.yoctopuce.com
65
13. Using Yocto-Amp with Visual Basic .NET
Then add in the same manner the yapi.dll
DLL, located in the
Sources/dll
directory
4
. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.
13.3. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a Visual Basic code snipplet to use the Current function.
[ ...
]
Dim errmsg As String errmsg
Dim current As YCurrent
REM Get access to your device, connected locally on USB for instance
yRegisterHub ( "usb" , errmsg ) current = yFindCurrent ( "YAMPMK01-123456.current1" )
REM Hot-plug is easy: just check that the device is online
If ( current.
isOnline ()) Then
REM Use current.get_currentValue(), ...
End If
Let's look at these lines in more details.
yRegisterHub
The yRegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter
"usb"
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI_SUCCESS
and errmsg
contains the error message.
yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current = yFindCurrent ( "YAMPMK01-123456.current1" ) current = yFindCurrent ( "YAMPMK01-123456.MyFunction" ) current = yFindCurrent ( "MyModule.current1" ) current = yFindCurrent ( "MyModule.MyFunction" ) current = yFindCurrent ( "MyFunction" ) yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by corresponding module is present and in working order.
yFindCurrent
allows you to know if the
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
66
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Remember to change the filter of the selection window, otherwise the DLL will not show.
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13. Using Yocto-Amp with Visual Basic .NET
A real example
Launch Microsoft VisualBasic and open the corresponding sample project provided in the directory
Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
Module Module1
Private Sub Usage ()
Dim execname As String = System .
AppDomain .
CurrentDomain .
FriendlyName
Console .
WriteLine ( "Usage:" )
Console .
WriteLine ( execname + " demo <serial_number>" )
Console .
WriteLine ( execname + " demo <logical_name>" )
Console .
WriteLine ( execname + " demo any " )
System.
Threading .
Thread .
Sleep ( 2500 )
End
End Sub
Sub Die (ByVal msg As String )
Console .
WriteLine ( msg + "(check USB cable)" )
End
End Sub
Sub Main ()
Dim argv () As String = System .
Environment .
GetCommandLineArgs ()
Dim errmsg As String = ""
Dim target As String
Dim sensor As YCurrent
Dim sensorDC As YCurrent = Nothing
Dim sensorAC As YCurrent = Nothing
Dim m As YModule = Nothing
If argv.
Length < 2 Then Usage ()
target = argv ( 1 )
REM Setup the API to use local USB devices
If ( yRegisterHub ( "usb" , errmsg ) <> YAPI_SUCCESS ) Then
Console .
WriteLine ( "RegisterHub error: " + errmsg )
End
End If
If target = "any" Then
REM retreive any voltage sensor (can be AC or DC)
sensor = yFirstCurrent ()
If sensor Is Nothing Then Die ( "No module connected" )
Else
sensor = yFindCurrent ( target + ".voltage1" )
End If
REM we need to retreive both DC and AC voltage from the device.
If ( sensor.
isOnline ()) Then
m = sensor.
get_module ()
sensorDC = yFindCurrent ( m.
get_serialNumber () + ".current1" )
sensorAC = yFindCurrent ( m.
get_serialNumber () + ".current2" )
Else
Die ( "Module not connected" )
End If
While ( True )
If Not ( m.
isOnline ()) Then Die ( "Module not connected" )
Console .
Write( "DC: " + sensorDC.
get_currentValue () .
ToString () + " mA " )
Console .
Write( "AC: " + sensorAC.
get_currentValue () .
ToString () + " mA " )
Console .
WriteLine ( " (press Ctrl-C to exit)" )
ySleep ( 1000 , errmsg )
End While
End Sub
End Module
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13. Using Yocto-Amp with Visual Basic .NET
68
13.4. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
Imports System.
IO
Imports System .
Environment
Module Module1
Sub usage ()
Console .
WriteLine ( "usage: demo <serial or logical name> [ON/OFF]" )
End
End Sub
Sub Main ()
Dim argv () As String = System .
Environment .
GetCommandLineArgs ()
Dim errmsg As String = ""
Dim m As ymodule
If ( yRegisterHub ( "usb" , errmsg ) <> YAPI_SUCCESS ) Then
Console .
WriteLine ( "RegisterHub error:" + errmsg )
End
End If
If argv.
Length < 2 Then usage ()
m = yFindModule ( argv ( 1 ))
REM use serial or logical name
If ( m.
isOnline ()) Then
If argv.
Length > 2 Then
If argv ( 2 ) = "ON" Then m.
set_beacon ( Y_BEACON_ON )
If argv ( 2 ) = "OFF" Then m.
set_beacon ( Y_BEACON_OFF )
End If
Console .
WriteLine ( "serial: " + m.
get_serialNumber ())
Console .
WriteLine ( "logical name: " + m.
get_logicalName ())
Console .
WriteLine ( "luminosity: " + Str ( m.
get_luminosity ()))
Console .
Write( "beacon: " )
If ( m.
get_beacon () = Y_BEACON_ON ) Then
Console .
WriteLine ( "ON" )
Else
Console .
WriteLine ( "OFF" )
End If
Console .
WriteLine ( "upTime: " + Str ( m.
get_upTime () / 1000 ) + " sec" )
Console .
WriteLine ( "USB current: " + Str ( m.
get_usbCurrent ()) + " mA" )
Console .
WriteLine ( "Logs:" )
Console .
WriteLine ( m.
get_lastLogs ())
Else
Console .
WriteLine ( argv ( 1 ) + " not connected (check identification and USB cable)" )
End If
End Sub
End Module
Each property xxx
of the module can be read thanks to a method of type properties which are not read-only can be modified with the help of the get_xxxx() set_xxx()
, and
method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx()
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash()
method. The short example below allows you to modify the logical name of a module.
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13. Using Yocto-Amp with Visual Basic .NET
Module Module1
Sub usage ()
Console .
WriteLine ( "usage: demo <serial or logical name> <new logical name>" )
End
End Sub
Sub Main ()
Dim argv () As String = System .
Environment .
GetCommandLineArgs ()
Dim errmsg As String = ""
Dim newname As String
Dim m As YModule
If ( argv.
Length <> 3 ) Then usage ()
REM Setup the API to use local USB devices
If yRegisterHub ( "usb" , errmsg ) <> YAPI_SUCCESS Then
Console .
WriteLine ( "RegisterHub error: " + errmsg )
End
End If
m = yFindModule ( argv ( 1 ))
REM use serial or logical name
If m.
isOnline () Then
newname = argv ( 2 )
If (Not yCheckLogicalName ( newname )) Then
Console .
WriteLine ( "Invalid name (" + newname + ")" )
End
End If
m.
set_logicalName ( newname )
m.
saveToFlash ()
REM do not forget this
Console .
Write( "Module: serial= " + m.
get_serialNumber )
Console .
Write( " / name= " + m.
get_logicalName ())
Else
Console .
Write( "not connected (check identification and USB cable" )
End If
End Sub
End Module
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule()
function of this object to find the following modules, and this as long as the returned value is not
Nothing
. Below a short example listing the connected modules.
Module Module1
Sub Main ()
Dim M As ymodule
Dim errmsg As String = ""
REM Setup the API to use local USB devices
If yRegisterHub ( "usb" , errmsg ) <> YAPI_SUCCESS Then
Console .
WriteLine ( "RegisterHub error: " + errmsg )
End
End If
Console .
WriteLine ( "Device list" )
M = yFirstModule ()
While M IsNot Nothing
Console .
WriteLine ( M.
get_serialNumber () + " (" + M.
get_productName () + ")" )
M = M.
nextModule ()
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13. Using Yocto-Amp with Visual Basic .NET
End While
End Sub
End Module
13.5. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
70 www.yoctopuce.com
14. Using Yocto-Amp with C#
C# (pronounced C-Sharp) is an object-oriented programming language promoted by Microsoft, it is somewhat similar to Java. Like Visual-Basic and Delphi, it allows you to create Windows applications quite easily. All the examples and the project models are tested with Microsoft C# 2010 Express, freely available on the Microsoft web site
1
.
14.1. Installation
Download the Visual C# Yoctopuce library from the Yoctopuce web site
2
. There is no setup program, simply copy the content of the zip file into the directory of your choice. You mostly need the content of the
Sources
directory. The other directories contain the documentation and a few sample programs. All sample projects are Visual C# 2010, projects, if you are using a previous version, you may have to recreate the projects structure from scratch.
14.2. Using the Yoctopuce API in a Visual C# project
The Visual C#.NET Yoctopuce library is composed of a DLL and of source files in Visual C#. The
DLL is not a .NET DLL, but a classic DLL, written in C, which manages the low level communications with the modules
3
. The source files in Visual C# manage the high level part of the API. Therefore, your need both this DLL and the .cs files of the
Yoctopuce modules.
sources
directory to create a project managing
Configuring a Visual C# project
The following indications are provided for Visual Studio Express 2010, but the process is similar for other versions. Start by creating your project. Then, on the Solution Explorer panel, right click on your project, and select "Add" and then "Add an existing item".
A file selection window opens. Select the yocto_api.cs
file and the files corresponding to the functions of the Yoctopuce modules that your project is going to manage. If in doubt, select all the files.
You then have the choice between simply adding these files to your project, or to add them as links
(the Add button is in fact a scroll-down menu). In the first case, Visual Studio copies the selected files into your project. In the second case, Visual Studio simply keeps a link on the original files. We recommend you to use links, which makes updates of the library much easier.
1 http://www.microsoft.com/visualstudio/en-us/products/2010-editions/visual-csharp-express
2 www.yoctopuce.com/EN/libraries.php
3
The sources of this DLL are available in the C++ API
www.yoctopuce.com
71
14. Using Yocto-Amp with C#
Then add in the same manner the yapi.dll
DLL, located in the
Sources/dll
directory
4
. Then, from the Solution Explorer window, right click on the DLL, select Properties and in the Properties panel, set the Copy to output folder to always. You are now ready to use your Yoctopuce modules from Visual Studio.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.
14.3. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a C# code snipplet to use the Current function.
[ ...
] string errmsg = "" ;
YCurrent current;
// Get access to your device, connected locally on USB for instance
YAPI.
RegisterHub ( "usb" , errmsg ) ; current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) ;
// Hot-plug is easy: just check that the device is online
if ( current.
isOnline ())
{
// Use current.get_currentValue(); ...
}
Let's look at these lines in more details.
YAPI.RegisterHub
The
YAPI.RegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter
"usb"
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI.SUCCESS
and errmsg
contains the error message.
YCurrent.FindCurrent
The
YCurrent.FindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) ; current = YCurrent.
FindCurrent ( "YAMPMK01-123456.MyFunction" ) ; current = YCurrent.
FindCurrent ( "MyModule.current1" ) ; current = YCurrent.
FindCurrent ( "MyModule.MyFunction" ) ; current = YCurrent.
FindCurrent ( "MyFunction" ) ;
YCurrent.FindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by
YCurrent.FindCurrent
allows you to know if the corresponding module is present and in working order.
72
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14. Using Yocto-Amp with C#
get_currentValue
The get_currentValue()
method of the object returned by
YCurrent.FindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Launch Microsoft Visual C# and open the corresponding sample project provided in the directory
Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
using System ; using System.Collections.Generic
; using System.Linq
; using System.Text
; namespace ConsoleApplication1
{ class Program
{ static void usage ()
{ string execname = System .
AppDomain .
CurrentDomain .
FriendlyName ;
Console .
WriteLine ( "Usage" ) ;
Console .
WriteLine ( execname + " <serial_number>" ) ;
Console .
WriteLine ( execname + " <logical_name>" ) ;
Console .
WriteLine ( execname + " any " ) ;
System.
Threading .
Thread .
Sleep ( 2500 ) ;
Environment .
Exit ( 0 ) ;
} static void die ( string msg )
{
Console .
WriteLine ( msg + " (check USB cable) " ) ;
Environment .
Exit ( 0 ) ;
} static void Main ( string [] args )
{ string errmsg = "" ; string target;
YCurrent sensor;
YCurrent sensorDC = null ;
YCurrent sensorAC = null ;
YModule m = null ; if ( args.
Length < 1 ) usage () ;
target = args [ 0 ] .
ToUpper () ;
// Setup the API to use local USB devices
if ( YAPI.
RegisterHub ( "usb" , ref errmsg ) != YAPI.
SUCCESS )
{
Console .
WriteLine ( "RegisterHub error: " + errmsg ) ;
Environment .
Exit ( 0 ) ;
} if ( target == "ANY" )
{
// retreive any voltage sensor (can be AC or DC)
sensor = YCurrent.
FirstCurrent () ; if ( sensor == null ) die ( "No module connected" ) ;
} else sensor = YCurrent.
FindCurrent ( target + ".current1" ) ;
// we need to retreive both DC and AC voltage from the device.
if ( sensor.
isOnline ())
{
m = sensor.
get_module () ;
sensorDC = YCurrent.
FindCurrent ( m.
get_serialNumber () + ".current1" ) ;
sensorAC = YCurrent.
FindCurrent ( m.
get_serialNumber () + ".current2" ) ;
}
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14. Using Yocto-Amp with C#
74
else die ( "Module not connected" ) ; while ( true )
{ if ( !m.
isOnline ()) die ( "Module not connected" ) ;
Console .
Write ( "DC: " + sensorDC.
get_currentValue () .
ToString () + " mA " ) ;
Console .
Write ( "AC: " + sensorAC.
get_currentValue () .
ToString () + " mA " ) ;
Console .
WriteLine ( " (press Ctrl-C to exit)" ) ;
YAPI.
Sleep ( 1000 , ref errmsg ) ;
}
}
}
}
14.4. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
using System ; using System.Collections.Generic
; using System.Linq
; using System.Text
; namespace ConsoleApplication1
{ class Program
{ static void usage ()
{ string execname = System .
AppDomain .
CurrentDomain .
FriendlyName ;
Console .
WriteLine ( "Usage:" ) ;
Console .
WriteLine ( execname+ " <serial or logical name> [ON/OFF]" ) ;
System.
Threading .
Thread .
Sleep ( 2500 ) ;
Environment .
Exit ( 0 ) ;
} static void Main ( string [] args )
{
YModule m; string errmsg = "" ; if ( YAPI.
RegisterHub ( "usb" , ref errmsg ) != YAPI.
SUCCESS )
{
Console .
WriteLine ( "RegisterHub error: " + errmsg ) ;
Environment .
Exit ( 0 ) ;
} if ( args.
Length < 1 ) usage () ;
m = YModule.
FindModule ( args [ 0 ]) ;
// use serial or logical name
if ( m.
isOnline ())
{ if ( args.
Length >= 2 )
{ if ( args [ 1 ] .
ToUpper () == "ON" ) { m.
set_beacon ( YModule.
BEACON_ON ) ; } if ( args [ 1 ] .
ToUpper () == "OFF" ) { m.
set_beacon ( YModule.
BEACON_OFF ) ; }
}
Console .
WriteLine ( "serial: " + m.
get_serialNumber ()) ;
Console .
WriteLine ( "logical name: " + m.
get_logicalName ()) ;
Console .
WriteLine ( "luminosity: " + m.
get_luminosity () .
ToString ()) ;
Console .
Write ( "beacon: " ) ; if ( m.
get_beacon () == YModule.
BEACON_ON )
Console .
WriteLine ( "ON" ) ; else
Console .
WriteLine ( "OFF" ) ;
Console .
WriteLine ( "upTime: " + ( m.
get_upTime () / 1000 ) .
ToString () + " sec" ) ;
Console .
WriteLine ( "USB current: " + m.
get_usbCurrent () .
ToString () + " mA" ) ;
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14. Using Yocto-Amp with C#
Console .
WriteLine ( "Logs: \r\n" + m.
get_lastLogs ()) ;
} else
Console .
WriteLine ( args [ 0 ] + " not connected (check identification and USB cable)" ) ;
}
}
}
Each property xxx
of the module can be read thanks to a method of type
YModule.get_xxxx()
, and properties which are not read-only can be modified with the help of the
YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding
YModule.set_xxx()
function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the
YModule.saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the
YModule.revertFromFlash()
The short example below allows you to modify the logical name of a module.
method. using System ; using System.Collections.Generic
; using System.Linq
; using System.Text
; namespace ConsoleApplication1
{ class Program
{ static void usage ()
{ string execname = System .
AppDomain .
CurrentDomain .
FriendlyName ;
Console .
WriteLine ( "Usage:" ) ;
Console .
WriteLine ( "usage: demo <serial or logical name> <new logical name>" ) ;
System.
Threading .
Thread .
Sleep ( 2500 ) ;
Environment .
Exit ( 0 ) ;
} static void Main ( string [] args )
{
YModule m; string errmsg = "" ; string newname; if ( args.
Length != 2 ) usage () ; if ( YAPI.
RegisterHub ( "usb" , ref errmsg ) != YAPI.
SUCCESS )
{
Console .
WriteLine ( "RegisterHub error: " + errmsg ) ;
Environment .
Exit ( 0 ) ;
}
m = YModule.
FindModule ( args [ 0 ]) ;
// use serial or logical name
if ( m.
isOnline ())
{
newname = args [ 1 ] ; if ( !YAPI.
CheckLogicalName ( newname ))
{
Console .
WriteLine ( "Invalid name (" + newname + ")" ) ;
Environment .
Exit ( 0 ) ;
}
m.
set_logicalName ( newname ) ;
m.
saveToFlash () ;
// do not forget this
Console .
Write ( "Module: serial= " + m.
get_serialNumber ()) ;
Console .
WriteLine ( " / name= " + m.
get_logicalName ()) ;
} else
Console .
Write ( "not connected (check identification and USB cable" ) ;
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14. Using Yocto-Amp with C#
}
}
}
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the
YModule.saveToFlash()
function only 100000 times in the life of the module.
Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the
YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null
. Below a short example listing the connected modules.
using System ; using System.Collections.Generic
; using System.Linq
; using System.Text
; namespace ConsoleApplication1
{ class Program
{ static void Main ( string [] args )
{
YModule m; string errmsg = "" ; if ( YAPI.
RegisterHub ( "usb" , ref errmsg ) != YAPI.
SUCCESS )
{
Console .
WriteLine ( "RegisterHub error: " + errmsg ) ;
Environment .
Exit ( 0 ) ;
}
Console .
WriteLine ( "Device list" ) ;
m = YModule.
FirstModule () ; while ( m!= null )
{ Console .
WriteLine ( m.
get_serialNumber () + " (" + m.
get_productName () + ")" ) ;
m = m.
nextModule () ;
}
}
}
}
14.5. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
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14. Using Yocto-Amp with C#
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
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15. Using Yocto-Amp with Delphi
Delphi is a descendent of Turbo-Pascal. Originally, Delphi was produced by Borland, Embarcadero now edits it. The strength of this language resides in its ease of use, as anyone with some notions of the Pascal language can develop a Windows application in next to no time. Its only disadvantage is to cost something
1
.
Delphi libraries are provided not as VCL components, but directly as source files. These files are compatible with most Delphi versions.
2
To keep them simple, all the examples provided in this documentation are console applications.
Obviously, the libraries work in a strictly identical way with VCL applications.
You will soon notice that the Delphi API defines many functions which return objects. You do not need to deallocate these objects yourself, the API does it automatically at the end of the application.
15.1. Preparation
Go to the Yoctopuce web site and download the Yoctopuce Delphi libraries
3
. Uncompress everything in a directory of your choice, add the subdirectory sources in the list of directories of Delphi libraries.
4
By default, the Yoctopuce Delphi library uses the yapi.dll DLL, all the applications you will create with
Delphi must have access to this DLL. The simplest way to ensure this is to make sure yapi.dll is located in the same directory as the executable file of your application.
15.2. Control of the Current function
Launch your Delphi environment, copy the yapi.dll DLL in a directory, create a new console application in the same directory, and copy-paste the piece of code below: program helloworld;
{$APPTYPE CONSOLE} uses
SysUtils,
Windows,
yocto_api,
yocto_current;
1
Actually, Borland provided free versions (for personal use) of Delphi 2006 and 2007. Look for them on the Internet, you may still be able to download them.
2
3
Delphi libraries are regularly tested with Delphi 5 and Delphi XE2.
4 www.yoctopuce.com/EN/libraries.php
Use the Tools / Environment options menu.
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15. Using Yocto-Amp with Delphi
Procedure usage () ; var
execname : string ; begin
execname := ExtractFileName ( paramstr ( 0 )) ; writeln ( execname+ ' <serial_number>' ) ; writeln ( execname+ ' <logical_name>' ) ; writeln ( execname+ ' any ' ) ; sleep ( 2500 ) ; halt ; end ;
Procedure die ( msg: string ) ; begin writeln ( msg + ' (check USB cable)' ) ; halt ; end ; var
errmsg : string ;
target : string ;
sensor : TYCurrent;
sensorDC : TYCurrent;
sensorAC : TYCurrent;
m : TyModule; begin if ( paramcount< 1 ) then usage () ;
target:= paramstr ( 1 ) ;
// Setup the API to use local USB devices
If ( yRegisterHub ( 'usb' , errmsg ) <> YAPI_SUCCESS ) Then begin
WriteLn ( 'RegisterHub error: ' + errmsg ) ; halt ;
End ; if ( target= 'any' ) then begin
// retreive any voltage sensor (can be AC or DC)
sensor := yFirstCurrent () ;
If sensor= nil Then Die ( 'No module connected' ) ; end else
sensor:= yFindCurrent ( target + '.current1' ) ;
m := nil ;
sensorDC := nil ;
sensorAC := nil ;
// we need to retreive both DC and AC voltage from the device.
If ( sensor.
isOnline ()) Then begin
m := sensor.
get_module () ;
sensorDC := yFindCurrent ( m.
get_serialNumber () + '.current1' ) ;
sensorAC := yFindCurrent ( m.
get_serialNumber () + '.current2' ) ; end else Die ( 'Module not connected' ) ;
// let's poll
repeat
If Not( m.
isOnline ()) Then Die ( 'Module not connected' ) ;
Write ( 'DC: ' + FloatToStr ( sensorDC.
get_currentValue ()) + ' mA ' ) ;
Write ( 'AC: ' + FloatToStr ( sensorAC.
get_currentValue ()) + ' mA ' ) ;
Writeln ( ' (press Ctrl-C to exit)' ) ;
ySleep ( 1000 , errmsg ) ; until ( false ) ; end .
There are only a few really important lines in this sample example. We will look at them in details.
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15. Using Yocto-Amp with Delphi
yocto_api and yocto_current
These two units provide access to the functions allowing you to manage Yoctopuce modules. yocto_api
must always be used, yocto_current
is necessary to manage modules containing a current sensor, such as Yocto-Amp.
yRegisterHub
The yRegisterHub
function initializes the Yoctopuce API and specifies where the modules should be looked for. When used with the parameter
'usb'
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI_SUCCESS
and errmsg
contains the error message.
yFindCurrent
The yFindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can also use logical names, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current := yFindCurrent ( "YAMPMK01123456 .
current1 " ) ; current := yFindCurrent ( "YAMPMK01123456 .
MyFunction " ) ; current := yFindCurrent ( "MyModule.
current1 " ) ; current := yFindCurrent ( "MyModule.
MyFunction " ) ; current := yFindCurrent ( "MyFunction" ) ; yFindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by corresponding module is present and in working order.
yFindCurrent
allows you to know if the
get_currentValue
The get_currentValue()
method of the object returned by yFindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
15.3. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
program modulecontrol;
{$APPTYPE CONSOLE} uses
SysUtils,
yocto_api; const
serial = 'YAMPMK01-123456' ;
// use serial number or logical name
procedure refresh ( module:Tymodule ) ; begin if ( module.
isOnline ()) then begin
Writeln ( '' ) ;
Writeln ( 'Serial : ' + module.
get_serialNumber ()) ;
Writeln ( 'Logical name : ' + module.
get_logicalName ()) ;
Writeln ( 'Luminosity : ' + intToStr ( module.
get_luminosity ())) ;
Write ( 'Beacon :' ) ; if ( module.
get_beacon () =Y_BEACON_ON ) then Writeln ( 'on' ) else Writeln ( 'off' ) ;
Writeln ( 'uptime : ' + intToStr ( module.
get_upTime () div 1000 ) + 's' ) ;
Writeln ( 'USB current : ' + intToStr ( module.
get_usbCurrent ()) + 'mA' ) ;
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15. Using Yocto-Amp with Delphi
82
Writeln ( 'Logs : ' ) ;
Writeln ( module.
get_lastlogs ()) ;
Writeln ( '' ) ;
Writeln ( 'r : refresh / b:beacon ON / space : beacon off' ) ; end else Writeln ( 'Module not connected (check identification and USB cable)' ) ; end ; procedure beacon ( module:Tymodule;state: integer ) ; begin
module.
set_beacon ( state ) ;
refresh ( module ) ; end ; var
module : TYModule;
c : char ;
errmsg : string ; begin
// Setup the API to use local USB devices
if yRegisterHub ( 'usb' , errmsg ) <>YAPI_SUCCESS then begin
Write ( 'RegisterHub error: ' +errmsg ) ; exit ; end ;
module := yFindModule ( serial ) ;
refresh ( module ) ; repeat read ( c ) ; case c of
'r' : refresh ( module ) ;
'b' : beacon ( module,Y_BEACON_ON ) ;
' ' : beacon ( module,Y_BEACON_OFF ) ; end ; until c = 'x' ; end .
Each property xxx
of the module can be read thanks to a method of type get_xxxx()
, and properties which are not read-only can be modified with the help of the more details regarding the used functions, refer to the API chapters.
set_xxx()
method. For
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding set_xxx()
function. However, this modification is performed only in the random access memory
(RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the revertFromFlash()
method. The short example below allows you to modify the logical name of a module.
program savesettings;
{$APPTYPE CONSOLE} uses
SysUtils,
yocto_api; const
serial = 'YAMPMK01-123456' ;
// use serial number or logical name
var
module : TYModule;
errmsg : string ;
newname : string ; begin
// Setup the API to use local USB devices
if yRegisterHub ( 'usb' , errmsg ) <>YAPI_SUCCESS then begin
Write ( 'RegisterHub error: ' +errmsg ) ; exit ;
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15. Using Yocto-Amp with Delphi
end ;
module := yFindModule ( serial ) ; if (not( module.
isOnline )) then begin writeln ( 'Module not connected (check identification and USB cable)' ) ; exit ; end ;
Writeln ( 'Current logical name : ' +module.
get_logicalName ()) ;
Write ( 'Enter new name : ' ) ;
Readln ( newname ) ; if (not( yCheckLogicalName ( newname ))) then begin
Writeln ( 'invalid logical name' ) ; exit ; end ;
module.
set_logicalName ( newname ) ;
module.
saveToFlash () ;
Writeln ( 'logical name is now : ' +module.
get_logicalName ()) ; end .
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the saveToFlash()
function only 100000 times in the life of the module. Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the yFirstModule()
function which returns the first module found. Then, you only need to call the nextModule()
function of this object to find the following modules, and this as long as the returned value is not nil
. Below a short example listing the connected modules.
program inventory;
{$APPTYPE CONSOLE} uses
SysUtils,
yocto_api; var
module : TYModule;
errmsg : string ; begin
// Setup the API to use local USB devices
if yRegisterHub ( 'usb' , errmsg ) <>YAPI_SUCCESS then begin
Write ( 'RegisterHub error: ' +errmsg ) ; exit ; end ;
Writeln ( 'Device list' ) ;
module := yFirstModule () ; while module<> nil do begin
Writeln ( module.
get_serialNumber () + ' (' +module.
get_productName () + ')' ) ;
module := module.
nextModule () ; end ; end .
15.4. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help
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15. Using Yocto-Amp with Delphi
you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
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16. Using the Yocto-Amp with Python
Python is an interpreted object oriented language developed by Guido van Rossum. Among its advantages is the fact that it is free, and the fact that it is available for most platforms, Windows as well as UNIX. It is an ideal language to write small scripts on a napkin. The Yoctopuce library is compatible with Python 2.6+ and 3+. It works under Windows, Mac OS X, and Linux, Intel as well as
ARM. The library was tested with Python 2.6 and Python 3.2. Python interpreters are available on the
Python web site
1
.
16.1. Source files
The Yoctopuce library classes
2
for Python that you will use are provided as source files. Copy all the content of the Sources directory in the directory of your choice and add this directory to the
PYTHONPATH environment variable. If you use an IDE to program in Python, refer to its documentation to configure it so that it automatically finds the API source files.
16.2. Dynamic library
A section of the low-level library is written in C, but you should not need to interact directly with it: it is provided as a DLL under Windows, as a .so files under UNIX, and as a .dylib file under Mac OS X.
Everything was done to ensure the simplest possible interaction from Python: the distinct versions of the dynamic library corresponding to the distinct operating systems and architectures are stored in the cdll directory. The API automatically loads the correct file during its initialization. You should not have to worry about it.
If you ever need to recompile the dynamic library, its complete source code is located in the
Yoctopuce C++ library.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.
16.3. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a Python code snipplet to use the Current function.
1 http://www.python.org/download/
2 www.yoctopuce.com/EN/libraries.php
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16. Using the Yocto-Amp with Python
[ ...
] errmsg=YRefParam ()
#Get access to your device, connected locally on USB for instance
YAPI.
RegisterHub ( "usb" ,errmsg ) current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" )
# Hot-plug is easy: just check that the device is online
if current.
isOnline () :
#Use current.get_currentValue()
...
[ ...
]
Let's look at these lines in more details.
YAPI.RegisterHub
The yAPI.RegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. When used with the parameter
"usb"
, it will use the modules locally connected to the computer running the library. If the initialization does not succeed, this function returns a value different from
YAPI.SUCCESS
and errmsg
contains the error message.
YCurrent.FindCurrent
The
YCurrent.FindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) current = YCurrent.
FindCurrent ( "YAMPMK01-123456.MyFunction" ) current = YCurrent.
FindCurrent ( "MyModule.current1" ) current = YCurrent.
FindCurrent ( "MyModule.MyFunction" ) current = YCurrent.
FindCurrent ( "MyFunction" )
YCurrent.FindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by
YCurrent.FindCurrent
allows you to know if the corresponding module is present and in working order.
get_currentValue
The get_currentValue()
method of the object returned by
YCurrent.FindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Launch Python and open the corresponding sample script provided in the directory Examples/Doc-
GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all side materials needed to make it work nicely as a small demo.
#!/usr/bin/python
# -*- coding: utf-8 -*-
import os , sys from yocto_api import * from yocto_current import *
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16. Using the Yocto-Amp with Python
def usage () :
scriptname = os .
path .
basename ( sys .
argv [ 0 ]) print( "Usage:" ) print( scriptname+ ' <serial_number>' ) print( scriptname+ ' <logical_name>' ) print( scriptname+ ' any ' ) sys .
exit () def die ( msg ) : sys .
exit ( msg+ ' (check USB cable)' ) errmsg=YRefParam () if len ( sys .
argv ) < 2 : usage () target= sys .
argv [ 1 ]
# Setup the API to use local USB devices
if YAPI.
RegisterHub ( "usb" , errmsg ) != YAPI.
SUCCESS : sys .
exit ( "init error" +errmsg.
value ) if target== 'any' :
# retreive any voltage sensor (can be AC or DC)
sensor = YCurrent.
FirstCurrent () if sensor is None :
die ( 'No module connected' ) else :
sensor= YCurrent.
FindCurrent ( target + '.current1' )
# we need to retreive both DC and AC voltage from the device.
if sensor.
isOnline () :
m = sensor.
get_module ()
sensorDC = YCurrent.
FindCurrent ( m.
get_serialNumber () + '.current1' )
sensorAC = YCurrent.
FindCurrent ( m.
get_serialNumber () + '.current2' ) else :
die ( 'Module not connected' )
# let's poll
while True : if not m.
isOnline () : die ( 'Module not connected' ) print( 'DC: ' + str ( sensorDC.
get_currentValue ()) + ' mA ' + \
'AC: ' + str ( sensorAC.
get_currentValue ()) + ' mA ' ) print( ' (press Ctrl-C to exit)' )
YAPI.
Sleep ( 1000 , errmsg )
16.4. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
#!/usr/bin/python
# -*- coding: utf-8 -*-
import os , sys from yocto_api import * def usage () : sys .
exit ( "usage: demo <serial or logical name> [ON/OFF]" ) errmsg =YRefParam () if YAPI.
RegisterHub ( "usb" , errmsg ) != YAPI.
SUCCESS : sys .
exit ( "RegisterHub error: " + str ( errmsg )) if len ( sys .
argv ) < 2 : usage () m = YModule.
FindModule ( sys .
argv [ 1 ])
## use serial or logical name
if m.
isOnline () : if len ( sys .
argv ) > 2 : if sys .
argv [ 2 ] .
upper () == "ON" : m.
set_beacon ( YModule.
BEACON_ON ) if sys .
argv [ 2 ] .
upper () == "OFF" : m.
set_beacon ( YModule.
BEACON_OFF )
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16. Using the Yocto-Amp with Python
88
print( "serial: " + m.
get_serialNumber ()) print( "logical name: " + m.
get_logicalName ()) print( "luminosity: " + str ( m.
get_luminosity ())) if m.
get_beacon () == YModule.
BEACON_ON : print( "beacon: ON" ) else : print( "beacon: OFF" ) print( "upTime: " + str ( m.
get_upTime () / 1000 ) + " sec" ) print( "USB current: " + str ( m.
get_usbCurrent ()) + " mA" ) print( "logs: \n" + m.
get_lastLogs ()) else : print( sys .
argv [ 1 ] + " not connected (check identification and USB cable)" )
Each property xxx
of the module can be read thanks to a method of type
YModule.get_xxxx()
, and properties which are not read-only can be modified with the help of the
YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding
YModule.set_xxx()
function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the
YModule.saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the
YModule.revertFromFlash()
The short example below allows you to modify the logical name of a module.
method.
#!/usr/bin/python
# -*- coding: utf-8 -*-
import os , sys from yocto_api import * def usage () : sys .
exit ( "usage: demo <serial or logical name> <new logical name>" ) if len ( sys .
argv ) != 3 : usage () errmsg =YRefParam () if YAPI.
RegisterHub ( "usb" , errmsg ) != YAPI.
SUCCESS : sys .
exit ( "RegisterHub error: " + str ( errmsg )) m = YModule.
FindModule ( sys .
argv [ 1 ])
# use serial or logical name
if m.
isOnline () :
newname = sys .
argv [ 2 ] if not YAPI.
CheckLogicalName ( newname ) : sys .
exit ( "Invalid name (" + newname + ")" )
m.
set_logicalName ( newname )
m.
saveToFlash ()
# do not forget this
print ( "Module: serial= " + m.
get_serialNumber () + " / name= " + m.
get_logicalName ()) else : sys .
exit ( "not connected (check identification and USB cable" )
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the
YModule.saveToFlash()
function only 100000 times in the life of the module.
Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the
YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null
. Below a short example listing the connected modules.
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16. Using the Yocto-Amp with Python
#!/usr/bin/python
# -*- coding: utf-8 -*-
import os , sys from yocto_api import * errmsg=YRefParam ()
# Setup the API to use local USB devices
if YAPI.
RegisterHub ( "usb" , errmsg ) != YAPI.
SUCCESS : sys .
exit ( "init error" + str ( errmsg )) print( 'Device list' ) module = YModule.
FirstModule () while module is not None : print( module.
get_serialNumber () + ' (' +module.
get_productName () + ')' )
module = module.
nextModule ()
16.5. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software. The only way to prevent this is to implement one of the two error handling techniques described below.
The method recommended by most programming languages for unpredictable error handling is the use of exceptions. By default, it is the behavior of the Yoctopuce library. If an error happens while you try to access a module, the library throws an exception. In this case, there are three possibilities:
• If your code catches the exception and handles it, everything goes well.
• If your program is running in debug mode, you can relatively easily determine where the problem happened and view the explanatory message linked to the exception.
• Otherwise... the exception makes your program crash, bang!
As this latest situation is not the most desirable, the Yoctopuce library offers another possibility for error handling, allowing you to create a robust program without needing to catch exceptions at every line of code. You simply need to call the yDisableExceptions()
function to commute the library to a mode where exceptions for all the functions are systematically replaced by specific return values, which can be tested by the caller when necessary. For each function, the name of each return value in case of error is systematically documented in the library reference. The name always follows the same logic: a get_state()
method returns a
Y_STATE_INVALID
value, a get_currentValue
method returns a
Y_CURRENTVALUE_INVALID
value, and so on. In any case, the returned value is of the expected type and is not a null pointer which would risk crashing your program. At worst, if you display the value without testing it, it will be outside the expected bounds for the returned value. In the case of functions which do not normally return information, the return value is
YAPI_SUCCESS
if everything went well, and a different error code in case of failure.
When you work without exceptions, you can obtain an error code and an error message explaining the source of the error. You can request them from the object which returned the error, calling the errType()
and errMessage()
methods. Their returned values contain the same information as in the exceptions when they are active.
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17. Using the Yocto-Amp with Java
Java is an object oriented language created by Sun Microsystem. Beside being free, its main strength is its portability. Unfortunately, this portability has an excruciating price. In Java, hardware abstraction is so high that it is almost impossible to work directly with the hardware. Therefore, the
Yoctopuce API does not support native mode in regular Java. The Java API needs a Virtual Hub to communicate with Yoctopuce devices.
17.1. Getting ready
Go to the Yoctopuce web site and download the following items:
• The Java programming library
• The VirtualHub software
2
1
for Windows, Mac OS X or Linux, depending on your OS
The library is available as source files as well as a jar file. Decompress the library files in a folder of your choice, connect your modules, run the VirtualHub software, and you are ready to start your first tests. You do not need to install any driver.
In order to keep them simple, all the examples provided in this documentation are console applications. Naturally, the libraries function in a strictly identical manner if you integrate them in an application with a graphical interface.
17.2. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a Java code snippet to use the Current function.
[ ...
]
// Get access to your device, connected locally on USB for instance
YAPI.
RegisterHub ( "127.0.0.1" ) ; current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) ;
// Hot-plug is easy: just check that the device is online
if ( current.
isOnline ())
{
//Use current.get_currentValue()
...
}
1 www.yoctopuce.com/EN/libraries.php
2 www.yoctopuce.com/EN/virtualhub.php
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17. Using the Yocto-Amp with Java
92
[ ...
]
Let us look at these lines in more details.
YAPI.RegisterHub
The yAPI.RegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the Virtual Hub able to see the devices. If the initialization does not succeed, an exception is thrown.
YCurrent.FindCurrent
The
YCurrent.FindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) current = YCurrent.
FindCurrent ( "YAMPMK01-123456.MyFunction" ) current = YCurrent.
FindCurrent ( "MyModule.current1" ) current = YCurrent.
FindCurrent ( "MyModule.MyFunction" ) current = YCurrent.
FindCurrent ( "MyFunction" )
YCurrent.FindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by
YCurrent.FindCurrent
allows you to know if the corresponding module is present and in working order.
get_currentValue
The get_currentValue()
method of the object returned by
YCurrent.FindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
A real example
Launch you Java environment and open the corresponding sample project provided in the directory
Examples/Doc-GettingStarted-Yocto-Amp of the Yoctopuce library.
In this example, you will recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.
import com.yoctopuce.YoctoAPI.* ; public class Demo { public static void demo ( String ac_hardwareid, String dc_hardwareid )
{
// we need to retreive both DC and AC voltage from the device.
YCurrent sensorDC = YCurrent.
FindCurrent ( dc_hardwareid ) ;
YCurrent sensorAC = YCurrent.
FindCurrent ( ac_hardwareid ) ; while ( true ) { try {
System .
out .
println ( "DC: " + sensorDC.
get_currentValue () + " mA " ) ;
System .
out .
println ( "AC: " + sensorAC.
get_currentValue () + " mA " ) ;
System .
out .
println ( " (press Ctrl-C to exit)" ) ;
YAPI.
Sleep ( 1000 ) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Module " +sensorDC.
module () + " is not connected" ) ; return ;
}
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17. Using the Yocto-Amp with Java
}
} public static void main ( String [] args )
{ try {
// setup the API to use local VirtualHub
YAPI.
RegisterHub ( "127.0.0.1" ) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Cannot contact VirtualHub on 127.0.0.1 (" + ex.
getLocalizedMessage () + ")" ) ;
System .
out .
println ( "Ensure that the VirtualHub application is running" ) ;
System .
exit ( 1 ) ;
}
String serial= "" ; if ( args.
length > 0 ) {
serial = args [ 0 ] ;
} else {
YCurrent sensor = YCurrent.
FirstCurrent () ; if ( sensor == null ) {
System .
out .
println ( "No module connected (check USB cable)" ) ;
System .
exit ( 1 ) ;
} try {
serial = sensor.
module () .
get_serialNumber () ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "No module connected (check USB cable)" ) ;
System .
exit ( 1 ) ;
}
}
Demo.
demo ( serial + ".current1" ,serial + ".current2" ) ;
YAPI.
FreeAPI () ;
}
}
17.3. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
import com.yoctopuce.YoctoAPI.* ; import java.util.logging.Level
; import java.util.logging.Logger
; public class Demo { public static void main ( String [] args )
{ try {
// setup the API to use local VirtualHub
YAPI.
RegisterHub ( "127.0.0.1" ) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Cannot contact VirtualHub on 127.0.0.1 (" + ex.
getLocalizedMessage () + ")" ) ;
System .
out .
println ( "Ensure that the VirtualHub application is running" ) ;
System .
exit ( 1 ) ;
}
System .
out .
println ( "usage: demo [serial or logical name] [ON/OFF]" ) ;
YModule module; if ( args.
length == 0 ) {
module = YModule.
FirstModule () ; if ( module == null ) {
System .
out .
println ( "No module connected (check USB cable)" ) ;
System .
exit ( 1 ) ;
}
} else {
module = YModule.
FindModule ( args [ 0 ]) ;
// use serial or logical name
}
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17. Using the Yocto-Amp with Java
94
try { if ( args.
length > 1 ) { if ( args [ 1 ] .
equalsIgnoreCase ( "ON" )) {
module.
setBeacon ( YModule.
BEACON_ON ) ;
} else {
module.
setBeacon ( YModule.
BEACON_OFF ) ;
}
}
System .
out .
println ( "serial: " + module.
get_serialNumber ()) ;
System .
out .
println ( "logical name: " + module.
get_logicalName ()) ;
System .
out .
println ( "luminosity: " + module.
get_luminosity ()) ; if ( module.
get_beacon () == YModule.
BEACON_ON ) {
System .
out .
println ( "beacon: ON" ) ;
} else {
System .
out .
println ( "beacon: OFF" ) ;
}
System .
out .
println ( "upTime: " + module.
get_upTime () / 1000 + " sec" ) ;
System .
out .
println ( "USB current: " + module.
get_usbCurrent () + " mA" ) ;
System .
out .
println ( "logs:
\n"
+ module.
get_lastLogs ()) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( args [ 1 ] + " not connected (check identification and USB cable)" ) ;
}
YAPI.
FreeAPI () ;
}
}
Each property xxx
of the module can be read thanks to a method of type
YModule.get_xxxx()
, and properties which are not read-only can be modified with the help of the
YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding
YModule.set_xxx()
function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the
YModule.saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the
YModule.revertFromFlash()
The short example below allows you to modify the logical name of a module.
method. import com.yoctopuce.YoctoAPI.* ; public class Demo { public static void main ( String [] args )
{ try {
// setup the API to use local VirtualHub
YAPI.
RegisterHub ( "127.0.0.1" ) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Cannot contact VirtualHub on 127.0.0.1 (" + ex.
getLocalizedMessage () + ")" ) ;
System .
out .
println ( "Ensure that the VirtualHub application is running" ) ;
System .
exit ( 1 ) ;
} if ( args.
length != 2 ) {
System .
out .
println ( "usage: demo <serial or logical name> <new logical name>" ) ;
System .
exit ( 1 ) ;
}
YModule m;
String newname;
m = YModule.
FindModule ( args [ 0 ]) ;
// use serial or logical name
try {
newname = args [ 1 ] ; if ( !YAPI.
CheckLogicalName ( newname ))
{
System .
out .
println ( "Invalid name (" + newname + ")" ) ;
System .
exit ( 1 ) ;
}
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17. Using the Yocto-Amp with Java
m.
set_logicalName ( newname ) ;
m.
saveToFlash () ;
// do not forget this
System .
out .
println ( "Module: serial= " + m.
get_serialNumber ()) ;
System .
out .
println ( " / name= " + m.
get_logicalName ()) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Module " + args [ 0 ] + "not connected (check identification and USB cable)" ) ;
System .
out .
println ( ex.
getMessage ()) ;
System .
exit ( 1 ) ;
}
YAPI.
FreeAPI () ;
}
}
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the
YModule.saveToFlash()
function only 100000 times in the life of the module.
Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the
YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null
. Below a short example listing the connected modules.
import com.yoctopuce.YoctoAPI.* ; public class Demo { public static void main ( String [] args )
{ try {
// setup the API to use local VirtualHub
YAPI.
RegisterHub ( "127.0.0.1" ) ;
} catch ( YAPI_Exception ex ) {
System .
out .
println ( "Cannot contact VirtualHub on 127.0.0.1 (" + ex.
getLocalizedMessage () + ")" ) ;
System .
out .
println ( "Ensure that the VirtualHub application is running" ) ;
System .
exit ( 1 ) ;
}
System .
out .
println ( "Device list" ) ;
YModule module = YModule.
FirstModule () ; while ( module != null ) { try {
System .
out .
println ( module.
get_serialNumber () + " (" + module.
get_productName () + ")" ) ;
} catch ( YAPI_Exception ex ) { break ;
}
module = module.
nextModule () ;
}
YAPI.
FreeAPI () ;
}
}
17.4. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
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17. Using the Yocto-Amp with Java
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to could crash the software.
isOnline
and which
In the Java API, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash as soon as you unplug a device.
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18. Using the Yocto-Amp with Android
To tell the truth, Android is not a programming language, it is an operating system developed by
Google for mobile appliances such as smart phones and tablets. But it so happens that under
Android everything is programmed with the same programming language: Java. Nevertheless, the programming paradigms and the possibilities to access the hardware are slightly different from classical Java, and this justifies a separate chapter on Android programming.
18.1. Native access and VirtualHub
In the opposite to the classical Java API, the Java for Android API can access USB modules natively.
However, as there is no VirtualHub running under Android, it is not possible to remotely control
Yoctopuce modules connected to a machine under Android. Naturally, the Java for Android API remains perfectly able to connect itself to a VirtualHub running on another OS.
18.2. Getting ready
Go to the Yoctopuce web site and download the Java for Android programming library
1
. The library is available as source files, and also as a jar file. Connect your modules, decompress the library files in the directory of your choice, and configure your Android programming environment so that it can find them.
To keep them simple, all the examples provided in this documentation are snippets of Android applications. You must integrate them in your own Android applications to make them work.
However, your can find complete applications in the examples provided with the Java for Android library.
18.3. Compatibility
In an ideal world, you would only need to have a smart phone running under Android to be able to make Yoctopuce modules work. Unfortunately, it is not quite so in the real world. A machine running under Android must fulfil to a few requirements to be able to manage Yoctopuce USB modules natively.
1 www.yoctopuce.com/EN/libraries.php
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18. Using the Yocto-Amp with Android
Android 4.x
Android 4.0 (api 14) and following are officially supported. Theoretically, support of USB host functions since Android 3.1. But be aware that the Yoctopuce Java for Android API is regularly tested only from Android 4 onwards.
USB host support
Naturally, not only must your machine have a USB port, this port must also be able to run in host mode. In host mode, the machine literally takes control of the devices which are connected to it. The
USB ports of a desktop computer, for example, work in host mode. The opposite of the host mode is the device mode. USB keys, for instance, work in device mode: they must be controlled by a host.
Some USB ports are able to work in both modes, they are OTG (On The Go) ports. It so happens that many mobile devices can only work in device mode: they are designed to be connected to a charger or a desktop computer, and nothing else. It is therefore highly recommended to pay careful attention to the technical specifications of a product working under Android before hoping to make
Yoctopuce modules work with it.
Unfortunately, having a correct version of Android and USB ports working in host mode is not enough to guaranty that Yoctopuce modules will work well under Android. Indeed, some manufacturers configure their Android image so that devices other than keyboard and mass storage are ignored, and this configuration is hard to detect. As things currently stand, the best way to know if a given
Android machine works with Yoctopuce modules consists in trying.
Supported hardware
The library is tested and validated on the following machines:
• Samsung Galaxy S3
• Samsung Galaxy Note 2
• Google Nexus 5
• Google Nexus 7
• Acer Iconia Tab A200
• Asus Tranformer Pad TF300T
• Kurio 7
If your Android machine is not able to control Yoctopuce modules natively, you still have the possibility to remotely control modules driven by a VirtualHub on another OS, or a YoctoHub
2
.
18.4. Activating the USB port under Android
By default, Android does not allow an application to access the devices connected to the USB port.
To enable your application to interact with a Yoctopuce module directly connected on your tablet on a
USB port, a few additional steps are required. If you intend to interact only with modules connected on another machine through the network, you can ignore this section.
In your
AndroidManifest.xml
, you must declare using the "USB Host" functionality by adding the
<uses-feature android:name="android.hardware.usb.host" />
tag in the manifest
section.
<manifest ...>
...
<uses-feature android:name= "android.hardware.usb.host" />;
...
</manifest>
When first accessing a Yoctopuce module, Android opens a window to inform the user that the application is going to access the connected module. The user can deny or authorize access to the device. If the user authorizes the access, the application can access the connected device as long as
98
2
Yoctohubs are a plug and play way to add network connectivity to your Yoctopuce devices. more info on http:// www.yoctopuce.com/EN/products/category/extensions-and-networking
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18. Using the Yocto-Amp with Android
it stays connected. To enable the Yoctopuce library to correctly manage these authorizations, your must provide a pointer on the application context by calling the EnableUSBHost method of the YAPI class before the first USB access. This function takes as arguments an object of the android.content.Context
class (or of a subclass). As the Activity class is a subclass of
Context
, it is simpler to call
YAPI.EnableUSBHost(this);
in the method onCreate
of your application. If the object passed as parameter is not of the correct type, a exception is generated.
YAPI_Exception
...
@Override public void onCreate ( Bundle savedInstanceState ) { super .
onCreate ( savedInstanceState ) ; try {
// Pass the application Context to the Yoctopuce Library
YAPI.
EnableUSBHost (this) ;
} catch ( YAPI_Exception e ) {
Log.
e ( "Yocto" ,e.
getLocalizedMessage ()) ;
}
}
...
Autorun
It is possible to register your application as a default application for a USB module. In this case, as soon as a module is connected to the system, the application is automatically launched. You must add <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"/> in the section <intent-filter> of the main activity. The section <activity> must have a pointer to an XML file containing the list of USB modules which can run the application.
<manifest xmlns:android= "http://schemas.android.com/apk/res/android"
...
<uses-feature android:name= "android.hardware.usb.host" />
...
<application ... >
<activity
android:name= ".MainActivity" >
<intent-filter>
<action android:name= "android.intent.action.MAIN" />
<action android:name= "android.hardware.usb.action.USB_DEVICE_ATTACHED" />
<category android:name= "android.intent.category.LAUNCHER" />
</intent-filter>
<meta-data
android:name= "android.hardware.usb.action.USB_DEVICE_ATTACHED"
android:resource= "@xml/device_filter" />
</activity>
</application>
</manifest>
The XML file containing the list of modules allowed to run the application must be saved in the res/ xml directory. This file contains a list of USB vendorId and deviceID in decimal. The following example runs the application as soon as a Yocto-Relay or a YoctoPowerRelay is connected. You can find the vendorID and the deviceID of Yoctopuce modules in the characteristics section of the documentation.
<?xml version= "1.0" encoding= "utf-8" ?>
<resources>
<usb-device vendor-id= "9440" product-id= "12" />
<usb-device vendor-id= "9440" product-id= "13" />
</resources>
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18.5. Control of the Current function
A few lines of code are enough to use a Yocto-Amp. Here is the skeleton of a Java code snippet to use the Current function.
[ ...
]
// Retrieving the object representing the module (connected here locally by USB)
YAPI.
EnableUSBHost (this) ;
YAPI.
RegisterHub ( "usb" ) ; current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) ;
// Hot-plug is easy: just check that the device is online
if ( current.
isOnline ())
{
//Use current.get_currentValue()
...
}
[ ...
]
Let us look at these lines in more details.
YAPI.EnableUSBHost
The
YAPI.EnableUSBHost
function initializes the API with the Context of the current application.
This function takes as argument an object of the android.content.Context
class (or of a subclass). If you intend to connect your application only to other machines through the network, this function is facultative.
YAPI.RegisterHub
The yAPI.RegisterHub
function initializes the Yoctopuce API and indicates where the modules should be looked for. The parameter is the address of the virtual hub able to see the devices. If the string "usb" is passed as parameter, the API works with modules locally connected to the machine. If the initialization does not succeed, an exception is thrown.
YCurrent.FindCurrent
The
YCurrent.FindCurrent
function allows you to find a current sensor from the serial number of the module on which it resides and from its function name. You can use logical names as well, as long as you have initialized them. Let us imagine a Yocto-Amp module with serial number
YAMPMK01-123456 which you have named "MyModule", and for which you have given the current1 function the name "MyFunction". The following five calls are strictly equivalent, as long as
"MyFunction" is defined only once.
current = YCurrent.
FindCurrent ( "YAMPMK01-123456.current1" ) current = YCurrent.
FindCurrent ( "YAMPMK01-123456.MyFunction" ) current = YCurrent.
FindCurrent ( "MyModule.current1" ) current = YCurrent.
FindCurrent ( "MyModule.MyFunction" ) current = YCurrent.
FindCurrent ( "MyFunction" )
YCurrent.FindCurrent
returns an object which you can then use at will to control the current sensor.
isOnline
The isOnline()
method of the object returned by
YCurrent.FindCurrent
know if the corresponding module is present and in working order.
allows you to
get_currentValue
The get_currentValue()
method of the object returned by
YCurrent.FindCurrent
allows you to obtain the current, as measured by the sensor. The returned value is a number, directly representing the value in mA.
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A real example
Launch you Java environment and open the corresponding sample project provided in the directory
Examples//Doc-Examples of the Yoctopuce library.
In this example, you can recognize the functions explained above, but this time used with all the side materials needed to make it work nicely as a small demo.
package com.yoctopuce.doc_examples
; import android.app.Activity
; import android.os.Bundle
; import android.os.Handler
; import android.view.View
; import android.widget.AdapterView
; import android.widget.AdapterView.OnItemSelectedListener
; import android.widget.ArrayAdapter
; import android.widget.Spinner
; import android.widget.TextView
; import com.yoctopuce.YoctoAPI.YAPI
; import com.yoctopuce.YoctoAPI.YAPI_Exception
; import com.yoctopuce.YoctoAPI.YCurrent
; import com.yoctopuce.YoctoAPI.YModule
; public class GettingStarted_Yocto_Amp extends Activity implements OnItemSelectedListener
{ private ArrayAdapter<String> aa; private String serial = "" ; private Handler handler = null ;
@Override public void onCreate ( Bundle savedInstanceState )
{ super .
onCreate ( savedInstanceState ) ;
setContentView ( R.
layout .
gettingstarted_yocto_amp ) ;
Spinner my_spin = ( Spinner ) findViewById ( R.
id .
spinner1 ) ;
my_spin.
setOnItemSelectedListener (this) ;
aa = new ArrayAdapter<String> (this , android.
R .
layout .
simple_spinner_item ) ;
aa.
setDropDownViewResource ( android.
R .
layout .
simple_spinner_dropdown_item ) ;
my_spin.
setAdapter ( aa ) ;
handler = new Handler () ;
}
@Override protected void onStart ()
{ super .
onStart () ; try {
aa.
clear () ;
YAPI.
EnableUSBHost (this) ;
YAPI.
RegisterHub ( "usb" ) ;
YModule module = YModule.
FirstModule () ; while ( module != null ) { if ( module.
get_productName () .
equals ( "Yocto-Amp" )) {
String serial = module.
get_serialNumber () ;
aa.
add ( serial ) ;
}
module = module.
nextModule () ;
}
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
aa.
notifyDataSetChanged () ;
handler.
postDelayed ( r, 500 ) ;
}
@Override protected void onStop ()
{ super .
onStop () ;
handler.
removeCallbacks ( r ) ;
YAPI.
FreeAPI () ;
}
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18. Using the Yocto-Amp with Android
@Override public void onItemSelected ( AdapterView<?> parent, View view, int pos, long id )
{
serial = parent.
getItemAtPosition ( pos ) .
toString () ;
}
@Override public void onNothingSelected ( AdapterView<?> arg0 )
{
} final Runnable r = new Runnable ()
{ public void run ()
{ if ( serial != null ) {
YCurrent dc_sensor = YCurrent.
FindCurrent ( serial + ".current1" ) ; try {
TextView view = ( TextView ) findViewById ( R.
id .
dcfield ) ;
view.
setText ( String .
format ( "%.1f %s" , dc_sensor.
getCurrentValue () , dc_sensor.
getUnit ())) ;
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
YCurrent ac_sensor = YCurrent.
FindCurrent ( serial + ".current2" ) ; try {
TextView view = ( TextView ) findViewById ( R.
id .
acfield ) ;
view.
setText ( String .
format ( "%.1f %s" , ac_sensor.
getCurrentValue () , ac_sensor.
getUnit ())) ;
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
}
handler.
postDelayed (this , 1000 ) ;
}
} ;
}
18.6. Control of the module part
Each module can be controlled in a similar manner, you can find below a simple sample program displaying the main parameters of the module and enabling you to activate the localization beacon.
package com.yoctopuce.doc_examples
; import android.app.Activity
; import android.os.Bundle
; import android.util.Log
; import android.view.View
; import android.widget.AdapterView
; import android.widget.AdapterView.OnItemSelectedListener
; import android.widget.ArrayAdapter
; import android.widget.Spinner
; import android.widget.Switch
; import android.widget.TextView
; import com.yoctopuce.YoctoAPI.YAPI
; import com.yoctopuce.YoctoAPI.YAPI_Exception
; import com.yoctopuce.YoctoAPI.YModule
; public class ModuleControl extends Activity implements OnItemSelectedListener
{ private ArrayAdapter<String> aa; private YModule module = null ;
@Override public void onCreate ( Bundle savedInstanceState )
{ super .
onCreate ( savedInstanceState ) ;
setContentView ( R.
layout .
modulecontrol ) ;
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Spinner my_spin = ( Spinner ) findViewById ( R.
id .
spinner1 ) ;
my_spin.
setOnItemSelectedListener (this) ;
aa = new ArrayAdapter<String> (this , android.
R .
layout .
simple_spinner_item ) ;
aa.
setDropDownViewResource ( android.
R .
layout .
simple_spinner_dropdown_item ) ;
my_spin.
setAdapter ( aa ) ;
}
@Override protected void onStart ()
{ super .
onStart () ; try {
aa.
clear () ;
YAPI.
EnableUSBHost (this) ;
YAPI.
RegisterHub ( "usb" ) ;
YModule r = YModule.
FirstModule () ; while ( r != null ) {
String hwid = r.
get_hardwareId () ;
aa.
add ( hwid ) ;
r = r.
nextModule () ;
}
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
// refresh Spinner with detected relay
aa.
notifyDataSetChanged () ;
}
@Override protected void onStop ()
{ super .
onStop () ;
YAPI.
FreeAPI () ;
} private void DisplayModuleInfo ()
{
TextView field; if ( module == null ) return ; try {
field = ( TextView ) findViewById ( R.
id .
serialfield ) ;
field.
setText ( module.
getSerialNumber ()) ;
field = ( TextView ) findViewById ( R.
id .
logicalnamefield ) ;
field.
setText ( module.
getLogicalName ()) ;
field = ( TextView ) findViewById ( R.
id .
luminosityfield ) ;
field.
setText ( String .
format ( "%d%%" , module.
getLuminosity ())) ;
field = ( TextView ) findViewById ( R.
id .
uptimefield ) ;
field.
setText ( module.
getUpTime () / 1000 + " sec" ) ;
field = ( TextView ) findViewById ( R.
id .
usbcurrentfield ) ;
field.
setText ( module.
getUsbCurrent () + " mA" ) ;
Switch sw = (Switch) findViewById ( R.
id .
beaconswitch ) ;
Log.
d ( "switch" , "beacon" + module.
get_beacon ()) ;
sw.
setChecked ( module.
getBeacon () == YModule.
BEACON_ON ) ;
field = ( TextView ) findViewById ( R.
id .
logs ) ;
field.
setText ( module.
get_lastLogs ()) ;
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
}
@Override public void onItemSelected ( AdapterView<?> parent, View view, int pos, long id )
{
String hwid = parent.
getItemAtPosition ( pos ) .
toString () ;
module = YModule.
FindModule ( hwid ) ;
DisplayModuleInfo () ;
}
@Override public void onNothingSelected ( AdapterView<?> arg0 )
{
} public void refreshInfo ( View view )
{
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18. Using the Yocto-Amp with Android
DisplayModuleInfo () ;
} public void toggleBeacon ( View view )
{ if ( module == null ) return ; boolean on = ((Switch) view ) .
isChecked () ; try { if ( on ) {
module.
setBeacon ( YModule.
BEACON_ON ) ;
} else {
module.
setBeacon ( YModule.
BEACON_OFF ) ;
}
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
}
}
Each property xxx
of the module can be read thanks to a method of type
YModule.get_xxxx()
, and properties which are not read-only can be modified with the help of the
YModule.set_xxx() method. For more details regarding the used functions, refer to the API chapters.
Changing the module settings
When you want to modify the settings of a module, you only need to call the corresponding
YModule.set_xxx()
function. However, this modification is performed only in the random access memory (RAM) of the module: if the module is restarted, the modifications are lost. To memorize them persistently, it is necessary to ask the module to save its current configuration in its permanent memory. To do so, use the
YModule.saveToFlash()
method. Inversely, it is possible to force the module to forget its current settings by using the
YModule.revertFromFlash()
The short example below allows you to modify the logical name of a module.
method. package com.yoctopuce.doc_examples
; import android.app.Activity
; import android.os.Bundle
; import android.view.View
; import android.widget.AdapterView
; import android.widget.AdapterView.OnItemSelectedListener
; import android.widget.ArrayAdapter
; import android.widget.EditText
; import android.widget.Spinner
; import android.widget.TextView
; import android.widget.Toast
; import com.yoctopuce.YoctoAPI.YAPI
; import com.yoctopuce.YoctoAPI.YAPI_Exception
; import com.yoctopuce.YoctoAPI.YModule
; public class SaveSettings extends Activity implements OnItemSelectedListener
{ private ArrayAdapter<String> aa; private YModule module = null ;
@Override public void onCreate ( Bundle savedInstanceState )
{ super .
onCreate ( savedInstanceState ) ;
setContentView ( R.
layout .
savesettings ) ;
Spinner my_spin = ( Spinner ) findViewById ( R.
id .
spinner1 ) ;
my_spin.
setOnItemSelectedListener (this) ;
aa = new ArrayAdapter<String> (this , android.
R .
layout .
simple_spinner_item ) ;
aa.
setDropDownViewResource ( android.
R .
layout .
simple_spinner_dropdown_item ) ;
my_spin.
setAdapter ( aa ) ;
}
@Override protected void onStart ()
{ super .
onStart () ;
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18. Using the Yocto-Amp with Android
try {
aa.
clear () ;
YAPI.
EnableUSBHost (this) ;
YAPI.
RegisterHub ( "usb" ) ;
YModule r = YModule.
FirstModule () ; while ( r != null ) {
String hwid = r.
get_hardwareId () ;
aa.
add ( hwid ) ;
r = r.
nextModule () ;
}
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
// refresh Spinner with detected relay
aa.
notifyDataSetChanged () ;
}
@Override protected void onStop ()
{ super .
onStop () ;
YAPI.
FreeAPI () ;
} private void DisplayModuleInfo ()
{
TextView field; if ( module == null ) return ; try {
YAPI.
UpdateDeviceList () ;
// fixme
field = ( TextView ) findViewById ( R.
id .
logicalnamefield ) ;
field.
setText ( module.
getLogicalName ()) ;
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
}
@Override public void onItemSelected ( AdapterView<?> parent, View view, int pos, long id )
{
String hwid = parent.
getItemAtPosition ( pos ) .
toString () ;
module = YModule.
FindModule ( hwid ) ;
DisplayModuleInfo () ;
}
@Override public void onNothingSelected ( AdapterView<?> arg0 )
{
} public void saveName ( View view )
{ if ( module == null ) return ;
}
EditText edit = ( EditText ) findViewById ( R.
id .
newname ) ;
String newname = edit.
getText () .
toString () ; try { if ( !YAPI.
CheckLogicalName ( newname )) {
Toast.
makeText ( getApplicationContext () , "Invalid name (" + newname + ")" ,
Toast.
LENGTH_LONG ) .
show () ; return ;
}
module.
set_logicalName ( newname ) ;
module.
saveToFlash () ;
// do not forget this
edit.
setText ( "" ) ;
} catch ( YAPI_Exception ex ) {
ex.
printStackTrace () ;
}
DisplayModuleInfo () ;
}
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18. Using the Yocto-Amp with Android
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to the technology employed by the module micro-processor, is located at about 100000 cycles. In short, you can use the
YModule.saveToFlash()
function only 100000 times in the life of the module.
Make sure you do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the
YModule.yFirstModule() function which returns the first module found. Then, you only need to call the nextModule() function of this object to find the following modules, and this as long as the returned value is not null
. Below a short example listing the connected modules.
package com.yoctopuce.doc_examples
; import android.app.Activity
; import android.os.Bundle
; import android.view.View
; import android.widget.LinearLayout
; import android.widget.TextView
; import com.yoctopuce.YoctoAPI.YAPI
; import com.yoctopuce.YoctoAPI.YAPI_Exception
; import com.yoctopuce.YoctoAPI.YModule
; public class Inventory extends Activity
{
@Override public void onCreate ( Bundle savedInstanceState )
{ super .
onCreate ( savedInstanceState ) ;
setContentView ( R.
layout .
inventory ) ;
} public void refreshInventory ( View view )
{
LinearLayout layout = ( LinearLayout ) findViewById ( R.
id .
inventoryList ) ;
layout.
removeAllViews () ; try {
YAPI.
UpdateDeviceList () ;
YModule module = YModule.
FirstModule () ; while ( module != null ) {
String line = module.
get_serialNumber () + " (" + module.
get_productName () +
")" ;
TextView tx = new TextView (this) ;
tx.
setText ( line ) ;
layout.
addView ( tx ) ;
module = module.
nextModule () ;
}
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
}
@Override protected void onStart ()
{ super .
onStart () ; try {
YAPI.
EnableUSBHost (this) ;
YAPI.
RegisterHub ( "usb" ) ;
} catch ( YAPI_Exception e ) {
e.
printStackTrace () ;
}
refreshInventory ( null ) ;
}
@Override protected void onStop ()
{ super .
onStop () ;
YAPI.
FreeAPI () ;
}
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18. Using the Yocto-Amp with Android
}
18.7. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error handling. Inevitably, there will be a time when a user will have unplugged the device, either before running the software, or even while the software is running. The Yoctopuce library is designed to help you support this kind of behavior, but your code must nevertheless be conceived to interpret in the best possible way the errors indicated by the library.
The simplest way to work around the problem is the one used in the short examples provided in this chapter: before accessing a module, check that it is online with the isOnline
function, and then hope that it will stay so during the fraction of a second necessary for the following code lines to run.
This method is not perfect, but it can be sufficient in some cases. You must however be aware that you cannot completely exclude an error which would occur after the call to isOnline
and which could crash the software.
In the Java API for Android, error handling is implemented with exceptions. Therefore you must catch and handle correctly all exceptions that might be thrown by the API if you do not want your software to crash soon as you unplug a device.
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19. Advanced programming
The preceding chapters have introduced, in each available language, the basic programming functions which can be used with your Yocto-Amp module. This chapter presents in a more generic manner a more advanced use of your module. Examples are provided in the language which is the most popular among Yoctopuce customers, that is C#. Nevertheless, you can find complete examples illustrating the concepts presented here in the programming libraries of each language.
To remain as concise as possible, examples provided in this chapter do not perform any error handling. Do not copy them "as is" in a production application.
19.1. Event programming
The methods to manage Yoctopuce modules which we presented to you in preceding chapters were polling functions, consisting in permanently asking the API if something had changed. While easy to understand, this programming technique is not the most efficient, nor the most reactive. Therefore, the Yoctopuce programming API also provides an event programming model. This technique consists in asking the API to signal by itself the important changes as soon as they are detected.
Each time a key parameter is modified, the API calls a callback function which you have defined in advance.
Detecting module arrival and departure
Hot-plug management is important when you work with USB modules because, sooner or later, you will have to connect or disconnect a module when your application is running. The API is designed to manage module unexpected arrival or departure in a transparent way. But your application must take this into account if it wants to avoid pretending to use a disconnected module.
Event programming is particularly useful to detect module connection/disconnection. Indeed, it is simpler to be told of new connections rather than to have to permanently list the connected modules to deduce which ones just arrived and which ones left. To be warned as soon as a module is connected, you need three pieces of code.
The callback
The callback is the function which is called each time a new Yoctopuce module is connected. It takes as parameter the relevant module.
static void deviceArrival ( YModule m )
{
Console .
WriteLine ( "New module : " + m.
get_serialNumber ()) ;
}
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19. Advanced programming
Initialization
You must then tell the API that it must call the callback when a new module is connected.
YAPI.
RegisterDeviceArrivalCallback ( deviceArrival ) ;
Note that if modules are already connected when the callback is registered, the callback is called for each of the already connected modules.
Triggering callbacks
A classis issue of callback programming is that these callbacks can be triggered at any time, including at times when the main program is not ready to receive them. This can have undesired side effects, such as dead-locks and other race conditions. Therefore, in the Yoctopuce API, module arrival/departure callbacks are called only when the
You only need to call
UpdateDeviceList()
UpdateDeviceList()
function is running.
at regular intervals from a timer or from a specific thread to precisely control when the calls to these callbacks happen:
// waiting loop managing callbacks
while ( true )
{
// module arrival / departure callback
YAPI.
UpdateDeviceList (ref errmsg ) ;
// non active waiting time managing other callbacks
YAPI.
Sleep ( 500 , ref errmsg ) ;
}
In a similar way, it is possible to have a callback when a module is disconnected. You can find a complete example implemented in your favorite programming language in the Examples/Prog-
EventBased directory of the corresponding library.
Be aware that in most programming languages, callbacks must be global procedures, and not methods. If you wish for the callback to call the method of an object, define your callback as a global procedure which then calls your method.
Detecting a modification in the value of a sensor
The Yoctopuce API also provides a callback system allowing you to be notified automatically with the value of any sensor, either when the value has changed in a significant way or periodically at a preset frequency. The code necessary to do so is rather similar to the code used to detect when a new module has been connected.
This technique is useful in particular if you want to detect very quick value changes (within a few milliseconds), as it is much more efficient than reading repeatedly the sensor value and therefore gives better performances.
Calliback invocation
To enable a better control, value change callbacks are only called when the
YAPI.Sleep()
and
YAPI.HandleEvents()
functions are running. Therefore, you must call one of these functions at a regular interval, either from a timer or from a parallel thread.
while ( true )
{
// inactive waiting loop allowing you to trigger
// value change callbacks
YAPI.
Sleep ( 500 , ref errmsg ) ;
}
In programming environments where only the interface thread is allowed to interact with the user, it is often appropriate to call
YAPI.HandleEvents()
from this thread.
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19. Advanced programming
The value change callback
This type of callback is called when a current sensor changes in a significant way. It takes as parameter the relevant function and the new value, as a character string.
1 static void valueChangeCallback ( YCurrent fct, string value )
{
Console .
WriteLine ( fct.
get_hardwareId () + "=" + value ) ;
}
In most programming languages, callbacks are global procedures, not methods. If you wish for the callback to call a method of an object, define your callback as a global procedure which then calls your method. If you need to keep a reference to your object, you can store it directly in the YCurrent object using function set_userData
. You can then retrieve it in the global callback procedure using get_userData
.
Setting up a value change callback
The callback is set up for a given Current function with the help of the registerValueCallback method. The following example sets up a callback for the first available Current function.
YCurrent f = YCurrent.
FirstCurrent () ; f.
registerValueCallback ( current1ChangeCallBack )
Note that each module function can thus have its own distinct callback. By the way, if you like to work with value change callbacks, you will appreciate the fact that value change callbacks are not limited to sensors, but are also available for all Yoctopuce devices (for instance, you can also receive a callback any time a relay state changes).
The timed report callback
This type of callback is automatically called at a predefined time interval. The callback frequency can be configured individually for each sensor, with frequencies going from hundred calls per seconds down to one call per hour. The callback takes as parameter the relevant function and the measured value, as an
YMeasure
object. Contrarily to the value change callback that only receives the latest value, an
YMeasure
object provides both minimal, maximal and average values since the timed report callback. Moreover, the measure includes precise timestamps, which makes it possible to use timed reports for a time-based graph even when not handled immediately.
static void periodicCallback ( YCurrent fct, YMeasure measure )
{
Console .
WriteLine ( fct.
get_hardwareId () + "=" +
measure.
get_averageValue ()) ;
}
Setting up a timed report callback
The callback is set up for a given Current function with the help of the registerTimedReportCallback
method. The callback will only be invoked once a callback frequency as been set using set_reportFrequency
(which defaults to timed report callback turned off). The frequency is specified as a string (same as for the data logger), by specifying the number of calls per second (/s), per minute (/m) or per hour (/h). The maximal frequency is 100 times per second (i.e. "100/s"), and the minimal frequency is 1 time per hour (i.e. "1/h"). When the frequency is higher than or equal to 1/s, the measure represents an instant value. When the frequency is below, the measure will include distinct minimal, maximal and average values based on a sampling performed automatically by the device.
The following example sets up a timed report callback 4 times per minute for t he first available
Current function.
YCurrent f = YCurrent.
FirstCurrent () ; f.
set_reportFrequency ( "4/m" ) ;
1
The value passed as parameter is the same as the value returned by the get_advertisedValue()
method.
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19. Advanced programming
f.
registerTimedReportCallback ( periodicCallback ) ;
As for value change callbacks, each module function can thus have its own distinct timed report callback.
Generic callback functions
It is sometimes desirable to use the same callback function for various types of sensors (e.g. for a generic sensor graphing application). This is possible by defining the callback for an object of class
YSensor
rather than
YCurrent
. Thus, the same callback function will be usable with any subclass of
YSensor
(and in particular with
YCurrent
). With the callback function, you can use the method get_unt()
to get the physical unit of the sensor, if you need to display it.
A complete example
You can find a complete example implemented in your favorite programming language in the
Examples/Prog-EventBased directory of the corresponding library.
19.2. The data logger
Your Yocto-Amp is equipped with a data logger able to store non-stop the measures performed by the module. The maximal frequency is 100 times per second (i.e. "100/s"), and the minimal frequency is 1 time per hour (i.e. "1/h"). When the frequency is higher than or equal to 1/s, the measure represents an instant value. When the frequency is below, the measure will include distinct minimal, maximal and average values based on a sampling performed automatically by the device.
The data logger flash memory can store about 500'000 instant measures, or 125'000 averaged measures. When the memory is about to be saturated, the oldest measures are automatically erased.
Make sure not to leave the data logger running at high speed unless really needed: the flash memory can only stand a limited number of erase cycles (typically 100'000 cycles). When running at full speed, the datalogger can burn more than 100 cycles per day ! Also be aware that it is useless to record measures at a frequency higher than the refresh frequency of the physical sensor itself.
Starting/stopping the datalogger
The data logger can be started with the set_recording()
method.
YDataLogger l = YDataLogger.
FirstDataLogger () ; l.
set_recording ( YDataLogger.
RECORDING_ON ) ;
It is possible to make the data recording start automatically as soon as the module is powered on.
YDataLogger l = YDataLogger.
FirstDataLogger () ; l.
set_autoStart ( YDataLogger.
AUTOSTART_ON ) ; l.
get_module () .
saveToFlash () ;
// do not forget to save the setting
Note: Yoctopuce modules do not need an active USB connection to work: they start working as soon as they are powered on. The Yocto-Amp can store data without necessarily being connected to a computer: you only need to activate the automatic start of the data logger and to power on the module with a simple USB charger.
Erasing the memory
The memory of the data logger can be erased with the forgetAllDataStreams()
function. Be aware that erasing cannot be undone.
YDataLogger l = YDataLogger.
FirstDataLogger () ; l.
forgetAllDataStreams () ;
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Choosing the logging frequency
The logging frequency can be set up individually for each sensor, using the method set_logFrequency()
. The frequency is specified as a string (same as for timed report callbacks), by specifying the number of calls per second (/s), per minute (/m) or per hour (/h). The default value is "1/s".
The following example configures the logging frequency at 15 measures per minute for the first sensor found, whatever its type:
YSensor sensor = YSensor.
FirstSensor () ; sensor.
set_logFrequency ( "15/m" ) ;
To avoid wasting flash memory, it is possible to disable logging for specified functions. In order to do so, simply use the value "OFF": sensor.
set_logFrequency ( "OFF" ) ;
Limitation: The Yocto-Amp cannot use a different frequency for timed-report callbacks and for recording data into the datalogger. You can disable either of them individually, but if you enable both timed-report callbacks and logging for a given function, the two will work at the same frequency.
Retrieving the data
To load recorded measures from the Yocto-Amp flash memory, you must call the get_recordedData()
method of the desired sensor, and specify the time interval for which you want to retrieve measures. The time interval is given by the start and stop UNIX timestamp. You can also specify 0 if you don't want any start or stop limit.
The get_recordedData()
method does not return directly am array of measured values, since in some cases it would cause a huge load that could affect the responsiveness of the application.
Instead, this function will return an
YDataSet
object that can be used to retrieve immediately an overview of the measured data (summary), and then to load progressively the details when desired.
Here are the main methods used to retrieve recorded measures:
1. dataset = sensor.get_recordedData(0,0): select the desired time interval
2. dataset.loadMore(): load data from the device, progressively
3. dataset.get_summary(): get a single measure summarizing the full time interval
4. dataset.get_preview(): get an array of measures representing a condensed version of the whole set of measures on the selected time interval (reduced by a factor of approx. 200)
5. dataset.get_measures(): get an array with all detailled measures (that grows while loadMore
is being called repeteadly)
Measures are instances of
YMeasure
2
. They store simultaneously the minimal, average and maximal value at a given time, that you can retrieve using methods get_minValue(),
get_averageValue() and get_maxValue() respectively. Here is a small example that uses the functions above:
// We will retrieve all measures, without time limit
YDataSet dataset = sensor.
get_recordedData ( 0 , 0 ) ;
// First call to loadMore() loads the summary/preview
dataset.
loadMore () ;
YMeasure summary = dataset.
get_summary () ; string timeFmt = "dd MMM yyyy hh:mm:ss,fff" ; string logFmt = "from {0} to {1} : average={2:0.00}{3}" ;
Console .
WriteLine ( String.
Format ( logFmt,
summary.
get_startTimeUTC_asDateTime () .
ToString ( timeFmt ) ,
summary.
get_endTimeUTC_asDateTime () .
ToString ( timeFmt ) ,
summary.
get_averageValue () , sensor.
get_unit ())) ;
2
The
YMeasure
objects used by the data logger are exactly the same kind as those passed as argument to the timed report callbacks.
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19. Advanced programming
// Next calls to loadMore() will retrieve measures
Console .
WriteLine ( "loading details" ) ; int progress; do {
Console .
Write ( "." ) ;
progress = dataset.
loadMore () ;
} while( progress < 100 ) ;
// All measures have now been loaded
List<YMeasure> details = dataset.
get_measures () ; foreach ( YMeasure m in details ) {
Console .
WriteLine ( String.
Format ( logFmt,
m.
get_startTimeUTC_asDateTime () .
ToString ( timeFmt ) ,
m.
get_endTimeUTC_asDateTime () .
ToString ( timeFmt ) ,
m.
get_averageValue () , sensor.
get_unit ())) ;
}
You will find a complete example demonstrating how to retrieve data from the logger for each programming language directly in the Yoctopuce library. The example can be found in directory
Examples/Prog-DataLogger.
Timestamp
As the Yocto-Amp does not have a battery, it cannot guess alone the current time when powered on.
Nevertheless, the Yocto-Amp will automatically try to adjust its real-time reference using the host to which it is connected, in order to properly attach a timestamp to each measure in the datalogger:
• When the Yocto-Amp is connected to a computer running either the VirtualHub or any application using the Yoctopuce library, it will automatically receive the time from this computer.
• When the Yocto-Amp is connected to a YoctoHub-Ethernet, it will get the time that the
YoctoHub has obtained from the network (using a server from pool.ntp.org
)
• When the Yocto-Amp is connected to a YoctoHub-Wireless, it will get the time provided by the
YoctoHub based on its internal battery-powered real-time clock, which was itself configured either from the network or from a computer
• When the Yocto-Amp is connected to an Android mobile device, it will get the time from the mobile device as long as an app using the Yoctopuce library is launched.
When none of these conditions applies (for instance if the module is simply connected to an USB charger), the Yocto-Amp will do its best effort to attach a reasonable timestamp to the measures, using the timestamp found on the latest recorded measures. It is therefore possible to "preset to the real time" an autonomous Yocto-Amp by connecting it to an Android mobile phone, starting the data logger, then connecting the device alone on an USB charger. Nevertheless, be aware that without external time source, the internal clock of the Yocto-Amp might be be subject to a clock skew
(theoretically up to 0.3%).
19.3. Sensor calibration
Your Yocto-Amp module is equipped with a digital sensor calibrated at the factory. The values it returns are supposed to be reasonably correct in most cases. There are, however, situations where external conditions can impact the measures.
The Yoctopuce API provides the mean to re-caliber the values measured by your Yocto-Amp. You are not going to modify the hardware settings of the module, but rather to transform afterwards the measures taken by the sensor. This transformation is controlled by parameters stored in the flash memory of the module, making it specific for each module. This re-calibration is therefore a fully software matter and remains perfectly reversible.
Before deciding to re-calibrate your Yocto-Amp module, make sure you have well understood the phenomena which impact the measures of your module, and that the differences between true values and measured values do not result from a incorrect use or an inadequate location of the module.
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The Yoctopuce modules support two types of calibration. On the one hand, a linear interpolation based on 1 to 5 reference points, which can be performed directly inside the Yocto-Amp. On the other hand, the API supports an external arbitrary calibration, implemented with callbacks.
1 to 5 point linear interpolation
These transformations are performed directly inside the Yocto-Amp which means that you only have to store the calibration points in the module flash memory, and all the correction computations are done in a perfectly transparent manner: The function get_currentValue()
returns the corrected value while the function get_currentRawValue()
keeps returning the value before the correction.
Calibration points are simply (Raw_value, Corrected_value) couples. Let us look at the impact of the number of calibration points on the corrections.
1 point correction
The 1 point correction only adds a shift to the measures. For example, if you provide the calibration point (a, b), all the measured values are corrected by adding to them b-a, so that when the value read on the sensor is a, the current1 function returns b.
Measure correction with 1 calibration point, here (5,10)
The application is very simple: you only need to call the calibrateFromPoints() method of the function you wish to correct. The following code applies the correction illustrated on the graph above to the first current1 function found. Note the call to the saveToFlash method of the module hosting the function, so that the module does not forget the calibration as soon as it is disconnected.
Double [] ValuesBefore = { 5 } ;
Double [] ValuesAfter = { 10 } ;
YCurrent f = YCurrent.
FirstCurrent () ; f.
calibrateFromPoints ( ValuesBefore, ValuesAfter ) ; f.
get_module () .
saveToFlash () ;
2 point correction
2 point correction allows you to perform both a shift and a multiplication by a given factor between two points. If you provide the two points (a, b) and (c, d), the function result is multiplied (d-b)/(c-a) in the [a, c] range and shifted, so that when the value read by the sensor is a or c, the current1 function returns respectively b and d. Outside of the [a, c] range, the values are simply shifted, so as to preserve the continuity of the measures: an increase of 1 on the value read by the sensor induces an increase of 1 on the returned value.
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Measure correction with the two calibration points (10,5) and (25,10).
The code allowing you to program this calibration is very similar to the preceding code example.
Double [] ValuesBefore = { 10 , 25 } ;
Double [] ValuesAfter = { 5 , 10 } ;
YCurrent f = YCurrent.
FirstCurrent () ; f.
calibrateFromPoints ( ValuesBefore, ValuesAfter ) ; f.
get_module () .
saveToFlash () ;
Note that the values before correction must be sorted in a strictly ascending order, otherwise they are simply ignored.
3 to 5 point correction
3 to 5 point corrections are only a generalization of the 2 point method, allowing you to create up to 4 correction ranges for an increased precision. These ranges cannot be disjoint.
Correction example with 3 calibration points
Back to normal
To cancel the effect of a calibration on a function, call the calibrateFromPoints() method with two empty arrays.
Double [] ValuesBefore = {} ;
Double [] ValuesAfter = {} ;
YCurrent f = YCurrent.
FirstCurrent () ;
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f.
calibrateFromPoints ( ValuesBefore, ValuesAfter ) ; f.
get_module () .
saveToFlash () ;
You will find, in the Examples\Prog-Calibration directory of the Delphi, VB, and C# libraries, an application allowing you to test the effects of the 1 to 5 point calibration.
Arbitrary interpolation
It is also possible to compute the interpolation instead of letting the module do it, in order to calculate a spline interpolation, for instance. To do so, you only need to store a callback in the API. This callback must specify the number of calibration points it is expecting.
public static double CustomInterpolation3Points ( double rawValue, int calibType, int [] parameters, double [] beforeValues, double [] afterValues )
{ double result;
// the value to be corrected is rawValue
// calibration points are in beforeValues and afterValues
result = ....
// interpolation of your choice
return result;
}
YAPI.
RegisterCalibrationHandler ( 3 , CustomInterpolation3Points ) ;
Note that these interpolation callbacks are global, and not specific to each function. Thus, each time someone requests a value from a module which contains in its flash memory the correct number of calibration points, the corresponding callback is called to correct the value before returning it, enabling thus a perfectly transparent measure correction.
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Yoctopuce modules can be driven from most common programming languages. New languages are regularly added, depending on the interest expressed by Yoctopuce product users. Nevertheless, some languages are not, and will never be, supported by Yoctopuce. There can be several reasons for this: compilers which are not available anymore, unadapted environments, etc.
However, there are alternative methods to access Yoctopuce modules from an unsupported programming language.
20.1. Command line
The easiest method to drive Yoctopuce modules from an unsupported programming language is to use the command line API through system calls. The command line API is in fact made of a group of small executables which are easy to call. Their output is also easy to analyze. As most programming languages allow you to make system calls, the issue is solved with a few lines of code.
However, if the command line API is the easiest solution, it is neither the fastest nor the most efficient. For each call, the executable must initialize its own API and make an inventory of USB connected modules. This requires about one second per call.
20.2. VirtualHub and HTTP GET
The VirtualHub is available on almost all current platforms. It is generally used as a gateway to provide access to Yoctopuce modules from languages which prevent direct access to hardware layers of a computer (JavaScript, PHP, Java, ...).
In fact, the VirtualHub is a small web server able to route HTTP requests to Yoctopuce modules. This means that if you can make an HTTP request from your programming language, you can drive
Yoctopuce modules, even if this language is not officially supported.
REST interface
At a low level, the modules are driven through a REST API. Thus, to control a module, you only need to perform appropriate requests on the VirtualHub. By default, the VirtualHub HTTP port is 4444.
An important advantage of this technique is that preliminary tests are very easy to implement. You only need a VirtualHub and a simple web browser. If you copy the following URL in your preferred browser, while the VirtualHub is running, you obtain the list of the connected modules.
http://127.0.0.1:4444/api/services/whitePages.txt
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Note that the result is displayed as text, but if you request whitePages.xml, you obtain an XML result.
Likewise, whitePages.json allows you to obtain a JSON result. The html extension even allows you to display a rough interface where you can modify values in real time. The whole REST API is available in these different formats.
Driving a module through the REST interface
Each Yoctopuce module has its own REST interface, available in several variants. Let us imagine a
Yocto-Amp with the YAMPMK01-12345 serial number and the myModule logical name. The following
URL allows you to know the state of the module.
http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/module.txt
You can naturally also use the module logical name rather than its serial number.
http://127.0.0.1:4444/byName/myModule/api/module.txt
To retrieve the value of a module property, simply add the name of the property below module. For example, if you want to know the signposting led luminosity, send the following request: http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/module/luminosity
To change the value of a property, modify the corresponding attribute. Thus, to modify the luminosity, send the following request: http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/module?luminosity=100
Driving the module functions through the REST interface
The module functions can be manipulated in the same way. To know the state of the current function, build the following URL: http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/current.txt
Note that if you can use logical names for the modules instead of their serial number, you cannot use logical names for functions. Only hardware names are authorized to access functions.
You can retrieve a module function attribute in a way rather similar to that used with the modules. For example: http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/current/logicalName
Rather logically, attributes can be modified in the same manner.
http://127.0.0.1:4444/bySerial/YAMPMK01-12345/api/current?logicalName=myFunction
You can find the list of available attributes for your Yocto-Amp at the beginning of the Programming chapter.
Accessing Yoctopuce data logger through the REST interface
This section only applies to devices with a built-in data logger.
The preview of all recorded data streams can be retrieved in JSON format using the following URL: http://127.0.0.1:4444/bySerial/YAMPMK01-12345/dataLogger.json
Individual measures for any given stream can be obtained by appending the desired function identifier as well as start time of the stream:
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http://127.0.0.1:4444/bySerial/YAMPMK01-12345/dataLogger.json?id=current &utc=1389801080
20.3. Using dynamic libraries
The low level Yoctopuce API is available under several formats of dynamic libraries written in C. The sources are available with the C++ API. If you use one of these low level libraries, you do not need the VirtualHub anymore.
Filename
libyapi.dylib
libyapi-amd64.so
libyapi-armel.so
Platform
Max OS X
Linux Intel (64 bits)
Linux ARM EL libyapi-armhf.so
libyapi-i386.so
yapi64.dll
Linux ARM HL
Linux Intel (32 bits)
Windows (64 bits) yapi.dll
Windows (32 bits)
These dynamic libraries contain all the functions necessary to completely rebuild the whole high level
API in any language able to integrate these libraries. This chapter nevertheless restrains itself to describing basic use of the modules.
Driving a module
The three essential functions of the low level API are the following: int yapiInitAPI ( int connection_type, char *errmsg ) ; int yapiUpdateDeviceList ( int forceupdate, char *errmsg ) ; int yapiHTTPRequest ( char *device, char *request, char * buffer, int buffsize, int *fullsize, char *errmsg ) ;
The yapiInitAPI function initializes the API and must be called once at the beginning of the program.
For a USB type connection, the connection_type parameter takes value 1. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.
The yapiUpdateDeviceList manages the inventory of connected Yoctopuce modules. It must be called at least once. To manage hot plug and detect potential newly connected modules, this function must be called at regular intervals. The forceupdate parameter must take value 1 to force a hardware scan. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.
Finally, the yapiHTTPRequest function sends HTTP requests to the module REST API. The device parameter contains the serial number or the logical name of the module which you want to reach.
The request parameter contains the full HTTP request (including terminal line breaks). buffer points to a character buffer long enough to contain the answer. buffsize is the size of the buffer. fullsize is a pointer to an integer to which will be assigned the actual size of the answer. The errmsg parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.
The format of the requests is the same as the one described in the VirtualHub et HTTP GET section.
All the character strings used by the API are strings made of 8-bit characters: Unicode and UTF8 are not supported.
The resutlt returned in the buffer variable respects the HTTP protocol. It therefore includes an HTTP header. This header ends with two empty lines, that is a sequence of four ASCII characters 13, 10,
13, 10.
Here is a sample program written in pascal using the yapi.dll DLL to read and then update the luminosity of a module.
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// Dll functions import
function yapiInitAPI ( mode: integer ;
errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiInitAPI' ; function yapiUpdateDeviceList ( force: integer ;errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiUpdateDeviceList' ; function yapiHTTPRequest ( device: pansichar ;url: pansichar ; buffer: pansichar ;
buffsize: integer ; var fullsize: integer ;
errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiHTTPRequest' ; var
errmsgBuffer : array [ 0 ..
256 ] of ansichar ;
dataBuffer : array [ 0 ..
1024 ] of ansichar ;
errmsg,data : pansichar ;
fullsize,p : integer ; const
serial = 'YAMPMK01-12345' ;
getValue = 'GET /api/module/luminosity HTTP/1.1'#13#10#13#10 ;
setValue = 'GET /api/module?luminosity=100 HTTP/1.1'#13#10#13#10 ; begin
errmsg := @errmsgBuffer;
data := @dataBuffer;
// API initialization
if( yapiInitAPI ( 1 ,errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ;
// forces a device inventory
if( yapiUpdateDeviceList ( 1 ,errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ;
// requests the module luminosity
if ( yapiHTTPRequest ( serial,getValue,data, sizeof ( dataBuffer ) ,fullsize,errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ;
// searches for the HTTP header end
p := pos ( #13#10#13#10 ,data ) ;
// displays the response minus the HTTP header
writeln ( copy ( data,p+ 4 , length ( data ) -p3 )) ;
// changes the luminosity
if ( yapiHTTPRequest ( serial,setValue,data, sizeof ( dataBuffer ) ,fullsize,errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ; end .
Module inventory
To perform an inventory of Yoctopuce modules, you need two functions from the dynamic library: int yapiGetAllDevices ( int *buffer, int maxsize, int *neededsize, char *errmsg ) ; int yapiGetDeviceInfo ( int devdesc,yDeviceSt *infos, char *errmsg ) ;
The yapiGetAllDevices function retrieves the list of all connected modules as a list of handles. buffer points to a 32-bit integer array which contains the returned handles. maxsize is the size in bytes of the buffer. To neededsize is assigned the necessary size to store all the handles. From this, you can deduce either the number of connected modules or that the input buffer is too small. The errmsg
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parameter must point to a 255 character buffer to retrieve a potential error message. This pointer can also point to null. The function returns a negative integer in case of error, zero otherwise.
The yapiGetDeviceInfo function retrieves the information related to a module from its handle.
devdesc is a 32-bit integer representing the module and which was obtained through
yapiGetAllDevices. infos points to a data structure in which the result is stored. This data structure has the following format:
Name
vendorid deviceid devrelease
Type
int int int
Size
(bytes)
Description
4
4
4
Yoctopuce USB ID
Module USB ID
Module version nbinbterfaces int 4 Number of USB interfaces used by the module manufacturer char[] 20 Yoctopuce (null terminated) productname char[] 28 Model (null terminated) serial char[] 20 Serial number (null terminated) logicalname char[] 20 Logical name (null terminated) firmware char[] 22 Firmware version (null terminated) beacon byte 1 Beacon state (0/1)
The errmsg parameter must point to a 255 character buffer to retrieve a potential error message.
Here is a sample program written in pascal using the yapi.dll DLL to list the connected modules.
// device description structure
type yDeviceSt = packed record
vendorid : word ;
deviceid : word ;
devrelease : word ;
nbinbterfaces : word ;
manufacturer : array [ 0 ..
19 ] of ansichar ;
productname : array [ 0 ..
27 ] of ansichar ;
serial : array [ 0 ..
19 ] of ansichar ;
logicalname : array [ 0 ..
19 ] of ansichar ;
firmware : array [ 0 ..
21 ] of ansichar ;
beacon : byte ; end ;
// Dll function import
function yapiInitAPI ( mode: integer ;
errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiInitAPI' ; function yapiUpdateDeviceList ( force: integer ;errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiUpdateDeviceList' ; function yapiGetAllDevices ( buffer: pointer ;
maxsize: integer ; var neededsize: integer ;
errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiGetAllDevices' ; function apiGetDeviceInfo ( d: integer ; var infos:yDeviceSt;
errmsg : pansichar ) : integer ; cdecl ; external 'yapi.dll' name 'yapiGetDeviceInfo' ; var
errmsgBuffer : array [ 0 ..
256 ] of ansichar ;
dataBuffer : array [ 0 ..
127 ] of integer ;
// max of 128 USB devices
errmsg,data : pansichar ;
neededsize,i : integer ;
devinfos : yDeviceSt; begin
errmsg := @errmsgBuffer;
// API initialization
if( yapiInitAPI ( 1 ,errmsg ) < 0 ) then begin writeln ( errmsg ) ;
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halt ; end ;
// forces a device inventory
if( yapiUpdateDeviceList ( 1 ,errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ;
// loads all device handles into dataBuffer
if yapiGetAllDevices ( @dataBuffer, sizeof ( dataBuffer ) ,neededsize,errmsg ) < 0 then begin writeln ( errmsg ) ; halt ; end ;
// gets device info from each handle
for i:= 0 to neededsize div sizeof ( integer ) 1 do begin if ( apiGetDeviceInfo ( dataBuffer [ i ] , devinfos, errmsg ) < 0 ) then begin writeln ( errmsg ) ; halt ; end ; writeln ( pansichar ( @devinfos.
serial ) + ' (' + pansichar ( @devinfos.
productname ) + ')' ) ; end ; end .
20.4. Porting the high level library
As all the sources of the Yoctopuce API are fully provided, you can very well port the whole API in the language of your choice. Note, however, that a large portion of the API source code is automatically generated.
Therefore, it is not necessary for you to port the complete API. You only need to port the yocto_api file and one file corresponding to a function, for example yocto_relay. After a little additional work,
Yoctopuce is then able to generate all other files. Therefore, we highly recommend that you contact
Yoctopuce support before undertaking to port the Yoctopuce library in another language.
Collaborative work is advantageous to both parties.
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This chapter summarizes the high-level API functions to drive your Yocto-Amp. Syntax and exact type names may vary from one language to another, but, unless otherwise stated, all the functions are available in every language. For detailed information regarding the types of arguments and return values for a given language, refer to the definition file for this language ( yocto_api.*
as well as the other yocto_*
files that define the function interfaces).
For languages which support exceptions, all of these functions throw exceptions in case of error by default, rather than returning the documented error value for each function. This is by design, to facilitate debugging. It is however possible to disable the use of exceptions using the yDisableExceptions()
function, in case you prefer to work with functions that return error values.
This chapter does not repeat the programming concepts described earlier, in order to stay as concise as possible. In case of doubt, do not hesitate to go back to the chapter describing in details all configurable attributes.
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21.1. General functions
These general functions should be used to initialize and configure the Yoctopuce library. In most cases, a simple call to function yRegisterHub()
should be enough. The module-specific functions yFind...()
or yFirst...()
should then be used to retrieve an object that provides interaction with the module.
In order to use the functions described here, you should include: js nodejs php cpp m
<script type='text/javascript' src='yocto_api.js'></script> var yoctolib = require('yoctolib'); var YAPI = yoctolib.YAPI; var YModule = yoctolib.YModule; require_once('yocto_api.php');
#include "yocto_api.h"
#import "yocto_api.h" pas vb cs java py uses yocto_api; yocto_api.vb
yocto_api.cs
import com.yoctopuce.YoctoAPI.YModule; from yocto_api import *
Global functions
name
)
Checks if a given string is valid as logical name for a module or a function.
Disables the use of exceptions to report runtime errors.
Re-enables the use of exceptions for runtime error handling.
osContext
)
This function is used only on Android.
Frees dynamically allocated memory blocks used by the Yoctopuce library.
Returns the version identifier for the Yoctopuce library in use.
Returns the current value of a monotone millisecond-based time counter.
errmsg
)
Maintains the device-to-library communication channel.
mode
,
errmsg
)
Initializes the Yoctopuce programming library explicitly.
url
,
errmsg
)
Fault-tolerant alternative to RegisterHub().
yRegisterDeviceArrivalCallback(
arrivalCallback
)
Register a callback function, to be called each time a device is pluged.
yRegisterDeviceRemovalCallback(
removalCallback
)
Register a callback function, to be called each time a device is unpluged.
url
,
errmsg
)
Setup the Yoctopuce library to use modules connected on a given machine.
yRegisterHubDiscoveryCallback(
callback
)
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Register a callback function, to be called each time a network hub or a VirtualHub is detected on the local network.
logfun
)
Registers a log callback function.
arch
)
Select the architecture or the library to be loaded to access to USB.
object
)
(Objective-C only) Register an object that must follow the procol YDeviceHotPlug .
callback
,
ms_timeout
,
arguments
)
Invoke the specified callback function after a given timeout.
ms_duration
,
errmsg
)
Pauses the execution flow for a specified duration.
url
)
Setup the Yoctopuce library to no more use modules connected on a previously registered machine with
RegisterHub.
errmsg
)
Triggers a (re)detection of connected Yoctopuce modules.
callback
,
context
)
Triggers a (re)detection of connected Yoctopuce modules.
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YAPI.CheckLogicalName() yCheckLogicalName()
YAPI
Checks if a given string is valid as logical name for a module or a function.
js function yCheckLogicalName(
name
) nodejs function CheckLogicalName(
name
) php cpp m pas function yCheckLogicalName(
$name
) bool yCheckLogicalName( const string&
name
)
BOOL yCheckLogicalName( NSString *
name
) function yCheckLogicalName(
name
: string): boolean vb cs java py function yCheckLogicalName( ByVal
name
As String) As Boolean bool CheckLogicalName( string
name
) boolean CheckLogicalName( String
name
) def CheckLogicalName(
name
)
A valid logical name has a maximum of 19 characters, all among
A..Z
, a..z
,
0..9
,
_
, and
-
. If you try to configure a logical name with an incorrect string, the invalid characters are ignored.
Parameters : name
a string containing the name to check.
Returns :
true if the name is valid, false otherwise.
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YAPI.DisableExceptions() yDisableExceptions()
YAPI
Disables the use of exceptions to report runtime errors.
js nodejs function yDisableExceptions( ) function DisableExceptions( ) php cpp function yDisableExceptions( ) void yDisableExceptions( ) m pas vb cs py void yDisableExceptions( ) procedure yDisableExceptions( ) procedure yDisableExceptions( ) void DisableExceptions( ) def DisableExceptions( )
When exceptions are disabled, every function returns a specific error value which depends on its type and which is documented in this reference manual.
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YAPI.EnableExceptions() yEnableExceptions()
YAPI
Re-enables the use of exceptions for runtime error handling.
js function yEnableExceptions( ) nodejs function EnableExceptions( ) php cpp m pas function yEnableExceptions( ) void yEnableExceptions( ) void yEnableExceptions( ) procedure yEnableExceptions( ) vb cs py procedure yEnableExceptions( ) void EnableExceptions( ) def EnableExceptions( )
Be aware than when exceptions are enabled, every function that fails triggers an exception. If the exception is not caught by the user code, it either fires the debugger or aborts (i.e. crash) the program.
On failure, throws an exception or returns a negative error code.
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YAPI.EnableUSBHost() yEnableUSBHost()
YAPI
This function is used only on Android.
java synchronized static void EnableUSBHost( Object
osContext
)
Before calling yRegisterHub("usb")
you need to activate the USB host port of the system. This function takes as argument, an object of class android.content.Context (or any subclasee). It is not necessary to call this function to reach modules through the network.
Parameters : osContext
an object of class android.content.Context (or any subclass).
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YAPI.FreeAPI() yFreeAPI()
YAPI
Frees dynamically allocated memory blocks used by the Yoctopuce library.
js function yFreeAPI( ) nodejs function FreeAPI( ) php cpp m pas function yFreeAPI( ) void yFreeAPI( ) void yFreeAPI( ) procedure yFreeAPI( ) vb cs java py procedure yFreeAPI( ) void FreeAPI( ) synchronized static void FreeAPI( ) def FreeAPI( )
It is generally not required to call this function, unless you want to free all dynamically allocated memory blocks in order to track a memory leak for instance. You should not call any other library function after calling yFreeAPI()
, or your program will crash.
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YAPI.GetAPIVersion() yGetAPIVersion()
YAPI
Returns the version identifier for the Yoctopuce library in use.
js nodejs function yGetAPIVersion( ) function GetAPIVersion( ) php cpp function yGetAPIVersion( ) string yGetAPIVersion( ) m pas vb cs java py
NSString* yGetAPIVersion( ) function yGetAPIVersion( ): string function yGetAPIVersion( ) As String
String GetAPIVersion( )
String GetAPIVersion( ) def GetAPIVersion( )
The version is a string in the form
"Major.Minor.Build"
, for instance
"1.01.5535"
. For languages using an external DLL (for instance C#, VisualBasic or Delphi), the character string includes as well the DLL version, for instance
"1.01.5535 (1.01.5439)"
.
If you want to verify in your code that the library version is compatible with the version that you have used during development, verify that the major number is strictly equal and that the minor number is greater or equal. The build number is not relevant with respect to the library compatibility.
Returns :
a character string describing the library version.
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YAPI.GetTickCount() yGetTickCount()
YAPI
Returns the current value of a monotone millisecond-based time counter.
js function yGetTickCount( ) nodejs function GetTickCount( ) php cpp m pas function yGetTickCount( ) u64 yGetTickCount( ) u64 yGetTickCount( ) function yGetTickCount( ): u64 vb cs java py function yGetTickCount( ) As Long ulong GetTickCount( ) long GetTickCount( ) def GetTickCount( )
This counter can be used to compute delays in relation with Yoctopuce devices, which also uses the millisecond as timebase.
Returns :
a long integer corresponding to the millisecond counter.
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YAPI.HandleEvents() yHandleEvents()
YAPI
Maintains the device-to-library communication channel.
js nodejs function yHandleEvents(
errmsg
) function HandleEvents(
errmsg
) php cpp function yHandleEvents(
&$errmsg
)
YRETCODE yHandleEvents( string&
errmsg
) m pas vb cs java py
YRETCODE yHandleEvents( NSError**
errmsg
) function yHandleEvents( var
errmsg
: string): integer function yHandleEvents( ByRef
errmsg
As String) As YRETCODE
YRETCODE HandleEvents( ref string
errmsg
) int HandleEvents( ) def HandleEvents(
errmsg
=None)
If your program includes significant loops, you may want to include a call to this function to make sure that the library takes care of the information pushed by the modules on the communication channels.
This is not strictly necessary, but it may improve the reactivity of the library for the following commands.
This function may signal an error in case there is a communication problem while contacting a module.
Parameters : errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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YAPI.InitAPI() yInitAPI()
YAPI
Initializes the Yoctopuce programming library explicitly.
js function yInitAPI(
mode
,
errmsg
) nodejs function InitAPI(
mode
,
errmsg
) php cpp m pas function yInitAPI(
$mode
,
&$errmsg
)
YRETCODE yInitAPI( int
mode
, string&
errmsg
)
YRETCODE yInitAPI( int
mode
, NSError**
errmsg
) function yInitAPI(
mode
: integer, var
errmsg
: string): integer vb cs java py function yInitAPI( ByVal
mode
As Integer, ByRef
errmsg
As String) As Integer int InitAPI( int
mode
, ref string
errmsg
) synchronized static int InitAPI( int
mode
) def InitAPI(
mode
,
errmsg
=None)
It is not strictly needed to call yInitAPI()
, as the library is automatically initialized when calling yRegisterHub()
for the first time.
When
Y_DETECT_NONE
is used as detection mode
, you must explicitly use yRegisterHub()
to point the API to the VirtualHub on which your devices are connected before trying to access them.
Parameters : mode
an integer corresponding to the type of automatic device detection to use. Possible values are
Y_DETECT_NONE , Y_DETECT_USB , Y_DETECT_NET , and Y_DETECT_ALL .
errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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YAPI.PreregisterHub() yPreregisterHub()
YAPI
Fault-tolerant alternative to RegisterHub().
js nodejs function yPreregisterHub(
url
,
errmsg
) function PreregisterHub(
url
,
errmsg
) php cpp function yPreregisterHub(
$url
,
&$errmsg
)
YRETCODE yPreregisterHub( const string&
url
, string&
errmsg
) m pas vb
YRETCODE yPreregisterHub( NSString *
url
, NSError**
errmsg
) function yPreregisterHub(
url
: string, var
errmsg
: string): integer function yPreregisterHub( ByVal
url
As String,
ByRef
errmsg
As String) As Integer cs java py int PreregisterHub( string
url
, ref string
errmsg
) synchronized static int PreregisterHub( String
url
) def PreregisterHub(
url
,
errmsg
=None)
This function has the same purpose and same arguments as RegisterHub() , but does not trigger an error when the selected hub is not available at the time of the function call. This makes it possible to register a network hub independently of the current connectivity, and to try to contact it only when a device is actively needed.
Parameters : url
a string containing either "usb","callback" or the root URL of the hub to monitor
errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS when the call succeeds.
On failure, throws an exception or returns a negative error code.
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YAPI.RegisterDeviceArrivalCallback() yRegisterDeviceArrivalCallback()
YAPI
Register a callback function, to be called each time a device is pluged.
js function yRegisterDeviceArrivalCallback(
arrivalCallback
) nodejs function RegisterDeviceArrivalCallback(
arrivalCallback
) php cpp m pas function yRegisterDeviceArrivalCallback(
$arrivalCallback
) void yRegisterDeviceArrivalCallback( yDeviceUpdateCallback
arrivalCallback
) void yRegisterDeviceArrivalCallback( yDeviceUpdateCallback
arrivalCallback
) procedure yRegisterDeviceArrivalCallback(
arrivalCallback
: yDeviceUpdateFunc) vb cs java py procedure yRegisterDeviceArrivalCallback( ByVal
arrivalCallback
As yDeviceUpdateFunc) void RegisterDeviceArrivalCallback( yDeviceUpdateFunc
arrivalCallback
) synchronized static void RegisterDeviceArrivalCallback( DeviceArrivalCallback
arrivalCallback
) def RegisterDeviceArrivalCallback(
arrivalCallback
)
This callback will be invoked while yUpdateDeviceList
is running. You will have to call this function on a regular basis.
Parameters : arrivalCallback
a procedure taking a
YModule
parameter, or null
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YAPI.RegisterDeviceRemovalCallback() yRegisterDeviceRemovalCallback()
YAPI
Register a callback function, to be called each time a device is unpluged.
js nodejs function yRegisterDeviceRemovalCallback(
removalCallback
) function RegisterDeviceRemovalCallback(
removalCallback
) php cpp function yRegisterDeviceRemovalCallback(
$removalCallback
) void yRegisterDeviceRemovalCallback( yDeviceUpdateCallback
removalCallback
) m pas vb cs java py void yRegisterDeviceRemovalCallback( yDeviceUpdateCallback
removalCallback
) procedure yRegisterDeviceRemovalCallback(
removalCallback
: yDeviceUpdateFunc) procedure yRegisterDeviceRemovalCallback( ByVal
removalCallback
As yDeviceUpdateFunc) void RegisterDeviceRemovalCallback( yDeviceUpdateFunc
removalCallback
) synchronized static void RegisterDeviceRemovalCallback( DeviceRemovalCallback
removalCallback
) def RegisterDeviceRemovalCallback(
removalCallback
)
This callback will be invoked while yUpdateDeviceList
is running. You will have to call this function on a regular basis.
Parameters : removalCallback
a procedure taking a
YModule
parameter, or null
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YAPI.RegisterHub() yRegisterHub()
Setup the Yoctopuce library to use modules connected on a given machine.
js function yRegisterHub(
url
,
errmsg
) nodejs function RegisterHub(
url
,
errmsg
) php cpp m pas vb function yRegisterHub(
$url
,
&$errmsg
)
YRETCODE yRegisterHub( const string&
url
, string&
errmsg
)
YRETCODE yRegisterHub( NSString *
url
, NSError**
errmsg
) function yRegisterHub(
url
: string, var
errmsg
: string): integer function yRegisterHub( ByVal
url
As String,
ByRef
errmsg
As String) As Integer cs java py int RegisterHub( string
url
, ref string
errmsg
) synchronized static int RegisterHub( String
url
) def RegisterHub(
url
,
errmsg
=None)
The parameter will determine how the API will work. Use the follwing values:
YAPI
usb: When the usb keyword is used, the API will work with devices connected directly to the USB bus.
Some programming languages such a Javascript, PHP, and Java don't provide direct access to USB harware, so usb will not work with these. In this case, use a VirtualHub or a networked YoctoHub (see below).
x.x.x.x or hostname: The API will use the devices connected to the host with the given IP address or hostname. That host can be a regular computer running a VirtualHub, or a networked YoctoHub such as YoctoHub-Ethernet or YoctoHub-Wireless. If you want to use the VirtualHub running on you local computer, use the IP address 127.0.0.1.
callback: that keywork make the API run in "HTTP Callback" mode. This a special mode allowing to take control of Yoctopuce devices through a NAT filter when using a VirtualHub ou a networked
YoctoHub. You only need to configure your hub to call your server script on a regular basis. This mode is currently available for PHP and Node.JS only.
Be aware that only one application can use direct USB access at a given time on a machine. Multiple access would cause conflicts while trying to access the USB modules. In particular, this means that you must stop the VirtualHub software before starting an application that uses direct USB access. The workaround for this limitation is to setup the library to use the VirtualHub rather than direct USB access.
If acces control has been activated on the hub, virtual or not, you want to reach, the URL parameter should look like: http://username:password@adresse:port
You can call RegisterHub several times to connect to several machines.
Parameters : url
a string containing either "usb","callback" or the root URL of the hub to monitor
errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS when the call succeeds.
On failure, throws an exception or returns a negative error code.
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YAPI.RegisterHubDiscoveryCallback() yRegisterHubDiscoveryCallback()
YAPI
Register a callback function, to be called each time a network hub or a VirtualHub is detected on the local network.
java void RegisterHubDiscoveryCallback( NewHubCallback
callback
)
Parameters : callback
a procedure taking a two string as parameter, or null
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YAPI.RegisterLogFunction() yRegisterLogFunction()
YAPI
Registers a log callback function.
cpp m pas vb cs java py void yRegisterLogFunction( yLogFunction
logfun
) void yRegisterLogFunction( yLogCallback
logfun
) procedure yRegisterLogFunction(
logfun
: yLogFunc) procedure yRegisterLogFunction( ByVal
logfun
As yLogFunc) void RegisterLogFunction( yLogFunc
logfun
) void RegisterLogFunction( LogCallback
logfun
) def RegisterLogFunction(
logfun
)
This callback will be called each time the API have something to say. Quite usefull to debug the API.
Parameters : logfun
a procedure taking a string parameter, or null
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YAPI.SelectArchitecture() ySelectArchitecture()
YAPI
Select the architecture or the library to be loaded to access to USB.
py def SelectArchitecture(
arch
)
By default, the Python library automatically detects the appropriate library to use. However, for Linux
ARM, it not possible to reliably distinguish between a Hard Float (armhf) and a Soft Float (armel) install.
For in this case, it is therefore recommended to manually select the proper architecture by calling
SelectArchitecture() before any other call to the library.
Parameters : arch
A string containing the architecture to use. Possibles value are: "armhf" , "armel" ,
"i386" , "x86_64" , "32bit" , "64bit"
Returns :
nothing.
On failure, throws an exception.
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YAPI.SetDelegate() ySetDelegate()
YAPI
(Objective-C only) Register an object that must follow the procol
YDeviceHotPlug
.
m void ySetDelegate( id
object
)
The methodes y D e v i c e A r r i v a l
and y D e v i c e R e m o v a l
will be invoked while yUpdateDeviceList is running. You will have to call this function on a regular basis.
Parameters : object
an object that must follow the procol YAPIDelegate , or nil
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YAPI.SetTimeout() ySetTimeout()
YAPI
Invoke the specified callback function after a given timeout.
js nodejs function ySetTimeout(
callback
,
ms_timeout
,
arguments
) function SetTimeout(
callback
,
ms_timeout
,
arguments
)
This function behaves more or less like Javascript setTimeout
, but during the waiting time, it will call yHandleEvents and yUpdateDeviceList periodically, in order to keep the API up-to-date with current devices.
Parameters : callback
the function to call after the timeout occurs. On Microsoft Internet Explorer, the callback must be provided as a string to be evaluated.
ms_timeout
an integer corresponding to the duration of the timeout, in milliseconds.
arguments
additional arguments to be passed to the callback function can be provided, if needed (not supported on Microsoft Internet Explorer).
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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YAPI.Sleep() ySleep()
YAPI
Pauses the execution flow for a specified duration.
js function ySleep(
ms_duration
,
errmsg
) nodejs function Sleep(
ms_duration
,
errmsg
) php cpp m pas vb function ySleep(
$ms_duration
,
&$errmsg
)
YRETCODE ySleep( unsigned
ms_duration
, string&
errmsg
)
YRETCODE ySleep( unsigned
ms_duration
, NSError **
errmsg
) function ySleep(
ms_duration
: integer, var
errmsg
: string): integer function ySleep( ByVal
ms_duration
As Integer,
ByRef
errmsg
As String) As Integer cs java py int Sleep( int
ms_duration
, ref string
errmsg
) int Sleep( long
ms_duration
) def Sleep(
ms_duration
,
errmsg
=None)
This function implements a passive waiting loop, meaning that it does not consume CPU cycles significatively. The processor is left available for other threads and processes. During the pause, the library nevertheless reads from time to time information from the Yoctopuce modules by calling yHandleEvents()
, in order to stay up-to-date.
This function may signal an error in case there is a communication problem while contacting a module.
Parameters : ms_duration
an integer corresponding to the duration of the pause, in milliseconds.
errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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YAPI.UnregisterHub() yUnregisterHub()
YAPI
Setup the Yoctopuce library to no more use modules connected on a previously registered machine with RegisterHub.
js nodejs function yUnregisterHub(
url
) function UnregisterHub(
url
) php cpp function yUnregisterHub(
$url
) void yUnregisterHub( const string&
url
) m pas vb cs java py void yUnregisterHub( NSString *
url
) procedure yUnregisterHub(
url
: string) procedure yUnregisterHub( ByVal
url
As String) void UnregisterHub( string
url
) synchronized static void UnregisterHub( String
url
) def UnregisterHub(
url
)
Parameters : url
a string containing either "usb" or the
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YAPI.UpdateDeviceList() yUpdateDeviceList()
YAPI
Triggers a (re)detection of connected Yoctopuce modules.
js function yUpdateDeviceList(
errmsg
) nodejs function UpdateDeviceList(
errmsg
) php cpp m pas function yUpdateDeviceList(
&$errmsg
)
YRETCODE yUpdateDeviceList( string&
errmsg
)
YRETCODE yUpdateDeviceList( NSError**
errmsg
) function yUpdateDeviceList( var
errmsg
: string): integer vb cs java py function yUpdateDeviceList( ByRef
errmsg
As String) As YRETCODE
YRETCODE UpdateDeviceList( ref string
errmsg
) int UpdateDeviceList( ) def UpdateDeviceList(
errmsg
=None)
The library searches the machines or USB ports previously registered using yRegisterHub()
, and invokes any user-defined callback function in case a change in the list of connected devices is detected.
This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.
Parameters : errmsg
a string passed by reference to receive any error message.
Returns :
YAPI_SUCCESS
when the call succeeds. On failure, throws an exception or returns a negative error code.
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YAPI.UpdateDeviceList_async() yUpdateDeviceList_async()
YAPI
Triggers a (re)detection of connected Yoctopuce modules.
js nodejs function yUpdateDeviceList_async(
callback
,
context
) function UpdateDeviceList_async(
callback
,
context
)
The library searches the machines or USB ports previously registered using yRegisterHub()
, and invokes any user-defined callback function in case a change in the list of connected devices is detected.
This function can be called as frequently as desired to refresh the device list and to make the application aware of hot-plug events.
This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the result code (
YAPI_SUCCESS
if the operation completes successfully) and the error message.
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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21.2. Module control interface
This interface is identical for all Yoctopuce USB modules. It can be used to control the module global parameters, and to enumerate the functions provided by each module.
In order to use the functions described here, you should include: js nodejs php cpp
<script type='text/javascript' src='yocto_api.js'></script> var yoctolib = require('yoctolib'); var YAPI = yoctolib.YAPI; var YModule = yoctolib.YModule; require_once('yocto_api.php');
#include "yocto_api.h" m pas vb cs java py
#import "yocto_api.h" uses yocto_api; yocto_api.vb
yocto_api.cs
import com.yoctopuce.YoctoAPI.YModule; from yocto_api import *
Global functions
func
)
Allows you to find a module from its serial number or from its logical name.
Starts the enumeration of modules currently accessible.
YModule
methods
Returns a descriptive text that identifies the module.
pathname
)
Downloads the specified built-in file and returns a binary buffer with its content.
Returns the number of functions (beside the "module" interface) available on the module.
functionIndex
)
Retrieves the hardware identifier of the nth function on the module.
functionIndex
)
Retrieves the logical name of the nth function on the module.
functionIndex
)
Retrieves the advertised value of the nth function on the module.
Returns the state of the localization beacon.
Returns the error message of the latest error with this module object.
Returns the numerical error code of the latest error with this module object.
Returns the version of the firmware embedded in the module.
Returns the unique hardware identifier of the module.
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Returns the icon of the module.
Returns a string with last logs of the module.
Returns the logical name of the module.
Returns the luminosity of the module informative leds (from 0 to 100).
Returns the current state of persistent module settings.
Returns the USB device identifier of the module.
Returns the commercial name of the module, as set by the factory.
Returns the hardware release version of the module.
Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.
Returns the serial number of the module, as set by the factory.
Returns the number of milliseconds spent since the module was powered on.
Returns the number of USB interfaces used by the module.
Returns the current consumed by the module on the USB bus, in milli-amps.
Returns the value of the userData attribute, as previously stored using method set_userData
.
Checks if the module is currently reachable, without raising any error.
callback
,
context
)
Checks if the module is currently reachable, without raising any error.
msValidity
)
Preloads the module cache with a specified validity duration.
msValidity
,
callback
,
context
)
Preloads the module cache with a specified validity duration (asynchronous version).
Continues the module enumeration started using yFirstModule() .
secBeforeReboot
)
Schedules a simple module reboot after the given number of seconds.
Reloads the settings stored in the nonvolatile memory, as when the module is powered on.
Saves current settings in the nonvolatile memory of the module.
newval
)
Turns on or off the module localization beacon.
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newval
)
Changes the logical name of the module.
newval
)
Changes the luminosity of the module informative leds.
newval
)
Changes the number of USB interfaces used by the module.
data
)
Stores a user context provided as argument in the userData attribute of the function.
secBeforeReboot
)
Schedules a module reboot into special firmware update mode.
callback
,
context
)
Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.
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YModule.FindModule() yFindModule()
YModule
Allows you to find a module from its serial number or from its logical name.
js nodejs function yFindModule(
func
) function FindModule(
func
) php cpp function yFindModule(
$func
)
YModule* yFindModule( string
func
) m pas vb cs java py
+(YModule*) yFindModule : (NSString*)
func
function yFindModule(
func
: string): TYModule function yFindModule( ByVal
func
As String) As YModule
YModule FindModule( string
func
)
YModule FindModule( String
func
) def FindModule(
func
)
This function does not require that the module is online at the time it is invoked. The returned object is nevertheless valid. Use the method
YModule.isOnline()
to test if the module is indeed online at a given time. In case of ambiguity when looking for a module by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.
Parameters : func
a string containing either the serial number or the logical name of the desired module
Returns :
a
YModule
object allowing you to drive the module or get additional information on the module.
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YModule.FirstModule() yFirstModule()
Starts the enumeration of modules currently accessible.
js function yFirstModule( ) nodejs function FirstModule( ) php cpp m pas function yFirstModule( )
YModule* yFirstModule( )
YModule* yFirstModule( ) function yFirstModule( ): TYModule vb cs java py function yFirstModule( ) As YModule
YModule FirstModule( )
YModule FirstModule( ) def FirstModule( )
Use the method
YModule.nextModule()
to iterate on the next modules.
YModule
Returns :
a pointer to a YModule object, corresponding to the first module currently online, or a null pointer if there are none.
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module
→
describe()
Returns a descriptive text that identifies the module.
js function describe( ) nodejs function describe( ) php function describe( ) cpp m pas vb cs java py string describe( )
-(NSString*) describe function describe( ): string function describe( ) As String string describe( )
String describe( ) def describe( )
The text may include either the logical name or the serial number of the module.
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YModule
Returns :
a string that describes the module
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module
→
download()
Downloads the specified built-in file and returns a binary buffer with its content.
js function download(
pathname
) nodejs function download(
pathname
) php function download(
$pathname
) cpp m pas vb py cmd string download( string
pathname
)
-(NSData*) download : (NSString*)
pathname
function download(
pathname
: string): TByteArray function download( ) As Byte def download(
pathname
)
YModule
target
download
pathname
Parameters : pathname
name of the new file to load
Returns :
a binary buffer with the file content
On failure, throws an exception or returns an empty content.
YModule
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module
→
functionCount()
Returns the number of functions (beside the "module" interface) available on the module.
js function functionCount( ) nodejs function functionCount( ) php function functionCount( ) cpp m pas vb cs py int functionCount( )
-(int) functionCount function functionCount( ): integer function functionCount( ) As Integer int functionCount( ) def functionCount( )
YModule
Returns :
the number of functions on the module
On failure, throws an exception or returns a negative error code.
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module
→
functionId()
Retrieves the hardware identifier of the nth function on the module.
js function functionId(
functionIndex
) nodejs function functionId(
functionIndex
) php function functionId(
$functionIndex
) cpp m pas vb cs py string functionId( int
functionIndex
)
-(NSString*) functionId : (int)
functionIndex
function functionId(
functionIndex
: integer): string function functionId( ByVal
functionIndex
As Integer) As String string functionId( int
functionIndex
) def functionId(
functionIndex
)
YModule
Parameters : functionIndex
the index of the function for which the information is desired, starting at 0 for the first function.
Returns :
a string corresponding to the unambiguous hardware identifier of the requested module function
On failure, throws an exception or returns an empty string.
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module
→
functionName()
Retrieves the logical name of the nth function on the module.
js function functionName(
functionIndex
) nodejs function functionName(
functionIndex
) php function functionName(
$functionIndex
) cpp m pas vb cs py string functionName( int
functionIndex
)
-(NSString*) functionName : (int)
functionIndex
function functionName(
functionIndex
: integer): string function functionName( ByVal
functionIndex
As Integer) As String string functionName( int
functionIndex
) def functionName(
functionIndex
)
21. High-level API Reference
YModule
Parameters : functionIndex
the index of the function for which the information is desired, starting at 0 for the first function.
Returns :
a string corresponding to the logical name of the requested module function
On failure, throws an exception or returns an empty string.
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module
→
functionValue()
Retrieves the advertised value of the nth function on the module.
js function functionValue(
functionIndex
) nodejs function functionValue(
functionIndex
) php function functionValue(
$functionIndex
) cpp m pas vb cs py string functionValue( int
functionIndex
)
-(NSString*) functionValue : (int)
functionIndex
function functionValue(
functionIndex
: integer): string function functionValue( ByVal
functionIndex
As Integer) As String string functionValue( int
functionIndex
) def functionValue(
functionIndex
)
YModule
Parameters : functionIndex
the index of the function for which the information is desired, starting at 0 for the first function.
Returns :
a short string (up to 6 characters) corresponding to the advertised value of the requested module function
On failure, throws an exception or returns an empty string.
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module
→
get_beacon() module
→
beacon()
Returns the state of the localization beacon.
js nodejs function get_beacon( ) function get_beacon( ) php cpp function get_beacon( )
Y_BEACON_enum get_beacon( ) m pas vb cs
-(Y_BEACON_enum) beacon function get_beacon( ): Integer function get_beacon( ) As Integer int get_beacon( ) java py cmd int get_beacon( ) def get_beacon( )
YModule
target
get_beacon
Returns :
either Y_BEACON_OFF or Y_BEACON_ON , according to the state of the localization beacon
On failure, throws an exception or returns
Y_BEACON_INVALID
.
YModule
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module
→
get_errorMessage() module
→
errorMessage()
Returns the error message of the latest error with this module object.
js function get_errorMessage( ) nodejs function get_errorMessage( ) php cpp m pas function get_errorMessage( ) string get_errorMessage( )
-(NSString*) errorMessage function get_errorMessage( ): string vb cs java py function get_errorMessage( ) As String string get_errorMessage( )
String get_errorMessage( ) def get_errorMessage( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
YModule
Returns :
a string corresponding to the latest error message that occured while using this module object
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module
→
get_errorType() module
→
errorType()
Returns the numerical error code of the latest error with this module object.
js nodejs function get_errorType( ) function get_errorType( ) php cpp function get_errorType( )
YRETCODE get_errorType( ) pas vb cs java py function get_errorType( ): YRETCODE function get_errorType( ) As YRETCODE
YRETCODE get_errorType( ) int get_errorType( ) def get_errorType( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
YModule
Returns :
a number corresponding to the code of the latest error that occured while using this module object
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module
→
get_firmwareRelease() module
→
firmwareRelease()
Returns the version of the firmware embedded in the module.
js function get_firmwareRelease( ) nodejs function get_firmwareRelease( ) php cpp m pas function get_firmwareRelease( ) string get_firmwareRelease( )
-(NSString*) firmwareRelease function get_firmwareRelease( ): string vb cs java py cmd function get_firmwareRelease( ) As String string get_firmwareRelease( )
String get_firmwareRelease( ) def get_firmwareRelease( )
YModule
target
get_firmwareRelease
Returns :
a string corresponding to the version of the firmware embedded in the module
On failure, throws an exception or returns Y_FIRMWARERELEASE_INVALID .
YModule
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module
→
get_hardwareId() module
→
hardwareId()
YModule
Returns the unique hardware identifier of the module.
js nodejs function get_hardwareId( ) function get_hardwareId( ) php cpp function get_hardwareId( ) string get_hardwareId( ) m vb cs java py
-(NSString*) hardwareId function get_hardwareId( ) As String string get_hardwareId( )
String get_hardwareId( ) def get_hardwareId( )
The unique hardware identifier is made of the device serial number followed by string ".module".
Returns :
a string that uniquely identifies the module
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module
→
get_icon2d() module
→
icon2d()
Returns the icon of the module.
js function get_icon2d( ) nodejs function get_icon2d( ) php cpp m pas function get_icon2d( ) string get_icon2d( )
-(NSData*) icon2d function get_icon2d( ): TByteArray vb py cmd function get_icon2d( ) As Byte def get_icon2d( )
YModule
target
get_icon2d
The icon is a PNG image and does not exceeds 1536 bytes.
Returns :
a binary buffer with module icon, in png format.
YModule
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module
→
get_lastLogs() module
→
lastLogs()
Returns a string with last logs of the module.
js nodejs function get_lastLogs( ) function get_lastLogs( ) php cpp function get_lastLogs( ) string get_lastLogs( ) m pas vb cs
-(NSString*) lastLogs function get_lastLogs( ): string function get_lastLogs( ) As String string get_lastLogs( ) java py cmd
String get_lastLogs( ) def get_lastLogs( )
YModule
target
get_lastLogs
This method return only logs that are still in the module.
Returns :
a string with last logs of the module.
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YModule
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module
→
get_logicalName() module
→
logicalName()
Returns the logical name of the module.
js function get_logicalName( ) nodejs function get_logicalName( ) php cpp m pas function get_logicalName( ) string get_logicalName( )
-(NSString*) logicalName function get_logicalName( ): string vb cs java py cmd function get_logicalName( ) As String string get_logicalName( )
String get_logicalName( ) def get_logicalName( )
YModule
target
get_logicalName
Returns :
a string corresponding to the logical name of the module
On failure, throws an exception or returns Y_LOGICALNAME_INVALID .
YModule
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module
→
get_luminosity() module
→
luminosity()
Returns the luminosity of the module informative leds (from 0 to 100).
js nodejs function get_luminosity( ) function get_luminosity( ) php cpp function get_luminosity( ) int get_luminosity( ) m pas vb cs
-(int) luminosity function get_luminosity( ): LongInt function get_luminosity( ) As Integer int get_luminosity( ) java py cmd int get_luminosity( ) def get_luminosity( )
YModule
target
get_luminosity
Returns :
an integer corresponding to the luminosity of the module informative leds (from 0 to 100)
On failure, throws an exception or returns Y_LUMINOSITY_INVALID .
YModule
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module
→
get_persistentSettings() module
→
persistentSettings()
Returns the current state of persistent module settings.
js function get_persistentSettings( ) nodejs function get_persistentSettings( ) php cpp m pas function get_persistentSettings( )
Y_PERSISTENTSETTINGS_enum get_persistentSettings( )
-(Y_PERSISTENTSETTINGS_enum) persistentSettings function get_persistentSettings( ): Integer vb cs java py cmd function get_persistentSettings( ) As Integer int get_persistentSettings( ) int get_persistentSettings( ) def get_persistentSettings( )
YModule
target
get_persistentSettings
YModule
Returns :
a value among Y_PERSISTENTSETTINGS_LOADED , Y_PERSISTENTSETTINGS_SAVED and
Y_PERSISTENTSETTINGS_MODIFIED corresponding to the current state of persistent module settings
On failure, throws an exception or returns Y_PERSISTENTSETTINGS_INVALID .
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module
→
get_productId() module
→
productId()
Returns the USB device identifier of the module.
js nodejs function get_productId( ) function get_productId( ) php cpp function get_productId( ) int get_productId( ) m pas vb cs
-(int) productId function get_productId( ): LongInt function get_productId( ) As Integer int get_productId( ) java py cmd int get_productId( ) def get_productId( )
YModule
target
get_productId
Returns :
an integer corresponding to the USB device identifier of the module
On failure, throws an exception or returns Y_PRODUCTID_INVALID .
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YModule
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module
→
get_productName() module
→
productName()
Returns the commercial name of the module, as set by the factory.
js function get_productName( ) nodejs function get_productName( ) php cpp m pas function get_productName( ) string get_productName( )
-(NSString*) productName function get_productName( ): string vb cs java py cmd function get_productName( ) As String string get_productName( )
String get_productName( ) def get_productName( )
YModule
target
get_productName
Returns :
a string corresponding to the commercial name of the module, as set by the factory
On failure, throws an exception or returns Y_PRODUCTNAME_INVALID .
YModule
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module
→
get_productRelease() module
→
productRelease()
Returns the hardware release version of the module.
js nodejs function get_productRelease( ) function get_productRelease( ) php cpp function get_productRelease( ) int get_productRelease( ) m pas vb cs
-(int) productRelease function get_productRelease( ): LongInt function get_productRelease( ) As Integer int get_productRelease( ) java py cmd int get_productRelease( ) def get_productRelease( )
YModule
target
get_productRelease
Returns :
an integer corresponding to the hardware release version of the module
On failure, throws an exception or returns Y_PRODUCTRELEASE_INVALID .
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YModule
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module
→
get_rebootCountdown() module
→
rebootCountdown()
YModule
Returns the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled.
js function get_rebootCountdown( ) nodejs function get_rebootCountdown( ) php cpp m pas function get_rebootCountdown( ) int get_rebootCountdown( )
-(int) rebootCountdown function get_rebootCountdown( ): LongInt vb cs java py cmd function get_rebootCountdown( ) As Integer int get_rebootCountdown( ) int get_rebootCountdown( ) def get_rebootCountdown( )
YModule
target
get_rebootCountdown
Returns :
an integer corresponding to the remaining number of seconds before the module restarts, or zero when no reboot has been scheduled
On failure, throws an exception or returns
Y_REBOOTCOUNTDOWN_INVALID
.
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module
→
get_serialNumber() module
→
serialNumber()
Returns the serial number of the module, as set by the factory.
js nodejs function get_serialNumber( ) function get_serialNumber( ) php cpp function get_serialNumber( ) string get_serialNumber( ) m pas vb cs
-(NSString*) serialNumber function get_serialNumber( ): string function get_serialNumber( ) As String string get_serialNumber( ) java py cmd
String get_serialNumber( ) def get_serialNumber( )
YModule
target
get_serialNumber
Returns :
a string corresponding to the serial number of the module, as set by the factory
On failure, throws an exception or returns Y_SERIALNUMBER_INVALID .
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YModule
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module
→
get_upTime() module
→
upTime()
Returns the number of milliseconds spent since the module was powered on.
js function get_upTime( ) nodejs function get_upTime( ) php cpp m pas function get_upTime( ) s64 get_upTime( )
-(s64) upTime function get_upTime( ): int64 vb cs java py cmd function get_upTime( ) As Long long get_upTime( ) long get_upTime( ) def get_upTime( )
YModule
target
get_upTime
Returns :
an integer corresponding to the number of milliseconds spent since the module was powered on
On failure, throws an exception or returns Y_UPTIME_INVALID .
YModule
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module
→
get_usbBandwidth() module
→
usbBandwidth()
Returns the number of USB interfaces used by the module.
js nodejs function get_usbBandwidth( ) function get_usbBandwidth( ) php cpp function get_usbBandwidth( )
Y_USBBANDWIDTH_enum get_usbBandwidth( ) m pas vb cs
-(Y_USBBANDWIDTH_enum) usbBandwidth function get_usbBandwidth( ): Integer function get_usbBandwidth( ) As Integer int get_usbBandwidth( ) java py cmd int get_usbBandwidth( ) def get_usbBandwidth( )
YModule
target
get_usbBandwidth
21. High-level API Reference
YModule
Returns :
either Y_USBBANDWIDTH_SIMPLE or Y_USBBANDWIDTH_DOUBLE , according to the number of
USB interfaces used by the module
On failure, throws an exception or returns
Y_USBBANDWIDTH_INVALID
.
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module
→
get_usbCurrent() module
→
usbCurrent()
Returns the current consumed by the module on the USB bus, in milli-amps.
js function get_usbCurrent( ) nodejs function get_usbCurrent( ) php cpp m pas function get_usbCurrent( ) int get_usbCurrent( )
-(int) usbCurrent function get_usbCurrent( ): LongInt vb cs java py cmd function get_usbCurrent( ) As Integer int get_usbCurrent( ) int get_usbCurrent( ) def get_usbCurrent( )
YModule
target
get_usbCurrent
Returns :
an integer corresponding to the current consumed by the module on the USB bus, in milli-amps
On failure, throws an exception or returns Y_USBCURRENT_INVALID .
YModule
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module
→
get_userData() module
→
userData()
YModule
Returns the value of the userData attribute, as previously stored using method set_userData
.
js function get_userData( ) nodejs function get_userData( ) php function get_userData( ) cpp m pas vb cs java py void * get_userData( )
-(void*) userData function get_userData( ): Tobject function get_userData( ) As Object object get_userData( )
Object get_userData( ) def get_userData( )
This attribute is never touched directly by the API, and is at disposal of the caller to store a context.
Returns :
the object stored previously by the caller.
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module
→
isOnline() YModule
Checks if the module is currently reachable, without raising any error.
js function isOnline( ) nodejs function isOnline( ) php function isOnline( ) cpp m pas vb cs java py bool isOnline( )
-(BOOL) isOnline function isOnline( ): boolean function isOnline( ) As Boolean bool isOnline( ) boolean isOnline( ) def isOnline( )
If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.
Returns :
true
if the module can be reached, and false
otherwise
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module
→
isOnline_async() YModule
Checks if the module is currently reachable, without raising any error.
js function isOnline_async(
callback
,
context
) nodejs function isOnline_async(
callback
,
context
)
If there are valid cached values for the module, that have not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the requested module.
This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox Javascript VM that does not implement context switching during blocking I/O calls.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the boolean result
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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module
→
load() YModule
Preloads the module cache with a specified validity duration.
js function load(
msValidity
) nodejs function load(
msValidity
) php function load(
$msValidity
) cpp m pas vb cs java py
YRETCODE load( int
msValidity
)
-(YRETCODE) load : (int)
msValidity
function load(
msValidity
: integer): YRETCODE function load( ByVal
msValidity
As Integer) As YRETCODE
YRETCODE load( int
msValidity
) int load( long
msValidity
) def load(
msValidity
)
By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance.
Parameters : msValidity
an integer corresponding to the validity attributed to the loaded module parameters, in milliseconds
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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module
→
load_async() YModule
Preloads the module cache with a specified validity duration (asynchronous version).
js function load_async(
msValidity
,
callback
,
context
) nodejs function load_async(
msValidity
,
callback
,
context
)
By default, whenever accessing a device, all module attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking I/O calls. See the documentation section on asynchronous
Javascript calls for more details.
Parameters : msValidity
an integer corresponding to the validity of the loaded module parameters, in milliseconds
callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving module object and the error code
(or
YAPI_SUCCESS
)
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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module
→
nextModule()
Continues the module enumeration started using yFirstModule()
.
js function nextModule( ) nodejs function nextModule( ) php cpp m pas function nextModule( )
YModule * nextModule( )
-(YModule*) nextModule function nextModule( ): TYModule vb cs java py function nextModule( ) As YModule
YModule nextModule( )
YModule nextModule( ) def nextModule( )
YModule
Returns :
a pointer to a
YModule
object, corresponding to the next module found, or a null
pointer if there are no more modules to enumerate.
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module
→
reboot()
Schedules a simple module reboot after the given number of seconds.
js function reboot(
secBeforeReboot
) nodejs function reboot(
secBeforeReboot
) php function reboot(
$secBeforeReboot
) cpp m pas vb cs java py cmd int reboot( int
secBeforeReboot
)
-(int) reboot : (int)
secBeforeReboot
function reboot(
secBeforeReboot
: LongInt): LongInt function reboot( ) As Integer int reboot( int
secBeforeReboot
) int reboot( int
secBeforeReboot
) def reboot(
secBeforeReboot
)
YModule
target
reboot
secBeforeReboot
21. High-level API Reference
YModule
Parameters : secBeforeReboot
number of seconds before rebooting
Returns :
YAPI_SUCCESS
when the call succeeds. On failure, throws an exception or returns a negative error code.
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module
→
revertFromFlash() YModule
Reloads the settings stored in the nonvolatile memory, as when the module is powered on.
js function revertFromFlash( ) nodejs function revertFromFlash( ) php function revertFromFlash( ) cpp m pas vb cs java py cmd int revertFromFlash( )
-(int) revertFromFlash function revertFromFlash( ): LongInt function revertFromFlash( ) As Integer int revertFromFlash( ) int revertFromFlash( ) def revertFromFlash( )
YModule
target
revertFromFlash
Returns :
YAPI_SUCCESS
when the call succeeds. On failure, throws an exception or returns a negative error code.
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module
→
saveToFlash() YModule
Saves current settings in the nonvolatile memory of the module.
js function saveToFlash( ) nodejs function saveToFlash( ) php function saveToFlash( ) cpp m pas vb cs java py cmd int saveToFlash( )
-(int) saveToFlash function saveToFlash( ): LongInt function saveToFlash( ) As Integer int saveToFlash( ) int saveToFlash( ) def saveToFlash( )
YModule
target
saveToFlash
Warning: the number of allowed save operations during a module life is limited (about 100000 cycles).
Do not call this function within a loop.
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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module
→
set_beacon() module
→
setBeacon()
Turns on or off the module localization beacon.
js function set_beacon(
newval
) nodejs function set_beacon(
newval
) php cpp m pas function set_beacon(
$newval
) int set_beacon( Y_BEACON_enum
newval
)
-(int) setBeacon : (Y_BEACON_enum)
newval
function set_beacon(
newval
: Integer): integer vb cs java py cmd function set_beacon( ByVal
newval
As Integer) As Integer int set_beacon( int
newval
) int set_beacon( int
newval
) def set_beacon(
newval
)
YModule
target
set_beacon
newval
Parameters : newval
either
Y_BEACON_OFF
or
Y_BEACON_ON
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
YModule
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module
→
set_logicalName() module
→
setLogicalName()
Changes the logical name of the module.
js nodejs function set_logicalName(
newval
) function set_logicalName(
newval
) php cpp function set_logicalName(
$newval
) int set_logicalName( const string&
newval
) m pas vb cs
-(int) setLogicalName : (NSString*)
newval
function set_logicalName(
newval
: string): integer function set_logicalName( ByVal
newval
As String) As Integer int set_logicalName( string
newval
) java py cmd int set_logicalName( String
newval
) def set_logicalName(
newval
)
YModule
target
set_logicalName
newval
YModule
You can use yCheckLogicalName()
prior to this call to make sure that your parameter is valid.
Remember to call the saveToFlash()
method of the module if the modification must be kept.
Parameters : newval
a string corresponding to the logical name of the module
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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module
→
set_luminosity() module
→
setLuminosity()
Changes the luminosity of the module informative leds.
js function set_luminosity(
newval
) nodejs function set_luminosity(
newval
) php cpp m pas function set_luminosity(
$newval
) int set_luminosity( int
newval
)
-(int) setLuminosity : (int)
newval
function set_luminosity(
newval
: LongInt): integer vb cs java py cmd function set_luminosity( ByVal
newval
As Integer) As Integer int set_luminosity( int
newval
) int set_luminosity( int
newval
) def set_luminosity(
newval
)
YModule
target
set_luminosity
newval
YModule
The parameter is a value between 0 and 100. Remember to call the saveToFlash()
method of the module if the modification must be kept.
Parameters : newval
an integer corresponding to the luminosity of the module informative leds
Returns :
YAPI_SUCCESS
if the call succeeds.
On failure, throws an exception or returns a negative error code.
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module
→
set_usbBandwidth() module
→
setUsbBandwidth()
Changes the number of USB interfaces used by the module.
js nodejs function set_usbBandwidth(
newval
) function set_usbBandwidth(
newval
) php cpp function set_usbBandwidth(
$newval
) int set_usbBandwidth( Y_USBBANDWIDTH_enum
newval
) m pas vb cs
-(int) setUsbBandwidth : (Y_USBBANDWIDTH_enum)
newval
function set_usbBandwidth(
newval
: Integer): integer function set_usbBandwidth( ByVal
newval
As Integer) As Integer int set_usbBandwidth( int
newval
) java py cmd int set_usbBandwidth( int
newval
) def set_usbBandwidth(
newval
)
YModule
target
set_usbBandwidth
newval
You must reboot the module after changing this setting.
21. High-level API Reference
YModule
Parameters : newval
either
Y_USBBANDWIDTH_SIMPLE
or
Y_USBBANDWIDTH_DOUBLE
, according to the number of USB interfaces used by the module
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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module
→
set_userData() module
→
setUserData()
Stores a user context provided as argument in the userData attribute of the function.
js function set_userData(
data
) nodejs function set_userData(
data
) php cpp m pas function set_userData(
$data
) void set_userData( void*
data
)
-(void) setUserData : (void*)
data
procedure set_userData(
data
: Tobject) vb cs java py procedure set_userData( ByVal
data
As Object) void set_userData( object
data
) void set_userData( Object
data
) def set_userData(
data
)
This attribute is never touched by the API, and is at disposal of the caller to store a context.
YModule
Parameters : data
any kind of object to be stored
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module
→
triggerFirmwareUpdate()
Schedules a module reboot into special firmware update mode.
js function triggerFirmwareUpdate(
secBeforeReboot
) nodejs function triggerFirmwareUpdate(
secBeforeReboot
) php function triggerFirmwareUpdate(
$secBeforeReboot
) cpp m pas vb cs java py cmd int triggerFirmwareUpdate( int
secBeforeReboot
)
-(int) triggerFirmwareUpdate : (int)
secBeforeReboot
function triggerFirmwareUpdate(
secBeforeReboot
: LongInt): LongInt function triggerFirmwareUpdate( ) As Integer int triggerFirmwareUpdate( int
secBeforeReboot
) int triggerFirmwareUpdate( int
secBeforeReboot
) def triggerFirmwareUpdate(
secBeforeReboot
)
YModule
target
triggerFirmwareUpdate
secBeforeReboot
21. High-level API Reference
YModule
Parameters : secBeforeReboot
number of seconds before rebooting
Returns :
YAPI_SUCCESS
when the call succeeds. On failure, throws an exception or returns a negative error code.
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module
→
wait_async() YModule
Waits for all pending asynchronous commands on the module to complete, and invoke the userprovided callback function.
js function wait_async(
callback
,
context
) nodejs function wait_async(
callback
,
context
)
The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.
Parameters : callback
callback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing.
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21. High-level API Reference
21.3. Current function interface
The Yoctopuce application programming interface allows you to read an instant measure of the sensor, as well as the minimal and maximal values observed.
In order to use the functions described here, you should include: js nodejs php cpp m pas vb cs java py
<script type='text/javascript' src='yocto_current.js'></script> var yoctolib = require('yoctolib'); var YCurrent = yoctolib.YCurrent; require_once('yocto_current.php');
#include "yocto_current.h"
#import "yocto_current.h" uses yocto_current; yocto_current.vb
yocto_current.cs
import com.yoctopuce.YoctoAPI.YCurrent; from yocto_current import *
Global functions
func
)
Retrieves a current sensor for a given identifier.
Starts the enumeration of current sensors currently accessible.
YCurrent
methods
rawValues
,
refValues
)
Configures error correction data points, in particular to compensate for a possible perturbation of the measure caused by an enclosure.
R e t u r n s a s h o r t t e x t t h a t d e s c r i b e s t h e c u r r e n t s e n s o r i n t h e f o r m
T Y P E ( N A M E ) = S E R I A L . F U N C T I O N I D
.
Returns the current value of the current sensor (no more than 6 characters).
Returns the uncalibrated, unrounded raw value returned by the sensor.
Returns the current measured value.
Returns the error message of the latest error with the current sensor.
Returns the numerical error code of the latest error with the current sensor.
Returns a global identifier of the current sensor in the format MODULE_NAME.FUNCTION_NAME
.
Returns a unique identifier of type YFUN_DESCR corresponding to the function.
Returns the hardware identifier of the current sensor, without reference to the module.
Returns the unique hardware identifier of the current sensor in the form
SERIAL.FUNCTIONID
.
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21. High-level API Reference
Returns the maximal value observed.
Returns the datalogger recording frequency for this function, or "OFF" when measures are not stored in the data logger flash memory.
Returns the logical name of the current sensor.
Returns the minimal value observed.
Gets the YModule object for the device on which the function is located.
callback
,
context
)
Gets the YModule object for the device on which the function is located (asynchronous version).
startTime
,
endTime
)
Retrieves a DataSet object holding historical data for this sensor, for a specified time interval.
Returns the timed value notification frequency, or "OFF" if timed value notifications are disabled for this function.
Returns the resolution of the measured values.
Returns the measuring unit for the measured value.
Returns the value of the userData attribute, as previously stored using method set_userData
.
Checks if the current sensor is currently reachable, without raising any error.
callback
,
context
)
Checks if the current sensor is currently reachable, without raising any error (asynchronous version).
msValidity
)
Preloads the current sensor cache with a specified validity duration.
rawValues
,
refValues
)
Retrieves error correction data points previously entered using the method calibrateFromPoints
.
msValidity
,
callback
,
context
)
Preloads the current sensor cache with a specified validity duration (asynchronous version).
Continues the enumeration of current sensors started using yFirstCurrent() .
callback
)
Registers the callback function that is invoked on every periodic timed notification.
callback
)
Registers the callback function that is invoked on every change of advertised value.
newval
)
Changes the recorded maximal value observed.
newval
)
Changes the datalogger recording frequency for this function.
newval
)
Changes the logical name of the current sensor.
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newval
)
Changes the recorded minimal value observed.
newval
)
Changes the timed value notification frequency for this function.
newval
)
Changes the resolution of the measured values.
data
)
Stores a user context provided as argument in the userData attribute of the function.
callback
,
context
)
Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.
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YCurrent.FindCurrent() yFindCurrent()
Retrieves a current sensor for a given identifier.
js function yFindCurrent(
func
) nodejs function FindCurrent(
func
) php cpp m pas function yFindCurrent(
$func
)
YCurrent* yFindCurrent( const string&
func
)
YCurrent* yFindCurrent( NSString*
func
) function yFindCurrent(
func
: string): TYCurrent vb cs java py function yFindCurrent( ByVal
func
As String) As YCurrent
YCurrent FindCurrent( string
func
)
YCurrent FindCurrent( String
func
) def FindCurrent(
func
)
The identifier can be specified using several formats:
YCurrent
●
FunctionLogicalName
●
ModuleSerialNumber.FunctionIdentifier
●
ModuleSerialNumber.FunctionLogicalName
●
ModuleLogicalName.FunctionIdentifier
●
ModuleLogicalName.FunctionLogicalName
This function does not require that the current sensor is online at the time it is invoked. The returned object is nevertheless valid. Use the method YCurrent.isOnline() to test if the current sensor is indeed online at a given time. In case of ambiguity when looking for a current sensor by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.
Parameters : func
a string that uniquely characterizes the current sensor
Returns :
a
YCurrent
object allowing you to drive the current sensor.
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YCurrent.FirstCurrent() yFirstCurrent()
21. High-level API Reference
YCurrent
Starts the enumeration of current sensors currently accessible.
js nodejs function yFirstCurrent( ) function FirstCurrent( ) php cpp function yFirstCurrent( )
YCurrent* yFirstCurrent( ) m pas vb cs java py
YCurrent* yFirstCurrent( ) function yFirstCurrent( ): TYCurrent function yFirstCurrent( ) As YCurrent
YCurrent FirstCurrent( )
YCurrent FirstCurrent( ) def FirstCurrent( )
Use the method
YCurrent.nextCurrent()
to iterate on next current sensors.
Returns :
a pointer to a YCurrent object, corresponding to the first current sensor currently online, or a null pointer if there are none.
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current
→
calibrateFromPoints() YCurrent
Configures error correction data points, in particular to compensate for a possible perturbation of the measure caused by an enclosure.
js cpp function calibrateFromPoints(
rawValues
,
refValues
) nodejs function calibrateFromPoints(
rawValues
,
refValues
) php function calibrateFromPoints(
$rawValues
,
$refValues
) int calibrateFromPoints( vector<double>
rawValues
, vector<double>
refValues
) m
-(int) calibrateFromPoints : (NSMutableArray*)
rawValues
: (NSMutableArray*)
refValues
pas function calibrateFromPoints(
rawValues
: TDoubleArray,
refValues
: TDoubleArray): LongInt vb cs procedure calibrateFromPoints( ) int calibrateFromPoints( List<double>
rawValues
,
List<double>
refValues
) java int calibrateFromPoints( ArrayList<Double>
rawValues
,
ArrayList<Double>
refValues
) py cmd def calibrateFromPoints(
rawValues
,
refValues
)
YCurrent
target
calibrateFromPoints
rawValues refValues
It is possible to configure up to five correction points. Correction points must be provided in ascending order, and be in the range of the sensor. The device will automatically perform a linear interpolation of the error correction between specified points. Remember to call the saveToFlash() method of the module if the modification must be kept.
For more information on advanced capabilities to refine the calibration of sensors, please contact [email protected].
Parameters : rawValues
array of floating point numbers, corresponding to the raw values returned by the sensor for the correction points.
refValues
array of floating point numbers, corresponding to the corrected
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current
→
describe() YCurrent
R e t u r n s a s h o r t t e x t t h a t d e s c r i b e s t h e c u r r e n t s e n s o r i n t h e f o r m
T Y P E ( N A M E ) = S E R I A L . F U N C T I O N I D
.
js nodejs function describe( ) function describe( ) php cpp function describe( ) string describe( ) m pas vb cs java py
-(NSString*) describe function describe( ): string function describe( ) As String string describe( )
String describe( ) def describe( )
More precisely,
TYPE
is the type of the function,
NAME
it the name used for the first access to the function,
SERIAL
is the serial number of the module if the module is connected or
"unresolved"
, and
FUNCTIONID
is the hardware identifier of the function if the module is connected. For example, this method returns Relay(MyCustomName.relay1)=RELAYLO1-123456.relay1
if the module is already connected or
Relay(BadCustomeName.relay1)=unresolved
if the module has not yet been connected. This method does not trigger any USB or TCP transaction and can therefore be used in a debugger.
Returns :
a string that describes the current sensor (ex:
Relay(MyCustomName.relay1)=RELAYLO1-
123456.relay1
)
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21. High-level API Reference
current
→
get_advertisedValue() current
→
advertisedValue()
Returns the current value of the current sensor (no more than 6 characters).
js function get_advertisedValue( ) nodejs function get_advertisedValue( ) php cpp m pas function get_advertisedValue( ) string get_advertisedValue( )
-(NSString*) advertisedValue function get_advertisedValue( ): string vb cs java py cmd function get_advertisedValue( ) As String string get_advertisedValue( )
String get_advertisedValue( ) def get_advertisedValue( )
YCurrent
target
get_advertisedValue
YCurrent
Returns :
a string corresponding to the current value of the current sensor (no more than 6 characters). On failure, throws an exception or returns
Y_ADVERTISEDVALUE_INVALID
.
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current
→
get_currentRawValue() current
→
currentRawValue()
Returns the uncalibrated, unrounded raw value returned by the sensor.
js nodejs function get_currentRawValue( ) function get_currentRawValue( ) php cpp function get_currentRawValue( ) double get_currentRawValue( ) m pas vb cs
-(double) currentRawValue function get_currentRawValue( ): double function get_currentRawValue( ) As Double double get_currentRawValue( ) java py cmd double get_currentRawValue( ) def get_currentRawValue( )
YCurrent
target
get_currentRawValue
21. High-level API Reference
YCurrent
Returns :
a floating point number corresponding to the uncalibrated, unrounded raw value returned by the sensor
On failure, throws an exception or returns Y_CURRENTRAWVALUE_INVALID .
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current
→
get_currentValue() current
→
currentValue()
Returns the current measured value.
js function get_currentValue( ) nodejs function get_currentValue( ) php cpp m pas function get_currentValue( ) double get_currentValue( )
-(double) currentValue function get_currentValue( ): double vb cs java py cmd function get_currentValue( ) As Double double get_currentValue( ) double get_currentValue( ) def get_currentValue( )
YCurrent
target
get_currentValue
Returns :
a floating point number corresponding to the current measured value
On failure, throws an exception or returns Y_CURRENTVALUE_INVALID .
YCurrent
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21. High-level API Reference
current
→
get_errorMessage() current
→
errorMessage()
Returns the error message of the latest error with the current sensor.
js nodejs function get_errorMessage( ) function get_errorMessage( ) php cpp function get_errorMessage( ) string get_errorMessage( ) m pas vb cs java py
-(NSString*) errorMessage function get_errorMessage( ): string function get_errorMessage( ) As String string get_errorMessage( )
String get_errorMessage( ) def get_errorMessage( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
YCurrent
Returns :
a string corresponding to the latest error message that occured while using the current sensor object
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current
→
get_errorType() current
→
errorType()
Returns the numerical error code of the latest error with the current sensor.
js function get_errorType( ) nodejs function get_errorType( ) php cpp pas vb function get_errorType( )
YRETCODE get_errorType( ) function get_errorType( ): YRETCODE function get_errorType( ) As YRETCODE cs java py
YRETCODE get_errorType( ) int get_errorType( ) def get_errorType( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
YCurrent
Returns :
a number corresponding to the code of the latest error that occured while using the current sensor object
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current
→
get_friendlyName() current
→
friendlyName()
YCurrent
Returns a global identifier of the current sensor in the format
MODULE_NAME.FUNCTION_NAME
.
js function get_friendlyName( ) nodejs function get_friendlyName( ) php function get_friendlyName( ) cpp m cs java py string get_friendlyName( )
-(NSString*) friendlyName string get_friendlyName( )
String get_friendlyName( ) def get_friendlyName( )
The returned string uses the logical names of the module and of the current sensor if they are defined, otherwise the serial number of the module and the hardware identifier of the current sensor (for exemple:
MyCustomName.relay1
)
Returns :
a string that uniquely identifies the current sensor using logical names (ex: MyCustomName.relay1
)
On failure, throws an exception or returns
Y_FRIENDLYNAME_INVALID
.
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21. High-level API Reference
current
→
get_functionDescriptor() current
→
functionDescriptor()
YCurrent
Returns a unique identifier of type
YFUN_DESCR
corresponding to the function.
js function get_functionDescriptor( ) nodejs function get_functionDescriptor( ) php function get_functionDescriptor( ) cpp m pas vb cs java py
YFUN_DESCR get_functionDescriptor( )
-(YFUN_DESCR) functionDescriptor function get_functionDescriptor( ): YFUN_DESCR function get_functionDescriptor( ) As YFUN_DESCR
YFUN_DESCR get_functionDescriptor( )
String get_functionDescriptor( ) def get_functionDescriptor( )
This identifier can be used to test if two instances of
YFunction
reference the same physical function on the same physical device.
Returns :
an identifier of type YFUN_DESCR . If the function has never been contacted, the returned value is
Y_FUNCTIONDESCRIPTOR_INVALID
.
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current
→
get_functionId() current
→
functionId()
Returns the hardware identifier of the current sensor, without reference to the module.
js nodejs function get_functionId( ) function get_functionId( ) php cpp function get_functionId( ) string get_functionId( ) m vb cs java py
-(NSString*) functionId function get_functionId( ) As String string get_functionId( )
String get_functionId( ) def get_functionId( )
YCurrent
For example relay1
Returns :
a string that identifies the current sensor (ex: relay1 ) On failure, throws an exception or returns
Y_FUNCTIONID_INVALID
.
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21. High-level API Reference
current
→
get_hardwareId() current
→
hardwareId()
YCurrent
Returns the unique hardware identifier of the current sensor in the form
SERIAL.FUNCTIONID
.
js function get_hardwareId( ) nodejs function get_hardwareId( ) php function get_hardwareId( ) cpp m vb cs java py string get_hardwareId( )
-(NSString*) hardwareId function get_hardwareId( ) As String string get_hardwareId( )
String get_hardwareId( ) def get_hardwareId( )
The unique hardware identifier is composed of the device serial number and of the hardware identifier of the current sensor. (for example
RELAYLO1-123456.relay1
)
Returns :
a string that uniquely identifies the current sensor (ex:
RELAYLO1-123456.relay1
) On failure, throws an exception or returns Y_HARDWAREID_INVALID .
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current
→
get_highestValue() current
→
highestValue()
Returns the maximal value observed.
js nodejs function get_highestValue( ) function get_highestValue( ) php cpp function get_highestValue( ) double get_highestValue( ) m pas vb cs
-(double) highestValue function get_highestValue( ): double function get_highestValue( ) As Double double get_highestValue( ) java py cmd double get_highestValue( ) def get_highestValue( )
YCurrent
target
get_highestValue
Returns :
a floating point number corresponding to the maximal value observed
On failure, throws an exception or returns Y_HIGHESTVALUE_INVALID .
21. High-level API Reference
YCurrent
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current
→
get_logFrequency() current
→
logFrequency()
YCurrent
Returns the datalogger recording frequency for this function, or "OFF" when measures are not stored in the data logger flash memory.
js function get_logFrequency( ) nodejs function get_logFrequency( ) php cpp m pas function get_logFrequency( ) string get_logFrequency( )
-(NSString*) logFrequency function get_logFrequency( ): string vb cs java py cmd function get_logFrequency( ) As String string get_logFrequency( )
String get_logFrequency( ) def get_logFrequency( )
YCurrent
target
get_logFrequency
Returns :
a string corresponding to the datalogger recording frequency for this function, or "OFF" when measures are not stored in the data logger flash memory
On failure, throws an exception or returns
Y_LOGFREQUENCY_INVALID
.
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current
→
get_logicalName() current
→
logicalName()
Returns the logical name of the current sensor.
js nodejs function get_logicalName( ) function get_logicalName( ) php cpp function get_logicalName( ) string get_logicalName( ) m pas vb cs
-(NSString*) logicalName function get_logicalName( ): string function get_logicalName( ) As String string get_logicalName( ) java py cmd
String get_logicalName( ) def get_logicalName( )
YCurrent
target
get_logicalName
21. High-level API Reference
YCurrent
Returns :
a string corresponding to the logical name of the current sensor. On failure, throws an exception or returns
Y_LOGICALNAME_INVALID
.
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current
→
get_lowestValue() current
→
lowestValue()
Returns the minimal value observed.
js function get_lowestValue( ) nodejs function get_lowestValue( ) php cpp m pas function get_lowestValue( ) double get_lowestValue( )
-(double) lowestValue function get_lowestValue( ): double vb cs java py cmd function get_lowestValue( ) As Double double get_lowestValue( ) double get_lowestValue( ) def get_lowestValue( )
YCurrent
target
get_lowestValue
Returns :
a floating point number corresponding to the minimal value observed
On failure, throws an exception or returns Y_LOWESTVALUE_INVALID .
YCurrent
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current
→
get_module() current
→
module()
YCurrent
Gets the
YModule
object for the device on which the function is located.
js function get_module( ) nodejs function get_module( ) php function get_module( ) cpp m pas vb cs java py
YModule * get_module( )
-(YModule*) module function get_module( ): TYModule function get_module( ) As YModule
YModule get_module( )
YModule get_module( ) def get_module( )
If the function cannot be located on any module, the returned instance of
YModule
is not shown as online.
Returns :
an instance of YModule
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21. High-level API Reference
current
→
get_module_async() current
→
module_async()
YCurrent
Gets the
YModule
object for the device on which the function is located (asynchronous version).
js function get_module_async(
callback
,
context
) nodejs function get_module_async(
callback
,
context
)
If the function cannot be located on any module, the returned
YModule
object does not show as online. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking
I/O calls. See the documentation section on asynchronous Javascript calls for more details.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the requested
YModule object
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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current
→
get_recordedData() current
→
recordedData()
YCurrent
Retrieves a DataSet object holding historical data for this sensor, for a specified time interval.
js nodejs function get_recordedData(
startTime
,
endTime
) function get_recordedData(
startTime
,
endTime
) php cpp m function get_recordedData(
$startTime
,
$endTime
)
YDataSet get_recordedData( s64
startTime
, s64
endTime
)
-(YDataSet*) recordedData : (s64)
startTime
: (s64)
endTime
pas vb cs function get_recordedData(
startTime
: int64,
endTime
: int64): TYDataSet function get_recordedData( ) As YDataSet
YDataSet get_recordedData( long
startTime
, long
endTime
) java py cmd
YDataSet get_recordedData( long
startTime
, long
endTime
) def get_recordedData(
startTime
,
endTime
)
YCurrent
target
get_recordedData
startTime endTime
The measures will be retrieved from the data logger, which must have been turned on at the desired time. See the documentation of the DataSet class for information on how to get an overview of the recorded data, and how to load progressively a large set of measures from the data logger.
This function only works if the device uses a recent firmware, as DataSet objects are not supported by firmwares older than version 13000.
Parameters : startTime
the start of the desired measure time interval, as a Unix timestamp, i.e. the number of seconds since January 1, 1970 UTC. The special value 0 can be used to include any meaasure, without initial limit.
endTime
the end of the desired measure time interval, as a Unix timestamp, i.e. the number of seconds since January 1, 1970 UTC. The special value 0 can be used to include any meaasure, without ending limit.
Returns :
an instance of YDataSet, providing access to historical data. Past measures can be loaded progressively using methods from the YDataSet object.
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current
→
get_reportFrequency() current
→
reportFrequency()
YCurrent
Returns the timed value notification frequency, or "OFF" if timed value notifications are disabled for this function.
js function get_reportFrequency( ) nodejs function get_reportFrequency( ) php cpp m pas function get_reportFrequency( ) string get_reportFrequency( )
-(NSString*) reportFrequency function get_reportFrequency( ): string vb cs java py cmd function get_reportFrequency( ) As String string get_reportFrequency( )
String get_reportFrequency( ) def get_reportFrequency( )
YCurrent
target
get_reportFrequency
Returns :
a string corresponding to the timed value notification frequency, or "OFF" if timed value notifications are disabled for this function
On failure, throws an exception or returns
Y_REPORTFREQUENCY_INVALID
.
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current
→
get_resolution() current
→
resolution()
YCurrent
Returns the resolution of the measured values.
js nodejs function get_resolution( ) function get_resolution( ) php cpp function get_resolution( ) double get_resolution( ) m pas vb cs
-(double) resolution function get_resolution( ): double function get_resolution( ) As Double double get_resolution( ) java py cmd double get_resolution( ) def get_resolution( )
YCurrent
target
get_resolution
The resolution corresponds to the numerical precision of the measures, which is not always the same as the actual precision of the sensor.
Returns :
a floating point number corresponding to the resolution of the measured values
On failure, throws an exception or returns Y_RESOLUTION_INVALID .
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current
→
get_unit() current
→
unit()
Returns the measuring unit for the measured value.
js function get_unit( ) nodejs function get_unit( ) php cpp m pas function get_unit( ) string get_unit( )
-(NSString*) unit function get_unit( ): string vb cs java py cmd function get_unit( ) As String string get_unit( )
String get_unit( ) def get_unit( )
YCurrent
target
get_unit
Returns :
a string corresponding to the measuring unit for the measured value
On failure, throws an exception or returns Y_UNIT_INVALID .
YCurrent
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current
→
get_userData() current
→
userData()
YCurrent
Returns the value of the userData attribute, as previously stored using method set_userData
.
js function get_userData( ) nodejs function get_userData( ) php function get_userData( ) cpp m pas vb cs java py void * get_userData( )
-(void*) userData function get_userData( ): Tobject function get_userData( ) As Object object get_userData( )
Object get_userData( ) def get_userData( )
This attribute is never touched directly by the API, and is at disposal of the caller to store a context.
Returns :
the object stored previously by the caller.
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current
→
isOnline() YCurrent
Checks if the current sensor is currently reachable, without raising any error.
js function isOnline( ) nodejs function isOnline( ) php function isOnline( ) cpp m pas vb cs java py bool isOnline( )
-(BOOL) isOnline function isOnline( ): boolean function isOnline( ) As Boolean bool isOnline( ) boolean isOnline( ) def isOnline( )
If there is a cached value for the current sensor in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the current sensor.
Returns :
true
if the current sensor can be reached, and false
otherwise
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current
→
isOnline_async() YCurrent
Checks if the current sensor is currently reachable, without raising any error (asynchronous version).
js function isOnline_async(
callback
,
context
) nodejs function isOnline_async(
callback
,
context
)
If there is a cached value for the current sensor in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the requested function.
This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the boolean result
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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current
→
load() YCurrent
Preloads the current sensor cache with a specified validity duration.
js function load(
msValidity
) nodejs function load(
msValidity
) php function load(
$msValidity
) cpp m pas vb cs java py
YRETCODE load( int
msValidity
)
-(YRETCODE) load : (int)
msValidity
function load(
msValidity
: integer): YRETCODE function load( ByVal
msValidity
As Integer) As YRETCODE
YRETCODE load( int
msValidity
) int load( long
msValidity
) def load(
msValidity
)
By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance.
Parameters : msValidity
an integer corresponding to the validity attributed to the loaded function parameters, in milliseconds
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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current
→
loadCalibrationPoints() YCurrent
R e t r i e v e s e r r o r c o r r e c t i o n d a t a p o i n t s p r e v i o u s l y e n t e r e d u s i n g t h e m e t h o d c a l i b r a t e F r o m P o i n t s
.
js nodejs function loadCalibrationPoints(
rawValues
,
refValues
) function loadCalibrationPoints(
rawValues
,
refValues
) php cpp function loadCalibrationPoints(
&$rawValues
,
&$refValues
) int loadCalibrationPoints( vector<double>&
rawValues
, vector<double>&
refValues
) m
-(int) loadCalibrationPoints : (NSMutableArray*)
rawValues
: (NSMutableArray*)
refValues
pas function loadCalibrationPoints( var
rawValues
: TDoubleArray, var
refValues
: TDoubleArray): LongInt vb cs procedure loadCalibrationPoints( ) int loadCalibrationPoints( List<double>
rawValues
,
List<double>
refValues
) java int loadCalibrationPoints( ArrayList<Double>
rawValues
,
ArrayList<Double>
refValues
) py cmd def loadCalibrationPoints(
rawValues
,
refValues
)
YCurrent
target
loadCalibrationPoints
rawValues refValues
Parameters : rawValues
array of floating point numbers, that will be filled by the function with the raw sensor values for the correction points.
refValues
array of floating point numbers, that will be filled by the function with the desired values for the correction points.
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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current
→
load_async() YCurrent
Preloads the current sensor cache with a specified validity duration (asynchronous version).
js function load_async(
msValidity
,
callback
,
context
) nodejs function load_async(
msValidity
,
callback
,
context
)
By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.
Parameters : msValidity
an integer corresponding to the validity of the loaded function parameters, in milliseconds
callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the error code
(or
YAPI_SUCCESS
)
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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current
→
nextCurrent()
Continues the enumeration of current sensors started using yFirstCurrent()
.
js nodejs function nextCurrent( ) function nextCurrent( ) php cpp function nextCurrent( )
YCurrent * nextCurrent( ) m pas vb cs java py
-(YCurrent*) nextCurrent function nextCurrent( ): TYCurrent function nextCurrent( ) As YCurrent
YCurrent nextCurrent( )
YCurrent nextCurrent( ) def nextCurrent( )
YCurrent
Returns :
a pointer to a
YCurrent
object, corresponding to a current sensor currently online, or a null
pointer if there are no more current sensors to enumerate.
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current
→
registerTimedReportCallback()
Registers the callback function that is invoked on every periodic timed notification.
js function registerTimedReportCallback(
callback
) nodejs function registerTimedReportCallback(
callback
) php function registerTimedReportCallback(
$callback
) cpp m pas vb cs java py int registerTimedReportCallback( YCurrentTimedReportCallback
callback
)
-(int) registerTimedReportCallback : (YCurrentTimedReportCallback)
callback
function registerTimedReportCallback(
callback
: TYCurrentTimedReportCallback): LongInt function registerTimedReportCallback( ) As Integer int registerTimedReportCallback( TimedReportCallback
callback
) int registerTimedReportCallback( TimedReportCallback
callback
) def registerTimedReportCallback(
callback
)
YCurrent
The callback is invoked only during the execution of ySleep
or yHandleEvents
. This provides control over the time when the callback is triggered. For good responsiveness, remember to call one of these two functions periodically. To unregister a callback, pass a null pointer as argument.
Parameters : callback
the callback function to call, or a null pointer. The callback function should take two arguments: the function object of which the value has changed, and an YMeasure object describing the new advertised value.
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current
→
registerValueCallback()
Registers the callback function that is invoked on every change of advertised value.
js function registerValueCallback(
callback
) nodejs function registerValueCallback(
callback
) php function registerValueCallback(
$callback
) cpp m pas vb cs java py int registerValueCallback( YCurrentValueCallback
callback
)
-(int) registerValueCallback : (YCurrentValueCallback)
callback
function registerValueCallback(
callback
: TYCurrentValueCallback): LongInt function registerValueCallback( ) As Integer int registerValueCallback( ValueCallback
callback
) int registerValueCallback( UpdateCallback
callback
) def registerValueCallback(
callback
)
YCurrent
The callback is invoked only during the execution of ySleep
or yHandleEvents
. This provides control over the time when the callback is triggered. For good responsiveness, remember to call one of these two functions periodically. To unregister a callback, pass a null pointer as argument.
Parameters : callback
the callback function to call, or a null pointer. The callback function should take two arguments: the function object of which the value has changed, and the character string describing the new advertised value.
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current
→
set_highestValue() current
→
setHighestValue()
Changes the recorded maximal value observed.
js function set_highestValue(
newval
) nodejs function set_highestValue(
newval
) php cpp m pas function set_highestValue(
$newval
) int set_highestValue( double
newval
)
-(int) setHighestValue : (double)
newval
function set_highestValue(
newval
: double): integer vb cs java py cmd function set_highestValue( ByVal
newval
As Double) As Integer int set_highestValue( double
newval
) int set_highestValue( double
newval
) def set_highestValue(
newval
)
YCurrent
target
set_highestValue
newval
Parameters : newval
a floating point number corresponding to the recorded maximal value observed
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
YCurrent
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current
→
set_logFrequency() current
→
setLogFrequency()
YCurrent
Changes the datalogger recording frequency for this function.
js nodejs function set_logFrequency(
newval
) function set_logFrequency(
newval
) php cpp function set_logFrequency(
$newval
) int set_logFrequency( const string&
newval
) m pas vb cs
-(int) setLogFrequency : (NSString*)
newval
function set_logFrequency(
newval
: string): integer function set_logFrequency( ByVal
newval
As String) As Integer int set_logFrequency( string
newval
) java py cmd int set_logFrequency( String
newval
) def set_logFrequency(
newval
)
YCurrent
target
set_logFrequency
newval
The frequency can be specified as samples per second, as sample per minute (for instance "15/m") or in samples per hour (eg. "4/h"). To disable recording for this function, use the value "OFF".
Parameters : newval
a string corresponding to the datalogger recording frequency for this function
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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current
→
set_logicalName() current
→
setLogicalName()
Changes the logical name of the current sensor.
js function set_logicalName(
newval
) nodejs function set_logicalName(
newval
) php cpp m pas function set_logicalName(
$newval
) int set_logicalName( const string&
newval
)
-(int) setLogicalName : (NSString*)
newval
function set_logicalName(
newval
: string): integer vb cs java py cmd function set_logicalName( ByVal
newval
As String) As Integer int set_logicalName( string
newval
) int set_logicalName( String
newval
) def set_logicalName(
newval
)
YCurrent
target
set_logicalName
newval
YCurrent
You can use yCheckLogicalName()
prior to this call to make sure that your parameter is valid.
Remember to call the saveToFlash()
method of the module if the modification must be kept.
Parameters : newval
a string corresponding to the logical name of the current sensor.
Returns :
YAPI_SUCCESS if the call succeeds. On failure, throws an exception or returns a negative error code.
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current
→
set_lowestValue() current
→
setLowestValue()
Changes the recorded minimal value observed.
js nodejs function set_lowestValue(
newval
) function set_lowestValue(
newval
) php cpp function set_lowestValue(
$newval
) int set_lowestValue( double
newval
) m pas vb cs
-(int) setLowestValue : (double)
newval
function set_lowestValue(
newval
: double): integer function set_lowestValue( ByVal
newval
As Double) As Integer int set_lowestValue( double
newval
) java py cmd int set_lowestValue( double
newval
) def set_lowestValue(
newval
)
YCurrent
target
set_lowestValue
newval
Parameters : newval
a floating point number corresponding to the recorded minimal value observed
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
21. High-level API Reference
YCurrent
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current
→
set_reportFrequency() current
→
setReportFrequency()
YCurrent
Changes the timed value notification frequency for this function.
js function set_reportFrequency(
newval
) nodejs function set_reportFrequency(
newval
) php cpp m pas function set_reportFrequency(
$newval
) int set_reportFrequency( const string&
newval
)
-(int) setReportFrequency : (NSString*)
newval
function set_reportFrequency(
newval
: string): integer vb cs java py cmd function set_reportFrequency( ByVal
newval
As String) As Integer int set_reportFrequency( string
newval
) int set_reportFrequency( String
newval
) def set_reportFrequency(
newval
)
YCurrent
target
set_reportFrequency
newval
The frequency can be specified as samples per second, as sample per minute (for instance "15/m") or in samples per hour (eg. "4/h"). To disable timed value notifications for this function, use the value
"OFF".
Parameters : newval
a string corresponding to the timed value notification frequency for this function
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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current
→
set_resolution() current
→
setResolution()
YCurrent
Changes the resolution of the measured values.
js nodejs function set_resolution(
newval
) function set_resolution(
newval
) php cpp function set_resolution(
$newval
) int set_resolution( double
newval
) m pas vb cs
-(int) setResolution : (double)
newval
function set_resolution(
newval
: double): integer function set_resolution( ByVal
newval
As Double) As Integer int set_resolution( double
newval
) java py cmd int set_resolution( double
newval
) def set_resolution(
newval
)
YCurrent
target
set_resolution
newval
The resolution corresponds to the numerical precision when displaying value. It does not change the precision of the measure itself.
Parameters : newval
a floating point number corresponding to the resolution of the measured values
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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current
→
set_userData() current
→
setUserData()
Stores a user context provided as argument in the userData attribute of the function.
js function set_userData(
data
) nodejs function set_userData(
data
) php cpp m pas function set_userData(
$data
) void set_userData( void*
data
)
-(void) setUserData : (void*)
data
procedure set_userData(
data
: Tobject) vb cs java py procedure set_userData( ByVal
data
As Object) void set_userData( object
data
) void set_userData( Object
data
) def set_userData(
data
)
This attribute is never touched by the API, and is at disposal of the caller to store a context.
YCurrent
Parameters : data
any kind of object to be stored
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current
→
wait_async() YCurrent
Waits for all pending asynchronous commands on the module to complete, and invoke the userprovided callback function.
js function wait_async(
callback
,
context
) nodejs function wait_async(
callback
,
context
)
The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.
Parameters : callback
callback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing.
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21.4. DataLogger function interface
Yoctopuce sensors include a non-volatile memory capable of storing ongoing measured data automatically, without requiring a permanent connection to a computer. The DataLogger function controls the global parameters of the internal data logger.
In order to use the functions described here, you should include: js nodejs php cpp m
<script type='text/javascript' src='yocto_datalogger.js'></script> var yoctolib = require('yoctolib'); var YDataLogger = yoctolib.YDataLogger; require_once('yocto_datalogger.php');
#include "yocto_datalogger.h"
#import "yocto_datalogger.h" pas vb cs java py uses yocto_datalogger; yocto_datalogger.vb
yocto_datalogger.cs
import com.yoctopuce.YoctoAPI.YDataLogger; from yocto_datalogger import *
func
)
Retrieves a data logger for a given identifier.
Global functions
Starts the enumeration of data loggers currently accessible.
YDataLogger
methods
Returns a short text that describes the data logger in the form TYPE(NAME)=SERIAL.FUNCTIONID
.
Clears the data logger memory and discards all recorded data streams.
Returns the current value of the data logger (no more than 6 characters).
Returns the default activation state of the data logger on power up.
Returns the current run number, corresponding to the number of times the module was powered on with the dataLogger enabled at some point.
Returns a list of YDataSet objects that can be used to retrieve all measures stored by the data logger.
v
)
Builds a list of all data streams hold by the data logger (legacy method).
Returns the error message of the latest error with the data logger.
Returns the numerical error code of the latest error with the data logger.
Returns a global identifier of the data logger in the format MODULE_NAME.FUNCTION_NAME
.
Returns a unique identifier of type YFUN_DESCR corresponding to the function.
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Returns the hardware identifier of the data logger, without reference to the module.
Returns the unique hardware identifier of the data logger in the form SERIAL.FUNCTIONID
.
Returns the logical name of the data logger.
Gets the YModule object for the device on which the function is located.
callback
,
context
)
Gets the
YModule
object for the device on which the function is located (asynchronous version).
Returns the current activation state of the data logger.
Returns the Unix timestamp for current UTC time, if known.
Returns the value of the userData attribute, as previously stored using method set_userData .
Checks if the data logger is currently reachable, without raising any error.
callback
,
context
)
Checks if the data logger is currently reachable, without raising any error (asynchronous version).
msValidity
)
Preloads the data logger cache with a specified validity duration.
msValidity
,
callback
,
context
)
Preloads the data logger cache with a specified validity duration (asynchronous version).
Continues the enumeration of data loggers started using yFirstDataLogger() .
callback
)
Registers the callback function that is invoked on every change of advertised value.
newval
)
Changes the default activation state of the data logger on power up.
newval
)
Changes the logical name of the data logger.
newval
)
Changes the activation state of the data logger to start/stop recording data.
newval
)
Changes the current UTC time reference used for recorded data.
data
)
Stores a user context provided as argument in the userData attribute of the function.
callback
,
context
)
Waits for all pending asynchronous commands on the module to complete, and invoke the user-provided callback function.
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21. High-level API Reference
YDataLogger.FindDataLogger() yFindDataLogger()
Retrieves a data logger for a given identifier.
js function yFindDataLogger(
func
) nodejs function FindDataLogger(
func
) php cpp m pas function yFindDataLogger(
$func
)
YDataLogger* yFindDataLogger( string
func
)
+(YDataLogger*) yFindDataLogger : (NSString*)
func
function yFindDataLogger(
func
: string): TYDataLogger vb cs java py function yFindDataLogger( ByVal
func
As String) As YDataLogger
YDataLogger FindDataLogger( string
func
)
YDataLogger FindDataLogger( String
func
) def FindDataLogger(
func
)
The identifier can be specified using several formats:
YDataLogger
●
FunctionLogicalName
●
ModuleSerialNumber.FunctionIdentifier
●
ModuleSerialNumber.FunctionLogicalName
●
ModuleLogicalName.FunctionIdentifier
●
ModuleLogicalName.FunctionLogicalName
This function does not require that the data logger is online at the time it is invoked. The returned object is nevertheless valid. Use the method YDataLogger.isOnline() to test if the data logger is indeed online at a given time. In case of ambiguity when looking for a data logger by logical name, no error is notified: the first instance found is returned. The search is performed first by hardware name, then by logical name.
Parameters : func
a string that uniquely characterizes the data logger
Returns :
a
YDataLogger
object allowing you to drive the data logger.
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YDataLogger.FirstDataLogger() yFirstDataLogger()
YDataLogger
Starts the enumeration of data loggers currently accessible.
js nodejs function yFirstDataLogger( ) function FirstDataLogger( ) php cpp function yFirstDataLogger( )
YDataLogger* yFirstDataLogger( ) m pas vb cs java py
YDataLogger* yFirstDataLogger( ) function yFirstDataLogger( ): TYDataLogger function yFirstDataLogger( ) As YDataLogger
YDataLogger FirstDataLogger( )
YDataLogger FirstDataLogger( ) def FirstDataLogger( )
Use the method
YDataLogger.nextDataLogger()
to iterate on next data loggers.
Returns :
a pointer to a YDataLogger object, corresponding to the first data logger currently online, or a null pointer if there are none.
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datalogger
→
describe() YDataLogger
R e t u r n s a s h o r t t e x t t h a t d e s c r i b e s t h e d a t a l o g g e r i n t h e f o r m
T Y P E ( N A M E ) = S E R I A L . F U N C T I O N I D
.
js function describe( ) nodejs function describe( ) php cpp m pas function describe( ) string describe( )
-(NSString*) describe function describe( ): string vb cs java py function describe( ) As String string describe( )
String describe( ) def describe( )
More precisely,
TYPE
is the type of the function,
NAME
it the name used for the first access to the function,
SERIAL
is the serial number of the module if the module is connected or
"unresolved"
, and
FUNCTIONID
is the hardware identifier of the function if the module is connected. For example, this method returns Relay(MyCustomName.relay1)=RELAYLO1-123456.relay1
if the module is already connected or
Relay(BadCustomeName.relay1)=unresolved
if the module has not yet been connected. This method does not trigger any USB or TCP transaction and can therefore be used in a debugger.
Returns :
a string that describes the data logger (ex:
Relay(MyCustomName.relay1)=RELAYLO1-
123456.relay1
)
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datalogger
→
forgetAllDataStreams()
Clears the data logger memory and discards all recorded data streams.
js function forgetAllDataStreams( ) nodejs function forgetAllDataStreams( ) php function forgetAllDataStreams( ) cpp m pas vb cs java py cmd int forgetAllDataStreams( )
-(int) forgetAllDataStreams function forgetAllDataStreams( ): LongInt function forgetAllDataStreams( ) As Integer int forgetAllDataStreams( ) int forgetAllDataStreams( ) def forgetAllDataStreams( )
YDataLogger
target
forgetAllDataStreams
This method also resets the current run index to zero.
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
21. High-level API Reference
YDataLogger
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datalogger
→
get_advertisedValue() datalogger
→
advertisedValue()
Returns the current value of the data logger (no more than 6 characters).
js function get_advertisedValue( ) nodejs function get_advertisedValue( ) php cpp m pas function get_advertisedValue( ) string get_advertisedValue( )
-(NSString*) advertisedValue function get_advertisedValue( ): string vb cs java py cmd function get_advertisedValue( ) As String string get_advertisedValue( )
String get_advertisedValue( ) def get_advertisedValue( )
YDataLogger
target
get_advertisedValue
YDataLogger
Returns :
a string corresponding to the current value of the data logger (no more than 6 characters). On failure, throws an exception or returns
Y_ADVERTISEDVALUE_INVALID
.
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datalogger
→
get_autoStart() datalogger
→
autoStart()
Returns the default activation state of the data logger on power up.
js nodejs function get_autoStart( ) function get_autoStart( ) php cpp function get_autoStart( )
Y_AUTOSTART_enum get_autoStart( ) m pas vb cs
-(Y_AUTOSTART_enum) autoStart function get_autoStart( ): Integer function get_autoStart( ) As Integer int get_autoStart( ) java py cmd int get_autoStart( ) def get_autoStart( )
YDataLogger
target
get_autoStart
21. High-level API Reference
YDataLogger
Returns :
either Y_AUTOSTART_OFF or Y_AUTOSTART_ON , according to the default activation state of the data logger on power up
On failure, throws an exception or returns
Y_AUTOSTART_INVALID
.
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datalogger
→
get_currentRunIndex() datalogger
→
currentRunIndex()
YDataLogger
Returns the current run number, corresponding to the number of times the module was powered on with the dataLogger enabled at some point.
js function get_currentRunIndex( ) nodejs function get_currentRunIndex( ) php cpp m pas function get_currentRunIndex( ) int get_currentRunIndex( )
-(int) currentRunIndex function get_currentRunIndex( ): LongInt vb cs java py cmd function get_currentRunIndex( ) As Integer int get_currentRunIndex( ) int get_currentRunIndex( ) def get_currentRunIndex( )
YDataLogger
target
get_currentRunIndex
Returns :
an integer corresponding to the current run number, corresponding to the number of times the module was powered on with the dataLogger enabled at some point
On failure, throws an exception or returns
Y_CURRENTRUNINDEX_INVALID
.
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datalogger
→
get_dataSets() datalogger
→
dataSets()
YDataLogger
Returns a list of YDataSet objects that can be used to retrieve all measures stored by the data logger.
js nodejs function get_dataSets( ) function get_dataSets( ) php cpp function get_dataSets( ) vector<YDataSet> get_dataSets( ) m pas vb cs
-(NSMutableArray*) dataSets function get_dataSets( ): TYDataSetArray function get_dataSets( ) As List
List<YDataSet> get_dataSets( ) java py cmd
ArrayList<YDataSet> get_dataSets( ) def get_dataSets( )
YDataLogger
target
get_dataSets
This function only works if the device uses a recent firmware, as YDataSet objects are not supported by firmwares older than version 13000.
Returns :
a list of YDataSet object.
On failure, throws an exception or returns an empty list.
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datalogger
→
get_dataStreams() datalogger
→
dataStreams()
YDataLogger
Builds a list of all data streams hold by the data logger (legacy method).
js function get_dataStreams(
v
) nodejs function get_dataStreams(
v
) php cpp m pas function get_dataStreams(
&$v
) int get_dataStreams( )
-(int) dataStreams : (NSArray**)
v
function get_dataStreams(
v
: Tlist): integer vb cs java py procedure get_dataStreams( ByVal
v
As List) int get_dataStreams( List<YDataStream>
v
) int get_dataStreams( ArrayList<YDataStream>
v
) def get_dataStreams(
v
)
The caller must pass by reference an empty array to hold YDataStream objects, and the function fills it with objects describing available data sequences.
This is the old way to retrieve data from the DataLogger. For new applications, you should rather use get_dataSets()
method, or call directly get_recordedData()
on the sensor object.
Parameters : v
an array of YDataStream objects to be filled in
Returns :
YAPI_SUCCESS
if the call succeeds.
On failure, throws an exception or returns a negative error code.
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datalogger
→
get_errorMessage() datalogger
→
errorMessage()
YDataLogger
Returns the error message of the latest error with the data logger.
js nodejs function get_errorMessage( ) function get_errorMessage( ) php cpp function get_errorMessage( ) string get_errorMessage( ) m pas vb cs java py
-(NSString*) errorMessage function get_errorMessage( ): string function get_errorMessage( ) As String string get_errorMessage( )
String get_errorMessage( ) def get_errorMessage( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
Returns :
a string corresponding to the latest error message that occured while using the data logger object
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datalogger
→
get_errorType() datalogger
→
errorType()
YDataLogger
Returns the numerical error code of the latest error with the data logger.
js function get_errorType( ) nodejs function get_errorType( ) php cpp pas vb function get_errorType( )
YRETCODE get_errorType( ) function get_errorType( ): YRETCODE function get_errorType( ) As YRETCODE cs java py
YRETCODE get_errorType( ) int get_errorType( ) def get_errorType( )
This method is mostly useful when using the Yoctopuce library with exceptions disabled.
Returns :
a number corresponding to the code of the latest error that occured while using the data logger object
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datalogger
→
get_friendlyName() datalogger
→
friendlyName()
YDataLogger
Returns a global identifier of the data logger in the format
MODULE_NAME.FUNCTION_NAME
.
js function get_friendlyName( ) nodejs function get_friendlyName( ) php function get_friendlyName( ) cpp m cs java py string get_friendlyName( )
-(NSString*) friendlyName string get_friendlyName( )
String get_friendlyName( ) def get_friendlyName( )
The returned string uses the logical names of the module and of the data logger if they are defined, otherwise the serial number of the module and the hardware identifier of the data logger (for exemple:
MyCustomName.relay1
)
Returns :
a string that uniquely identifies the data logger using logical names (ex: MyCustomName.relay1
) On failure, throws an exception or returns
Y_FRIENDLYNAME_INVALID
.
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datalogger
→
get_functionDescriptor() datalogger
→
functionDescriptor()
YDataLogger
Returns a unique identifier of type
YFUN_DESCR
corresponding to the function.
js function get_functionDescriptor( ) nodejs function get_functionDescriptor( ) php function get_functionDescriptor( ) cpp m pas vb cs java py
YFUN_DESCR get_functionDescriptor( )
-(YFUN_DESCR) functionDescriptor function get_functionDescriptor( ): YFUN_DESCR function get_functionDescriptor( ) As YFUN_DESCR
YFUN_DESCR get_functionDescriptor( )
String get_functionDescriptor( ) def get_functionDescriptor( )
This identifier can be used to test if two instances of
YFunction
reference the same physical function on the same physical device.
Returns :
an identifier of type YFUN_DESCR . If the function has never been contacted, the returned value is
Y_FUNCTIONDESCRIPTOR_INVALID
.
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datalogger
→
get_functionId() datalogger
→
functionId()
Returns the hardware identifier of the data logger, without reference to the module.
js nodejs function get_functionId( ) function get_functionId( ) php cpp function get_functionId( ) string get_functionId( ) m vb cs java py
-(NSString*) functionId function get_functionId( ) As String string get_functionId( )
String get_functionId( ) def get_functionId( )
YDataLogger
For example relay1
Returns :
a string that identifies the data logger (ex: relay1 ) On failure, throws an exception or returns
Y_FUNCTIONID_INVALID
.
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datalogger
→
get_hardwareId() datalogger
→
hardwareId()
YDataLogger
Returns the unique hardware identifier of the data logger in the form
SERIAL.FUNCTIONID
.
js function get_hardwareId( ) nodejs function get_hardwareId( ) php function get_hardwareId( ) cpp m vb cs java py string get_hardwareId( )
-(NSString*) hardwareId function get_hardwareId( ) As String string get_hardwareId( )
String get_hardwareId( ) def get_hardwareId( )
The unique hardware identifier is composed of the device serial number and of the hardware identifier of the data logger. (for example
RELAYLO1-123456.relay1
)
Returns :
a string that uniquely identifies the data logger (ex:
RELAYLO1-123456.relay1
) On failure, throws an exception or returns Y_HARDWAREID_INVALID .
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datalogger
→
get_logicalName() datalogger
→
logicalName()
Returns the logical name of the data logger.
js nodejs function get_logicalName( ) function get_logicalName( ) php cpp function get_logicalName( ) string get_logicalName( ) m pas vb cs
-(NSString*) logicalName function get_logicalName( ): string function get_logicalName( ) As String string get_logicalName( ) java py cmd
String get_logicalName( ) def get_logicalName( )
YDataLogger
target
get_logicalName
21. High-level API Reference
YDataLogger
Returns :
a string corresponding to the logical name of the data logger. On failure, throws an exception or returns
Y_LOGICALNAME_INVALID
.
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datalogger
→
get_module() datalogger
→
module()
YDataLogger
Gets the
YModule
object for the device on which the function is located.
js function get_module( ) nodejs function get_module( ) php function get_module( ) cpp m pas vb cs java py
YModule * get_module( )
-(YModule*) module function get_module( ): TYModule function get_module( ) As YModule
YModule get_module( )
YModule get_module( ) def get_module( )
If the function cannot be located on any module, the returned instance of
YModule
is not shown as online.
Returns :
an instance of YModule
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datalogger
→
get_module_async() datalogger
→
module_async()
YDataLogger
Gets the
YModule
object for the device on which the function is located (asynchronous version).
js function get_module_async(
callback
,
context
) nodejs function get_module_async(
callback
,
context
)
If the function cannot be located on any module, the returned
YModule
object does not show as online. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking Firefox javascript VM that does not implement context switching during blocking
I/O calls. See the documentation section on asynchronous Javascript calls for more details.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the requested
YModule object
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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datalogger
→
get_recording() datalogger
→
recording()
Returns the current activation state of the data logger.
js function get_recording( ) nodejs function get_recording( ) php cpp m pas function get_recording( )
Y_RECORDING_enum get_recording( )
-(Y_RECORDING_enum) recording function get_recording( ): Integer vb cs java py cmd function get_recording( ) As Integer int get_recording( ) int get_recording( ) def get_recording( )
YDataLogger
target
get_recording
YDataLogger
Returns :
either Y_RECORDING_OFF or Y_RECORDING_ON , according to the current activation state of the data logger
On failure, throws an exception or returns
Y_RECORDING_INVALID
.
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→
get_timeUTC() datalogger
→
timeUTC()
Returns the Unix timestamp for current UTC time, if known.
js nodejs function get_timeUTC( ) function get_timeUTC( ) php cpp function get_timeUTC( ) s64 get_timeUTC( ) m pas vb cs
-(s64) timeUTC function get_timeUTC( ): int64 function get_timeUTC( ) As Long long get_timeUTC( ) java py cmd long get_timeUTC( ) def get_timeUTC( )
YDataLogger
target
get_timeUTC
Returns :
an integer corresponding to the Unix timestamp for current UTC time, if known
On failure, throws an exception or returns Y_TIMEUTC_INVALID .
21. High-level API Reference
YDataLogger
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datalogger
→
get_userData() datalogger
→
userData()
YDataLogger
Returns the value of the userData attribute, as previously stored using method set_userData
.
js function get_userData( ) nodejs function get_userData( ) php function get_userData( ) cpp m pas vb cs java py void * get_userData( )
-(void*) userData function get_userData( ): Tobject function get_userData( ) As Object object get_userData( )
Object get_userData( ) def get_userData( )
This attribute is never touched directly by the API, and is at disposal of the caller to store a context.
Returns :
the object stored previously by the caller.
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datalogger
→
isOnline() YDataLogger
Checks if the data logger is currently reachable, without raising any error.
js function isOnline( ) nodejs function isOnline( ) php function isOnline( ) cpp m pas vb cs java py bool isOnline( )
-(BOOL) isOnline function isOnline( ): boolean function isOnline( ) As Boolean bool isOnline( ) boolean isOnline( ) def isOnline( )
If there is a cached value for the data logger in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the data logger.
Returns :
true
if the data logger can be reached, and false
otherwise
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datalogger
→
isOnline_async() YDataLogger
Checks if the data logger is currently reachable, without raising any error (asynchronous version).
js function isOnline_async(
callback
,
context
) nodejs function isOnline_async(
callback
,
context
)
If there is a cached value for the data logger in cache, that has not yet expired, the device is considered reachable. No exception is raised if there is an error while trying to contact the device hosting the requested function.
This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.
Parameters : callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the boolean result
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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datalogger
→
load() YDataLogger
Preloads the data logger cache with a specified validity duration.
js function load(
msValidity
) nodejs function load(
msValidity
) php function load(
$msValidity
) cpp m pas vb cs java py
YRETCODE load( int
msValidity
)
-(YRETCODE) load : (int)
msValidity
function load(
msValidity
: integer): YRETCODE function load( ByVal
msValidity
As Integer) As YRETCODE
YRETCODE load( int
msValidity
) int load( long
msValidity
) def load(
msValidity
)
By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance.
Parameters : msValidity
an integer corresponding to the validity attributed to the loaded function parameters, in milliseconds
Returns :
YAPI_SUCCESS when the call succeeds. On failure, throws an exception or returns a negative error code.
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datalogger
→
load_async() YDataLogger
Preloads the data logger cache with a specified validity duration (asynchronous version).
js function load_async(
msValidity
,
callback
,
context
) nodejs function load_async(
msValidity
,
callback
,
context
)
By default, whenever accessing a device, all function attributes are kept in cache for the standard duration (5 ms). This method can be used to temporarily mark the cache as valid for a longer period, in order to reduce network trafic for instance. This asynchronous version exists only in Javascript. It uses a callback instead of a return value in order to avoid blocking the Javascript virtual machine.
Parameters : msValidity
an integer corresponding to the validity of the loaded function parameters, in milliseconds
callback
callback function that is invoked when the result is known. The callback function receives three arguments: the caller-specific context object, the receiving function object and the error code
(or
YAPI_SUCCESS
)
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing : the result is provided to the callback.
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datalogger
→
nextDataLogger()
Continues the enumeration of data loggers started using yFirstDataLogger()
.
js nodejs function nextDataLogger( ) function nextDataLogger( ) php cpp function nextDataLogger( )
YDataLogger * nextDataLogger( ) m pas vb cs java py
-(YDataLogger*) nextDataLogger function nextDataLogger( ): TYDataLogger function nextDataLogger( ) As YDataLogger
YDataLogger nextDataLogger( )
YDataLogger nextDataLogger( ) def nextDataLogger( )
YDataLogger
Returns :
a pointer to a
YDataLogger
object, corresponding to a data logger currently online, or a null
pointer if there are no more data loggers to enumerate.
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datalogger
→
registerValueCallback()
Registers the callback function that is invoked on every change of advertised value.
js function registerValueCallback(
callback
) nodejs function registerValueCallback(
callback
) php function registerValueCallback(
$callback
) cpp m pas vb cs java py int registerValueCallback( YDataLoggerValueCallback
callback
)
-(int) registerValueCallback : (YDataLoggerValueCallback)
callback
function registerValueCallback(
callback
: TYDataLoggerValueCallback): LongInt function registerValueCallback( ) As Integer int registerValueCallback( ValueCallback
callback
) int registerValueCallback( UpdateCallback
callback
) def registerValueCallback(
callback
)
YDataLogger
The callback is invoked only during the execution of ySleep
or yHandleEvents
. This provides control over the time when the callback is triggered. For good responsiveness, remember to call one of these two functions periodically. To unregister a callback, pass a null pointer as argument.
Parameters : callback
the callback function to call, or a null pointer. The callback function should take two arguments: the function object of which the value has changed, and the character string describing the new advertised value.
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datalogger
→
set_autoStart() datalogger
→
setAutoStart()
Changes the default activation state of the data logger on power up.
js nodejs function set_autoStart(
newval
) function set_autoStart(
newval
) php cpp function set_autoStart(
$newval
) int set_autoStart( Y_AUTOSTART_enum
newval
) m pas vb cs
-(int) setAutoStart : (Y_AUTOSTART_enum)
newval
function set_autoStart(
newval
: Integer): integer function set_autoStart( ByVal
newval
As Integer) As Integer int set_autoStart( int
newval
) java py cmd int set_autoStart( int
newval
) def set_autoStart(
newval
)
YDataLogger
target
set_autoStart
newval
YDataLogger
Remember to call the saveToFlash()
method of the module if the modification must be kept.
Parameters : newval
either Y_AUTOSTART_OFF or Y_AUTOSTART_ON , according to the default activation state of the data logger on power up
Returns :
YAPI_SUCCESS
if the call succeeds.
On failure, throws an exception or returns a negative error code.
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datalogger
→
set_logicalName() datalogger
→
setLogicalName()
Changes the logical name of the data logger.
js function set_logicalName(
newval
) nodejs function set_logicalName(
newval
) php cpp m pas function set_logicalName(
$newval
) int set_logicalName( const string&
newval
)
-(int) setLogicalName : (NSString*)
newval
function set_logicalName(
newval
: string): integer vb cs java py cmd function set_logicalName( ByVal
newval
As String) As Integer int set_logicalName( string
newval
) int set_logicalName( String
newval
) def set_logicalName(
newval
)
YDataLogger
target
set_logicalName
newval
YDataLogger
You can use yCheckLogicalName()
prior to this call to make sure that your parameter is valid.
Remember to call the saveToFlash()
method of the module if the modification must be kept.
Parameters : newval
a string corresponding to the logical name of the data logger.
Returns :
YAPI_SUCCESS if the call succeeds. On failure, throws an exception or returns a negative error code.
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datalogger
→
set_recording() datalogger
→
setRecording()
Changes the activation state of the data logger to start/stop recording data.
js nodejs function set_recording(
newval
) function set_recording(
newval
) php cpp function set_recording(
$newval
) int set_recording( Y_RECORDING_enum
newval
) m pas vb cs
-(int) setRecording : (Y_RECORDING_enum)
newval
function set_recording(
newval
: Integer): integer function set_recording( ByVal
newval
As Integer) As Integer int set_recording( int
newval
) java py cmd int set_recording( int
newval
) def set_recording(
newval
)
YDataLogger
target
set_recording
newval
21. High-level API Reference
YDataLogger
Parameters : newval
either
Y_RECORDING_OFF
or
Y_RECORDING_ON
, according to the activation state of the data logger to start/stop recording data
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
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datalogger
→
set_timeUTC() datalogger
→
setTimeUTC()
Changes the current UTC time reference used for recorded data.
js function set_timeUTC(
newval
) nodejs function set_timeUTC(
newval
) php cpp m pas function set_timeUTC(
$newval
) int set_timeUTC( s64
newval
)
-(int) setTimeUTC : (s64)
newval
function set_timeUTC(
newval
: int64): integer vb cs java py cmd function set_timeUTC( ByVal
newval
As Long) As Integer int set_timeUTC( long
newval
) int set_timeUTC( long
newval
) def set_timeUTC(
newval
)
YDataLogger
target
set_timeUTC
newval
Parameters : newval
an integer corresponding to the current UTC time reference used for recorded data
Returns :
YAPI_SUCCESS if the call succeeds.
On failure, throws an exception or returns a negative error code.
YDataLogger
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datalogger
→
set_userData() datalogger
→
setUserData()
YDataLogger
Stores a user context provided as argument in the userData attribute of the function.
js nodejs function set_userData(
data
) function set_userData(
data
) php cpp function set_userData(
$data
) void set_userData( void*
data
) m pas vb cs java py
-(void) setUserData : (void*)
data
procedure set_userData(
data
: Tobject) procedure set_userData( ByVal
data
As Object) void set_userData( object
data
) void set_userData( Object
data
) def set_userData(
data
)
This attribute is never touched by the API, and is at disposal of the caller to store a context.
Parameters : data
any kind of object to be stored
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datalogger
→
wait_async() YDataLogger
Waits for all pending asynchronous commands on the module to complete, and invoke the userprovided callback function.
js function wait_async(
callback
,
context
) nodejs function wait_async(
callback
,
context
)
The callback function can therefore freely issue synchronous or asynchronous commands, without risking to block the Javascript VM.
Parameters : callback
callback function that is invoked when all pending commands on the module are completed. The callback function receives two arguments: the caller-specific context object and the receiving function object.
context
caller-specific object that is passed as-is to the callback function
Returns :
nothing.
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21.5. Recorded data sequence
YDataSet objects make it possible to retrieve a set of recorded measures for a given sensor and a specified time interval. They can be used to load data points with a progress report. When the
YDataSet object is instanciated by the get_recordedData()
function, no data is yet loaded from the module. It is only when the loadMore()
method is called over and over than data will be effectively loaded from the dataLogger.
A preview of available measures is available using the function get_preview()
as soon as loadMore() has been called once. Measures themselves are available using function get_measures()
when loaded by subsequent calls to loadMore()
.
This class can only be used on devices that use a recent firmware, as YDataSet objects are not supported by firmwares older than version 13000.
In order to use the functions described here, you should include: js nodejs php cpp m pas vb cs java py
<script type='text/javascript' src='yocto_api.js'></script> var yoctolib = require('yoctolib'); var YAPI = yoctolib.YAPI; var YModule = yoctolib.YModule; require_once('yocto_api.php');
#include "yocto_api.h"
#import "yocto_api.h" uses yocto_api; yocto_api.vb
yocto_api.cs
import com.yoctopuce.YoctoAPI.YModule; from yocto_api import *
YDataSet
methods
Returns the end time of the dataset, relative to the Jan 1, 1970.
Returns the hardware identifier of the function that performed the measure, without reference to the module.
Returns the unique hardware identifier of the function who performed the measures, in the form
SERIAL.FUNCTIONID
.
Returns all measured values currently available for this DataSet, as a list of YMeasure objects.
Returns a condensed version of the measures that can retrieved in this YDataSet, as a list of YMeasure objects.
Returns the progress of the downloads of the measures from the data logger, on a scale from 0 to 100.
Returns the start time of the dataset, relative to the Jan 1, 1970.
Returns an YMeasure object which summarizes the whole DataSet.
Returns the measuring unit for the measured value.
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Loads the the next block of measures from the dataLogger, and updates the progress indicator.
callback
,
context
)
Loads the the next block of measures from the dataLogger asynchronously.
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dataset
→
get_endTimeUTC() dataset
→
endTimeUTC()
Returns the end time of the dataset, relative to the Jan 1, 1970.
js nodejs function get_endTimeUTC( ) function get_endTimeUTC( ) php cpp function get_endTimeUTC( ) s64 get_endTimeUTC( ) m pas vb cs java py
-(s64) endTimeUTC function get_endTimeUTC( ): int64 function get_endTimeUTC( ) As Long long get_endTimeUTC( ) long get_endTimeUTC( ) def get_endTimeUTC( )
YDataSet
When the YDataSet is created, the end time is the value passed in parameter to the get_dataSet() function. After the very first call to loadMore()
, the end time is updated to reflect the timestamp of the last measure actually found in the dataLogger within the specified range.
Returns :
an unsigned number corresponding to the number of seconds between the Jan 1, 1970 and the end of this data set (i.e. Unix time representation of the absolute time).
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dataset
→
get_functionId() dataset
→
functionId()
YDataSet
Returns the hardware identifier of the function that performed the measure, without reference to the module.
js function get_functionId( ) nodejs function get_functionId( ) php cpp m pas function get_functionId( ) string get_functionId( )
-(NSString*) functionId function get_functionId( ): string vb cs java py function get_functionId( ) As String string get_functionId( )
String get_functionId( ) def get_functionId( )
For example temperature1
.
Returns :
a string that identifies the function (ex: temperature1
)
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dataset
→
get_hardwareId() dataset
→
hardwareId()
YDataSet
Returns the unique hardware identifier of the function who performed the measures, in the form
SERIAL.FUNCTIONID
.
js function get_hardwareId( ) nodejs function get_hardwareId( ) php function get_hardwareId( ) cpp m pas vb cs java py string get_hardwareId( )
-(NSString*) hardwareId function get_hardwareId( ): string function get_hardwareId( ) As String string get_hardwareId( )
String get_hardwareId( ) def get_hardwareId( )
The unique hardware identifier is composed of the device serial number and of the hardware identifier of the function (for example
THRMCPL1-123456.temperature1
)
Returns :
a string that uniquely identifies the function (ex: THRMCPL1-123456.temperature1
)
On failure, throws an exception or returns Y_HARDWAREID_INVALID .
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dataset
→
get_measures() dataset
→
measures()
YDataSet
Returns all measured values currently available for this DataSet, as a list of YMeasure objects.
js function get_measures( ) nodejs function get_measures( ) php cpp m pas function get_measures( ) vector<YMeasure> get_measures( )
-(NSMutableArray*) measures function get_measures( ): TYMeasureArray vb cs java py function get_measures( ) As List
List<YMeasure> get_measures( )
ArrayList<YMeasure> get_measures( ) def get_measures( )
Each item includes: - the start of the measure time interval - the end of the measure time interval - the minimal value observed during the time interval - the average value observed during the time interval the maximal value observed during the time interval
Before calling this method, you should call loadMore()
to load data from the device. You may have to call loadMore() several time until all rows are loaded, but you can start looking at available data rows before the load is complete.
The oldest measures are always loaded first, and the most recent measures will be loaded last. As a result, timestamps are normally sorted in ascending order within the measure table, unless there was an unexpected adjustment of the datalogger UTC clock.
Returns :
a table of records, where each record depicts the measured value for a given time interval
On failure, throws an exception or returns an empty array.
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dataset
→
get_preview() dataset
→
preview()
YDataSet
Returns a condensed version of the measures that can retrieved in this YDataSet, as a list of
YMeasure objects.
js nodejs function get_preview( ) function get_preview( ) php cpp function get_preview( ) vector<YMeasure> get_preview( ) m pas vb cs java py
-(NSMutableArray*) preview function get_preview( ): TYMeasureArray function get_preview( ) As List
List<YMeasure> get_preview( )
ArrayList<YMeasure> get_preview( ) def get_preview( )
Each item includes: - the start of a time interval - the end of a time interval - the minimal value observed during the time interval - the average value observed during the time interval - the maximal value observed during the time interval
This preview is available as soon as loadMore()
has been called for the first time.
Returns :
a table of records, where each record depicts the measured values during a time interval
On failure, throws an exception or returns an empty array.
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dataset
→
get_progress() dataset
→
progress()
YDataSet
Returns the progress of the downloads of the measures from the data logger, on a scale from 0 to
100.
js function get_progress( ) nodejs function get_progress( ) php cpp m pas function get_progress( ) int get_progress( )
-(int) progress function get_progress( ): LongInt vb cs java py function get_progress( ) As Integer int get_progress( ) int get_progress( ) def get_progress( )
When the object is instanciated by get_dataSet
, the progress is zero. Each time loadMore()
is invoked, the progress is updated, to reach the value 100 only once all measures have been loaded.
Returns :
an integer in the range 0 to 100 (percentage of completion).
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dataset
→
get_startTimeUTC() dataset
→
startTimeUTC()
YDataSet
Returns the start time of the dataset, relative to the Jan 1, 1970.
js nodejs function get_startTimeUTC( ) function get_startTimeUTC( ) php cpp function get_startTimeUTC( ) s64 get_startTimeUTC( ) m pas vb cs java py
-(s64) startTimeUTC function get_startTimeUTC( ): int64 function get_startTimeUTC( ) As Long long get_startTimeUTC( ) long get_startTimeUTC( ) def get_startTimeUTC( )
When the YDataSet is created, the start time is the value passed in parameter to the get_dataSet()
function. After the very first call to loadMore()
, the start time is updated to reflect the timestamp of the first measure actually found in the dataLogger within the specified range.
Returns :
an unsigned number corresponding to the number of seconds between the Jan 1, 1970 and the beginning of this data set (i.e. Unix time representation of the absolute time).
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dataset
→
get_summary() dataset
→
summary()
YDataSet
Returns an YMeasure object which summarizes the whole DataSet.
js function get_summary( ) nodejs function get_summary( ) php cpp m pas function get_summary( )
YMeasure get_summary( )
-(YMeasure*) summary function get_summary( ): TYMeasure vb cs java py function get_summary( ) As YMeasure
YMeasure get_summary( )
YMeasure get_summary( ) def get_summary( )
In includes the following information: - the start of a time interval - the end of a time interval - the minimal value observed during the time interval - the average value observed during the time interval the maximal value observed during the time interval
This summary is available as soon as loadMore()
has been called for the first time.
Returns :
an YMeasure object
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dataset
→
get_unit() dataset
→
unit()
Returns the measuring unit for the measured value.
js nodejs function get_unit( ) function get_unit( ) php cpp function get_unit( ) string get_unit( ) m pas vb cs java py
-(NSString*) unit function get_unit( ): string function get_unit( ) As String string get_unit( )
String get_unit( ) def get_unit( )
Returns :
a string that represents a physical unit.
On failure, throws an exception or returns
Y_UNIT_INVALID
.
21. High-level API Reference
YDataSet
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dataset
→
loadMore() YDataSet
Loads the the next block of measures from the dataLogger, and updates the progress indicator.
js function loadMore( ) nodejs function loadMore( ) php function loadMore( ) cpp m pas vb cs java py int loadMore( )
-(int) loadMore function loadMore( ): LongInt function loadMore( ) As Integer int loadMore( ) int loadMore( ) def loadMore( )
Returns :
an integer in the range 0 to 100 (percentage of completion), or a negative error code in case of failure.
On failure, throws an exception or returns a negative error code.
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dataset
→
loadMore_async()
Loads the the next block of measures from the dataLogger asynchronously.
js function loadMore_async(
callback
,
context
) nodejs function loadMore_async(
callback
,
context
)
21. High-level API Reference
YDataSet
Parameters : callback
callback function that is invoked when the w The callback function receives three arguments: the user-specific context object - the YDataSet object whose loadMore_async was invoked - the load result: either the progress indicator (0...100), or a negative error code in case of failure.
context
user-specific object that is passed as-is to the callback function
Returns :
nothing.
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21. High-level API Reference
21.6. Measured value
YMeasure objects are used within the API to represent a value measured at a specified time. These objects are used in particular in conjunction with the YDataSet class.
In order to use the functions described here, you should include: js nodejs php cpp
<script type='text/javascript' src='yocto_api.js'></script> var yoctolib = require('yoctolib'); var YAPI = yoctolib.YAPI; var YModule = yoctolib.YModule; require_once('yocto_api.php');
#include "yocto_api.h" m pas vb cs java py
#import "yocto_api.h" uses yocto_api; yocto_api.vb
yocto_api.cs
import com.yoctopuce.YoctoAPI.YModule; from yocto_api import *
YMeasure
methods
Returns the average value observed during the time interval covered by this measure.
Returns the end time of the measure, relative to the Jan 1, 1970 UTC (Unix timestamp).
Returns the largest value observed during the time interval covered by this measure.
Returns the smallest value observed during the time interval covered by this measure.
Returns the start time of the measure, relative to the Jan 1, 1970 UTC (Unix timestamp).
286 www.yoctopuce.com
21. High-level API Reference
measure
→
get_averageValue() measure
→
averageValue()
Returns the average value observed during the time interval covered by this measure.
js nodejs function get_averageValue( ) function get_averageValue( ) php cpp function get_averageValue( ) double get_averageValue( ) m pas vb cs java py
-(double) averageValue function get_averageValue( ): double function get_averageValue( ) As Double double get_averageValue( ) double get_averageValue( ) def get_averageValue( )
YMeasure
Returns :
a floating-point number corresponding to the average value observed.
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21. High-level API Reference
measure
→
get_endTimeUTC() measure
→
endTimeUTC()
YMeasure
Returns the end time of the measure, relative to the Jan 1, 1970 UTC (Unix timestamp).
js function get_endTimeUTC( ) nodejs function get_endTimeUTC( ) php cpp m pas function get_endTimeUTC( ) double get_endTimeUTC( )
-(double) endTimeUTC function get_endTimeUTC( ): double vb cs java py function get_endTimeUTC( ) As Double double get_endTimeUTC( ) double get_endTimeUTC( ) def get_endTimeUTC( )
When the recording rate is higher then 1 sample per second, the timestamp may have a fractional part.
Returns :
an floating point number corresponding to the number of seconds between the Jan 1, 1970 UTC and the end of this measure.
288 www.yoctopuce.com
21. High-level API Reference
measure
→
get_maxValue() measure
→
maxValue()
Returns the largest value observed during the time interval covered by this measure.
js nodejs function get_maxValue( ) function get_maxValue( ) php cpp function get_maxValue( ) double get_maxValue( ) m pas vb cs java py
-(double) maxValue function get_maxValue( ): double function get_maxValue( ) As Double double get_maxValue( ) double get_maxValue( ) def get_maxValue( )
YMeasure
Returns :
a floating-point number corresponding to the largest value observed.
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21. High-level API Reference
measure
→
get_minValue() measure
→
minValue()
Returns the smallest value observed during the time interval covered by this measure.
js function get_minValue( ) nodejs function get_minValue( ) php cpp m pas function get_minValue( ) double get_minValue( )
-(double) minValue function get_minValue( ): double vb cs java py function get_minValue( ) As Double double get_minValue( ) double get_minValue( ) def get_minValue( )
YMeasure
Returns :
a floating-point number corresponding to the smallest value observed.
290 www.yoctopuce.com
21. High-level API Reference
measure
→
get_startTimeUTC() measure
→
startTimeUTC()
YMeasure
Returns the start time of the measure, relative to the Jan 1, 1970 UTC (Unix timestamp).
js nodejs function get_startTimeUTC( ) function get_startTimeUTC( ) php cpp function get_startTimeUTC( ) double get_startTimeUTC( ) m pas vb cs java py
-(double) startTimeUTC function get_startTimeUTC( ): double function get_startTimeUTC( ) As Double double get_startTimeUTC( ) double get_startTimeUTC( ) def get_startTimeUTC( )
When the recording rate is higher then 1 sample per second, the timestamp may have a fractional part.
Returns :
an floating point number corresponding to the number of seconds between the Jan 1, 1970 UTC and the beginning of this measure.
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22. Troubleshooting
22.1. Linux and USB
To work correctly under Linux, the the library needs to have write access to all the Yoctopuce USB peripherals. However, by default under Linux, USB privileges of the non-root users are limited to read access. To avoid having to run the VirtualHub as root, you need to create a new udev rule to authorize one or several users to have write access to the Yoctopuce peripherals.
To add a new udev rule to your installation, you must add a file with a name following the "
##arbitraryName.rules
" format, in the "
/etc/udev/rules.d
" directory. When the system is starting, udev reads all the files with a "
.rules
" extension in this directory, respecting the alphabetical order (for example, the "
51-custom.rules
" file is interpreted AFTER the "
50udev-default.rules
" file).
The "
50-udev-default
" file contains the system default udev rules. To modify the default behavior, you therefore need to create a file with a name that starts with a number larger than 50, that will override the system default rules. Note that to add a rule, you need a root access on the system.
In the udev_conf
directory of the VirtualHub for Linux
1
archive, there are two rule examples which you can use as a basis.
Example 1: 51-yoctopuce.rules
This rule provides all the users with read and write access to the Yoctopuce USB peripherals. Access rights for all other peripherals are not modified. If this scenario suits you, you only need to copy the
"
51-yoctopuce_all.rules
" file into the "
/etc/udev/rules.d
" directory and to restart your system.
# udev rules to allow write access to all users
# for Yoctopuce USB devices
SUBSYSTEM=="usb", ATTR{idVendor}=="24e0", MODE="0666"
Example 2: 51-yoctopuce_group.rules
This rule authorizes the "yoctogroup" group to have read and write access to Yoctopuce USB peripherals. Access rights for all other peripherals are not modified. If this scenario suits you, you
1 http://www.yoctopuce.com/FR/virtualhub.php
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293
22. Troubleshooting
only need to copy the "
51-yoctopuce_group.rules
" file into the "
/etc/udev/rules.d
" directory and restart your system.
# udev rules to allow write access to all users of "yoctogroup"
# for Yoctopuce USB devices
SUBSYSTEM=="usb", ATTR{idVendor}=="24e0", MODE="0664", GROUP="yoctogroup"
22.2. ARM Platforms: HF and EL
There are two main flavors of executable on ARM: HF (Hard Float) binaries, and EL (EABI Little
Endian) binaries. These two families are not compatible at all. The compatibility of a given ARM platform with of one of these two families depends on the hardware and on the OS build. ArmHL and
ArmEL compatibility problems are quite difficult to detect. Most of the time, the OS itself is unable to make a difference between an HF and an EL executable and will return meaningless messages when you try to use the wrong type of binary.
All pre-compiled Yoctopuce binaries are provided in both formats, as two separate ArmHF et ArmEL executables. If you do not know what family your ARM platform belongs to, just try one executable from each family.
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23. Characteristics
You can find below a summary of the main technical characteristics of your Yocto-Amp module.
Width
Length
Weight
USB connector
Max Current (continuous)
Max Current (peak)
Refresh rate
Accuracy (AC)
Accuracy (DC)
Sensitivity
Supported Operating Systems
Drivers
API / SDK / Libraries (USB+TCP)
API / SDK / Libraries (TCP only)
RoHS
USB Vendor ID
USB Device ID
Suggested enclosure
20 mm
56 mm
8 g micro-B
10 A
17 A
10 Hz (DC)
5 mA, 3 %
2 mA, 1 %
2 mA, 0.3%
Windows, Linux (Intel + ARM), Mac OS X, Android no driver needed
C++, Objective-C, C#, VB .NET, Delphi, Python, Java/Android
Javascript, Node.js, PHP, Java yes
0x24E0
0x001F
YoctoBox-Long-Thick-Black-Vents
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23. Characteristics
296 www.yoctopuce.com
Index
A
B
C
calibrateFromPoints, YCurrent 199
Current 9, 22, 30, 33, 41, 51, 59, 66, 72, 79, 85,
D
E
Error 38, 49, 56, 63, 70, 76, 83, 89, 95, 107
F
FindDataLogger, YDataLogger 239
FirstDataLogger, YDataLogger 240
forgetAllDataStreams, YDataLogger 242
G
get_advertisedValue, YCurrent 201
get_advertisedValue, YDataLogger 243
get_autoStart, YDataLogger 244
get_averageValue, YMeasure 286
get_currentRawValue, YCurrent 202
get_currentRunIndex, YDataLogger 245
get_currentValue, YCurrent 203
get_dataStreams, YDataLogger 247
get_errorMessage, YCurrent 204
get_errorMessage, YDataLogger 248
get_errorType, YDataLogger 249
get_firmwareRelease, YModule 163
get_friendlyName, YCurrent 206
get_friendlyName, YDataLogger 250
get_functionDescriptor, YCurrent 207
get_functionDescriptor, YDataLogger 251
get_functionId, YDataLogger 252
get_hardwareId, YDataLogger 253
get_highestValue, YCurrent 210
get_logFrequency, YCurrent 211
get_logicalName, YDataLogger 254
get_module_async, YCurrent 215
get_module_async, YDataLogger 256
get_persistentSettings, YModule 169
get_productRelease, YModule 172
get_rebootCountdown, YModule 173
get_recordedData, YCurrent 216
get_recording, YDataLogger 257
get_reportFrequency, YCurrent 217
get_startTimeUTC, YDataSet 280
get_startTimeUTC, YMeasure 290
H
I
isOnline_async, YDataLogger 261
J
L
loadCalibrationPoints, YCurrent 224
M
Module 11, 20, 21, 30, 35, 43, 53, 61, 68, 74, 81,
N
nextDataLogger, YDataLogger 264
O
P
R
RegisterDeviceArrivalCallback, YAPI 137
RegisterDeviceRemovalCallback, YAPI 138
RegisterHubDiscoveryCallback, YAPI 140
registerTimedReportCallback, YCurrent 227
registerValueCallback, YCurrent 228
registerValueCallback, YDataLogger 265
S
set_autoStart, YDataLogger 266
set_highestValue, YCurrent 229
set_logFrequency, YCurrent 230
set_logicalName, YDataLogger 267
set_recording, YDataLogger 268
set_reportFrequency, YCurrent 233
T
triggerFirmwareUpdate, YModule 192
U
UpdateDeviceList_async, YAPI 148
V
W
Y
YAPI 127-148 yCheckLogicalName 127
Yocto-Amp 20, 29, 33, 41, 51, 59, 65, 71, 79, 85,
yRegisterDeviceArrivalCallback 137
yRegisterDeviceRemovalCallback 138
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