6, Using the 1769-SDN Scanner Module with CompactLogix Controllers. Allen-Bradley 1769-SDN
Allen-Bradley 1769-SDN is a DeviceNet Scanner Module that provides a gateway between CompactLogix controllers and DeviceNet devices. It allows you to connect up to 64 DeviceNet slave devices and communicate with them using the RSNetWorx for DeviceNet software. The 1769-SDN is ideal for applications where you need to control a large number of devices, such as in a manufacturing or automation setting.
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System Diagram
Chapter
6
Using the 1769-SDN Scanner Module with
CompactLogix Controllers
This chapter contains an example where the 1769-SDN scanner module is used with a 1769-L30 controller and a 1769-ADN adapter module.
The following table describes what this chapter contains and where to find specific information.
For information about
Configuring The DeviceNet System using RSNetWorx
Creating a Project for the 1769-L30 CompactLogix Controller
See page
The following system diagram shows the example DeviceNet network.
Figure 6.1 1769-SDN DeviceNet Scanner System with a 1769-ADN Adapter
1
Notebook Computer with:
•
RSLogix 5000, Version 8.02 or higher
•
RSNetWorx, Version 3.00 or higher
•
RSLinx, Version 2.30 or higher
• 1784-PCID DeviceNet Interface card (or a 1770-KFD and a comm. Port)
DeviceNet
MS
IO
NS
DIAG
DeviceNet
Power Supply
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6-2 Using the 1769-SDN Scanner Module with CompactLogix Controllers
Purpose
This example shows how to provide DeviceNet connectivity for
Distributed I/O for CompactLogix controllers.
Scope
This example describes:
• using RSNetWorx for DeviceNet to assign node addresses to the
1769-SDN and the 1769-ADN and map the adapter’s image into the scanner
• creating a CompactLogix project including the necessary configuration for the 1769-SDN DeviceNet scanner module
• controlling outputs and reading inputs with the distributed I/O via DeviceNet
Configuring The DeviceNet
System using RSNetWorx
The following procedures describe how to assign the node addresses and map the adapter’s image to the scanner.
Configuring the 1769-ADN Adapter
1.
Connect the 1769-SDN scanner, 1769-ADN adapter, and the computer together on a DeviceNet network as shown in the
System Diagram.
2.
Start RSNetWorx. The following screen appears:
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Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-3
3.
Click the Network pull-down menu and select Online (or click the Online icon). The RSLinx communication driver screen appears.
Choose the “1784-PCD-1, DeviceNet” driver, or if you are using a
1770-KFD, choose its driver. In this example, it is assumed that one of these drivers has been previously configured in RSLinx.
4.
The software then prompts you to either upload or download.
Choose upload .
RSNetWorx then browses your network for valid devices. The online screen should look like the following, where the
1784-PCID card (computer) is node 6, the 1769-ADN is node 15, and the 1769-SDN is node 32 for this example.
See Node Commissioning on page 4-7 if you need to add
devices to the DeviceNet network.
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6-4 Using the 1769-SDN Scanner Module with CompactLogix Controllers
5.
Right click on the 1769-ADN and choose Properties . The following screen appears:
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6.
Click on the I/O Bank 1 Configuration tab, then choose upload when prompted. The actual 1769-ADN I/O layout appears. From this screen you can configure the I/O modules in the 1769-ADN system by simply clicking on the slot number box associated with each I/O module.
For this example, only the two analog modules need to be configured. The graphical user interface makes configuring these modules very straight forward. Refer to the Compact I/O Analog
Modules User Manual , publication 1769-UM002A-EN-P for additional information concerning the analog modules.
TIP
Only analog and specialty modules are configurable. Discrete I/O modules, power supplies, and end caps are not configurable.
Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-5
7.
When the I/O modules are configured, click on the Summary tab. Note the number of bytes of input and output data. This will be used later when adding the adapter to the 1769-SDN’s scanlist.
Click Apply , then OK to save the configuration and download it to the adapter.
TIP
Configuration changes made to the adapter or any of its I/O modules with RSNetWorx will not be saved or downloaded to the adapter once the adapter is configured in a scanner’s scanlist.
To make configuration changes, the controller must be placed into the Program mode and the adapter must be temporarily removed from the scanner’s scanlist.
Setting Up the 1769-SDN Scanlist
Next, add the adapter to the scanner’s scanlist.
1.
Right click on the 1769-SDN and choose Properties . The following screen appears:
2.
Click the Scanlist tab, then click Upload when prompted. The area on the left is called “Available Devices” and the area on the right is called “Scanlist”. The 1769-ADN adapter should be on the left. Allen-Bradley Drives
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6-6 Using the 1769-SDN Scanner Module with CompactLogix Controllers
3.
Click on the adapter , then click on the single arrow pointing to the right. This moves the adapter from Available Devices to the scanner’s scanlist.
4.
Then, click on the Edit I/O Parameters button and the following screen appears:
5.
Verify that the Rx Size and Tx Size are correct. The Tx
(Transmit) and Rx (Receive) sizes correspond to the total number of output and input bytes noted from the adapter’s
summary page (step 7 on page 6-5).
In this example, the scanner transmits 6 bytes to the adapter
(output data) and receives 28 bytes from the adapter (input data). Click OK when finished with this screen.
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Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-7
6.
Click on the Input tab. The following screen appears:
The first 66 words (0 to 65) are read-only. Refer to page 5-2 in
this manual for information concerning these status words. For this example, 28 bytes or 14 words of input data will be mapped by the scanner to the 1769-L30 controller’s input tag, beginning with word 66. The 1769-ADN adapter also adds 2 words of status information to the input data. Therefore, the actual input data from the I/O modules in the 1769-ADN adapter’s system begins at word 68.
Click Apply , then OK .
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6-8 Using the 1769-SDN Scanner Module with CompactLogix Controllers
7.
Click on the Output tab. The following screen appears:
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The first 2 words (0 and 1) are read-only from the scanner’s point of view, but are control words for the controller. Bit 0 of output word 0 is used for control. It is the scanner’s Run bit.
When set (1), it places the scanner into Run mode. When the scanner’s Run bit is a 0, the scanner is in Idle mode even if the controller is in Run mode.
See also: Module Command Array on page 5-8.
The output data begins with word 2. This is where the actual output data goes for the output modules in the 1769-ADN adapter’s system.
TIP
The input and output data being exchanged by the scanner and adapter is packed data. This means that there is no special structure to it that makes it obvious which I/O module it is associated with.
To establish which data is from which module, you must list the number of input and output words each module has. Then, based on its position in the I/O bank, you can determine where any module’s data is in the controller’s
I/O tags.
Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-9
For example, there are 28 bytes of input data and 6 bytes of output data for this example. The I/O modules in the adapter’s system are:
Table 6.1 1769-ADN I/O Bank Input and Output Data Size
Module
ADN Status Information
(added by the 1769-ADN)
1769-IA16
1769-OB16
1769-IF4
1769-OF2
Total Words
Total Bytes
Input
2 words
1 word
1 word
6 words
4 words
14 words
28 bytes
Output
0 words
0 words
1 word
0 words
2 words
3 words
6 bytes
The total is 14 input words or 28 input bytes. The first two input words are adapter status, leaving 12 words (24 bytes) for data. In this example, words 66 and 67 are the two words of status in the controller input tag for the scanner. The actual input data is then mapped to the controller’s input data tag at the following word locations:
Table 6.2 Input Data Tag
Location
Words 66 and 67
Word 68
Word 69
Words 70 to 75
Words 76 to 79
Description
1769-ADN Status Information
1769-IA16 module’s input word
1769-OB16 module’s input data (output data echo)
1769-IF4 module’s input data
1769-OF2 module’s input data
The output data can be determined in a similar manner. This data begins with word 2 of the output tag in the controller for the scanner as follows:
Table 6.3 Output Data Tag
Location
Word 0 and 1
Word 2
Words 3 and 4
Description
See Module Command Array on page 5-8.
1769-OB16 module’s output word
1769-OF2 module’s output words
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6-10 Using the 1769-SDN Scanner Module with CompactLogix Controllers
Creating a Project for the
1769-L30 CompactLogix
Controller
Now create a 1769-L30 Project using RSLogix 5000. In this project you will configure the local I/O modules, including the scanner, and view the I/O tags created for scanner. Then you will create a simple ladder program to test our communications with the distributed I/O.
Double-click the RSLogix 5000 icon on your Desktop to start the software. The following screen appears:
Click on the File pull down menu and select New , or click the New icon. In the New Controller screen that appears, select the 1769-L30
CompactLogix5330 controller for the Type, then enter a name for this project. Click OK and the following screen appears:
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Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-11
The first thing to do is to configure the local I/O. The area on the left side of the screen is called the controller organizer. This is where you access controller properties, tasks, tags and configure I/O.
Right click on the last entry in the controller organizer called
CompactBus Local and choose New Module . The following screen appears:
From this screen you can choose, by catalog number, the two discrete
I/O modules in the local system. Select the 1769-IQ16 first, by single clicking on it and then click OK . The next screen that appears needs a name for the module. All other entries should be left at their default values, except keying which may be changed to one of the other two choices if desired. Compatible Module is the default. Click Finish , then repeat this procedure for the 1769-OV16.
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6-12 Using the 1769-SDN Scanner Module with CompactLogix Controllers
The scanner does not yet have a profile so you must use the Generic
Profile to configure it. After you right click on the CompactBus Local and choose New Module , click on the Generic 1769 Module , then click OK . The following screen appears:
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From the Generic Profile screen, enter a name for the scanner and choose Data – INT for the Comm Format. Then enter the following for the number of input , output and configuration words:
Table 6.4 Comm Format Data
Data
Input
Output
Config
Assembly Instance
101
100
102
5
0
Size
80
TIP
To learn how the Input and Output sizes are
calculated, see Calculating Maximum I/O Sizes for the 1769-SDN Scanner Module on page 6-15.
Once all values are entered, click Finish . The I/O modules should now all appear below the CompactBus Local in the controller organizer.
Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-13
All tags for I/O modules are automatically created when the profiles for these modules are configured. Double click on Controller Tags in the controller organizer to view these tags. Each I/O module slot has
Input, Output and Configuration tags created, if they apply. These
Local I/O tags are structured as follows:
Table 6.5 Local I/O Tag Structure
Tag
Local:s:I
Local:s:O
Local:s:C
Definition s is the slot number
I represents Input Data
O represents Output Data
C represents Configuration Data
Each of these tags can be further expanded by clicking the plus sign to the left of its entry. For example, click the [+] to the left of Local:3:I and the following tags appear:
Local:3:I.Fault
Local:3:I.Data
The Fault tag is a DINT, so clicking its plus sign only reveals its 32 bits. This is status information concerning the module’s connection to the CompactLogix controller. Clicking the plus sign to the left of the
Data tag reveals the 80 input words created when this value was entered into the Generic profile for the scanner. For this example, the input addresses for the scanner are broken down as follows:
Table 6.6 1769-SDN Input Addresses
Tag
Local:3:I.Data[0] through Local:3:I.Data[65]
Local:3:I.Data[66] through Local:3:I.Data[67]
Local:3:I.Data[68]
Local:3:I.Data[69]
Local:3:I.Data[70] through Local:3:I.Data[75]
Local:3:I.Data[76] through Local:3:I.Data[79]
Definition
Read Only Status
1769-ADN Status Information
Input Data from 1769-IA16
Input (output echo) Data from 1769-OB16
Input Data from 1769-IF4
Input Data from 1769-OF2
The Output tag created for the scanner is as follows:
Local:3:O
Click the [+] to its left to reveal Local:3:O.Data.
Click the [+] to its left and the 5 words of output data created when you created the Generic profile for the scanner will be displayed. This output data is broken down as follows for this example:
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6-14 Using the 1769-SDN Scanner Module with CompactLogix Controllers
Table 6.7 1769-SDN Output Addresses
Tag
Local:3:O.Data[0] through Local:3:O.Data[1]
Local:3:O.Data[2]
Local:3:O.Data[3] through Local:3:O.Data[4]
Definition
Control to 1769-SDN
(1)
Output data for 1769-OB16
Output data for 1769-OF2
(1)
Bit 0 of output word 0 is the Run mode bit for the scanner. With the controller in Run mode, set this bit to a 1 to place the scanner into the Run mode. With the controller in Run and this bit a 0, the scanner will be in Idle
mode and will not scan I/O. The Module Command Array is described in more detail on page 5-8.
Now that you have created a Project, configured the I/O and determined the location in the I/O tags where all input and output data resides, you can write the application program. The program for this example consists of a single rung that is used to place the scanner into the RUN mode.
To place the scanner in the Run mode when the CompactLogix controller is in the Run mode, either set “SDN_RUN” to a 1, or remove it from the program. When “SDN_RUN” is removed, the scanner’s Run bit is always in Run when the controller is in Run.
The rung appears as shown below:
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Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-15
You may add your own logic to the program and wire some I/O to test the I/O in the 1769-ADN adapter, or you may simply turn on outputs in the scanner’s output tags in the controller to verify that they physically turn on at the output card. In addition, you may wire an analog output to an analog input to verify the operation of the network and the analog modules. Be sure the analog modules are properly configured for such operation.
When your program is written, verify and save it, then download it to your controller to run and test your system.
Calculating Maximum I/O
Sizes for the 1769-SDN
Scanner Module
The calculations in this section apply to all Series A CompactLogix controllers, firmware revision 10 and earlier.
The amount of I/O a CompactLogix version 8 controller can exchange with Compact I/O modules is 256 16-bit words. In addition to the I/O words, the following items must be accounted for in the calculations:
•
4 words must be allotted for end cap checking
•
30 words must be allowed for system overhead requirements
TIP
If any module in a CompactLogix system requires more than 30 words for its configuration file, then that length should be used for the system overhead value.
There are two types of I/O modules in a CompactLogix system:
•
Modules with only input data
•
Modules with both input and output data
Modules with only input data are typically discrete input modules like the 1769-IQ16 and 1769-IA16. Discrete output modules, analog modules, and specialty modules contain both input and output images.
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6-16 Using the 1769-SDN Scanner Module with CompactLogix Controllers
Calculating I/O Usage for the I/O Modules
The formulas below are used to calculate the amount of I/O used by each type of I/O module. The amount of I/O used by each module will then be subtracted from the total amount of I/O supported by the
CompactLogix controller. If we calculate the amount of I/O used by each I/O module in the CompactLogix system, except for the scanner, then what remains is the maximum amount of I/O the scanner can support in that particular system.
Formula for Modules with Only Input Data
The formula is:
6 words + the number of input words rounded to the next even number
Formula for Modules with Input and Output Data
The formula is:
8 words + the number of input words rounded to the next even number + the number of output words rounded to the next even number
Example Calculations
These examples show how to determine the amount of data that will be left for the scanner module.
Example 1:
The 1769-IQ16 module contains only input data, so its total I/O count is:
6 words + 2 words = 8 total words of I/O
Since this module has only one input word, we must round up to 2.
Example 2:
The 1769-OV16 module contains one input and one output word, so its total I/O count is:
8 words + 2 words + 2 words = 12 total I/O words
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Using the 1769-SDN Scanner Module with CompactLogix Controllers 6-17
To determine how much I/O remains for the scanner module we must subtract the I/O used by the other I/O modules in the system, along with the system overhead and end cap detection from the total I/O supported by the CompactLogix controllers (256 words) as follows:
Table 6.8 I/O Data used by the 1769-IQ16 and 1769-OV16 Modules
I/O Words
256
-30
-4
-8
-12
202
Description total I/O words supported by CompactLogix controllers system overhead end cap detection
1769-IQ16 total I/O
1769-OV16 total I/O remaining I/O words
Calculating Remaining I/O Usage for the Scanner Modules
Now we must calculate the number of actual I/O left in the system for the scanner. The 1769-SDN scanner is the type of module with both input and output words.
The amount of I/O words left for the scanner is then calculated as follows:
8 words + N words = 202, where N = total number of input and output words for the for the scanner
N = 202 – 8 = 194 words
This means that in the Generic Profile for the 1769-SDN scanner module, up to a total of 194 words can be used, in any even number mix, with one limitation:
66 words are needed in the input image for Status information from the scanner and 2 words are needed in the output image for the Module Command Array.
This leaves 194 – 68 = 126 words left for actual I/O.
These 66 input words and 2 output words do need to be included in the total input and output words entered into the generic profile for the scanner.
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6-18 Using the 1769-SDN Scanner Module with CompactLogix Controllers
For this example, a total of 14 input words are needed to map the I/O in the 1769-ADN system back to the CompactLogix controller via the
1769-SDN. This must then be added to the 66 status words to calculate the number of input words to enter into the Generic Profile for the
scanner, as shown in Table 6.4. Also, we must add the 3 output words
to the 2 Module Command Array words and include this in the
Generic Profile for the scanner as well.
As shown in Table 6.4 on page 6-12, the total number of input words
for the Generic profile for this example is 80 and the total number of output words for the generic Profile for this example is 5.
The total I/O words used by the scanner for this example is then:
8 words + 80 words + 6 words = 94.
This is obviously less than the 194 words of unused I/O remaining after the 1769-IQ16 and 1769-OV16 modules’ I/O totals were subtracted from the CompactLogix controller’s I/O capacity. This application will not exceed the amount of I/O the CompactLogix controller can access.
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Key features
- Connects up to 64 DeviceNet slave devices
- Provides a gateway between CompactLogix controllers and DeviceNet devices
- Uses the RSNetWorx for DeviceNet software for configuration
- Supports both explicit and implicit messaging
- Provides diagnostic information for troubleshooting
- Has a built-in watchdog timer to ensure reliable operation