USB-1208FS-Plus-OEM - Measurement Computing
USB-1208FS-Plus-OEM
Analog and Digital I/O
User's Guide
Document Revision 2A
January 2015
© Copyright 2015
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either trademarks or registered trademarks of Measurement Computing Corporation. Refer to the Copyrights &
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photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
Notice
Measurement Computing Corporation does not authorize any Measurement Computing Corporation product for
use in life support systems and/or devices without prior written consent from Measurement Computing
Corporation. Life support devices/systems are devices or systems that, a) are intended for surgical implantation
into the body, or b) support or sustain life and whose failure to perform can be reasonably expected to result in
injury. Measurement Computing Corporation products are not designed with the components required, and are
not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis of
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HM USB-1208FS-Plus-OEM
Table of Contents
Preface
About this User's Guide ....................................................................................................................... 5
What you will learn from this user's guide ......................................................................................................... 5
Conventions in this user's guide ......................................................................................................................... 5
Where to find more information ......................................................................................................................... 5
Chapter 1
Introducing the USB-1208FS-Plus-OEM ............................................................................................. 6
Functional block diagram ................................................................................................................................... 6
Chapter 2
Installing the USB-1208FS-Plus-OEM ................................................................................................. 7
Unpacking........................................................................................................................................................... 7
Downloading the software .................................................................................................................................. 7
Installing the hardware ....................................................................................................................................... 7
Installing on a Windows platform ..................................................................................................................................... 7
Calibrating the hardware..................................................................................................................................... 7
Chapter 3
Functional Details ................................................................................................................................. 8
Analog input acquisition modes ......................................................................................................................... 8
Software paced .................................................................................................................................................................. 8
Hardware paced ................................................................................................................................................................ 8
Board components .............................................................................................................................................. 9
USB connector .................................................................................................................................................................. 9
LED .................................................................................................................................................................................. 9
Header connectors............................................................................................................................................................. 9
Differential mode pinout ..................................................................................................................................................10
Single-ended mode pinout ...............................................................................................................................................10
Signal connections ............................................................................................................................................ 11
Analog input ....................................................................................................................................................................11
Analog output ..................................................................................................................................................................13
Digital I/O ........................................................................................................................................................................14
Counter input ...................................................................................................................................................................15
External trigger input .......................................................................................................................................................15
SYNC I/O ........................................................................................................................................................................15
Power output ....................................................................................................................................................................15
Ground .............................................................................................................................................................................15
Accuracy ........................................................................................................................................................... 15
Synchronized operations................................................................................................................................... 17
Power ................................................................................................................................................................ 18
Mechanical drawings ........................................................................................................................................ 18
Chapter 4
Specifications ...................................................................................................................................... 19
Analog input ..................................................................................................................................................... 19
Accuracy ..........................................................................................................................................................................20
Noise performance ...........................................................................................................................................................20
Analog output ................................................................................................................................................... 21
Digital input/output........................................................................................................................................... 21
External trigger ................................................................................................................................................. 22
External clock input/output............................................................................................................................... 22
Counter ............................................................................................................................................................. 23
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USB-1208FS-Plus-OEM User's Guide
Memory ............................................................................................................................................................ 23
Microcontroller ................................................................................................................................................. 23
Power ................................................................................................................................................................ 23
General ............................................................................................................................................................. 24
Environmental .................................................................................................................................................. 24
Mechanical ....................................................................................................................................................... 24
Signal connector ............................................................................................................................................... 24
Differential mode signals .................................................................................................................................................25
Single-ended mode signals...............................................................................................................................................25
4
Preface
About this User's Guide
What you will learn from this user's guide
This user's guide describes the Measurement Computing USB-1208FS-Plus-OEM data acquisition device and
lists device specifications.
Conventions in this user's guide
For more information
Text presented in a box signifies additional information and helpful hints related to the subject matter.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
bold text
Bold text is used for the names of objects on a screen, such as buttons, text boxes, and check boxes.
italic text
Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase.
Where to find more information
Additional information about USB-1208FS-Plus-OEM hardware is available on our website at
www.mccdaq.com. You can also contact Measurement Computing Corporation with specific questions.




Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: techsupport@mccdaq.com
Phone: 508-946-5100 and follow the instructions for reaching Tech Support
For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International.
5
Chapter 1
Introducing the USB-1208FS-Plus-OEM
The USB-1208FS-Plus-OEM is a USB 2.0 full-speed analog input and digital I/O data acquisition device that
provides the following features:







Eight analog input channels that are software-selectable for either eight 11-bit single-ended inputs or four
12-bit differential inputs
Two 12-bit analog output channels
16 digital I/O channels that are independently-selectable as input or output in two 8-bit ports
32-bit event counter input for counting TTL pulses
External digital trigger input
Bidirectional external clock for synchronous operation with more than one device.
Two header connectors for field wiring connections
The USB-1208FS-Plus-OEM device is compatible with both USB 1.1 and USB 2.0 ports. The speed of the
device may be limited when using a USB 1.1 port due to the difference in transfer rates on the USB 1.1 versions
of the protocol (low-speed and full-speed).
The device is powered by the +5 V USB supply from the computer. No external power is required.
Caution! There are no product safety, electromagnetic compatibility (EMC), or CE marking compliance
claims made for the USB-1208FS-Plus-OEM. The USB-1208FS-Plus-OEM is intended for use as
a component of a larger system. MCC can help developers meet their compliance requirements.
The end product supplier, however, is responsible for conforming to any and all compliance
requirements.
Functional block diagram
Device functions are illustrated in the block diagram shown here.
Figure 1. USB-1208FS-Plus-OEM functional block diagram
6
Chapter 2
Installing the USB-1208FS-Plus-OEM
Unpacking
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the board from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.
Downloading the software
Refer to the USB-1208FS-Plus-OEM product page on the Measurement Computing website for information
about the supported software you can download.
Install the software before you install the hardware
The driver needed to run the device is installed when you install the software. Therefore, you need to install the
software package you plan to use before you install the hardware.
Installing the hardware
Installing on a Windows platform
Connect the USB-1208FS-Plus-OEM to a to an available USB port on the computer running Windows, connect
the USB cable to an available USB port on the computer or to an external USB hub connected to the computer.
Connect the other end of the cable to the USB connector on the device. No external power is required.
When connected for the first time, a Found New Hardware dialog opens when the operating system detects the
device. When the dialog closes, the installation is complete. The device LED turns on after the device is
successfully installed.
If the LED turns off
If communication is lost between the device and the computer, the LED turns off. To restore communication,
disconnect the USB cable from the computer and then reconnect it. This should restore communication, and the
LED should turn on.
Calibrating the hardware
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Return
the device to Measurement Computing Corporation when calibration is required. The recommended calibration
interval is one year.
The USB-1208FS-Plus-OEM does not support field calibration.
7
Chapter 3
Functional Details
Analog input acquisition modes
The USB-1208FS-Plus-OEM can acquire analog input data in either software paced or hardware paced mode.
Software paced
The USB-1208FS-Plus-OEM acquires data one analog sample at a time using software paced mode. You
initiate the A/D conversion by calling a software command. The analog value is converted to digital and
returned to the computer. You can repeat this procedure until you have the total number of samples that you
want.
The maximum sample rate in software-paced mode is system-dependent.
Hardware paced
The USB-1208FS-Plus-OEM can acquire data from up to eight channels using hardware-paced mode. The
analog data is acquired and converted to digital values until you stop the scan. Data is transferred in blocks of
32 samples from the device to the memory buffer on your computer.
The A/D converter is paced by either an internal or external clock source.
The maximum sample rate is an aggregate rate. The total sample rate for all channels cannot exceed 50 kS/s.
The following table lists the sample rate when scanning from one to eight channels.
Maximum per channel sample rate
# channels
scanned
Sample rate
(kS/s)
1
2
3
4
5
6
7
8
50
25
16.70
12.50
10
8.30
7.14
6.25
You can start a hardware-paced scan with a software command. Optionally, hardware-paced scans can be
delayed by an external hardware trigger event.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Board components
The board components – header connectors, LED, and USB connector –are shown in Figure 2.
1
2
Header connector pins 21 to 40
LED
3
4
USB connector
Header connector pins 1 to 20
Figure 2. Board components
USB connector
Receives the supplied USB cable. When connected to a computer or USB hub, the cable provides power and
communication. No external power supply is required.
LED
The following table lists the behavior of the device LED.
LED state
Indication
Steady green
Blinks continuously
The device is connected to a computer or external USB hub.
Data is being transferred.
Header connectors
The header connectors provide the following connections:








Eight analog input connections (CH0 IN to CH7 IN, CH0 IN HI/LO through CH3 IN HI/LO)
Two analog output connections (D/A OUT 0 to D/A OUT 1)
16 digital I/O connections (PortA0 to Port A7, and Port B0 to Port B7)
External trigger input (TRIG_IN)
External counter input (CTR)
Bidirectional terminal for external clocking or multi-unit synchronization (SYNC)
Power output (+VO)
Analog ground (AGND) and ground (GND)
The differential and single-ended mode pinouts are shown in the following tables.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Differential mode pinout
Four-channel differential mode pinout
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Signal name
CH0 IN HI
CH0 IN LO
AGND
CH1 IN HI
CH1 IN LO
AGND
CH2 IN HI
CH2 IN LO
AGND
CH3 IN HI
CH3 IN LO
AGND
D/A OUT 0
D/A OUT 1
AGND
Reserved
GND
TRIG_IN
SYNC
CTR
Pin description
Analog input 0+
Analog input 0–
Analog ground
Analog input 1+
Analog input 1–
Analog ground
Analog input 2+
Analog input 2–
Analog ground
Analog input 3+
Analog input 3–
Analog ground
Analog output 0
Analog output 1
Analog ground
Reserved for future use
Ground
Trigger input
Synchronization I/O
Counter input
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5
Port A6
Port A7
GND
+VO
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND
Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
Ground
Power output
Ground
Port B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
Ground
USB connector
Single-ended mode pinout
Eight-channel single-ended mode pinout
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Signal name
CH0 IN
CH1 IN
AGND
CH2 IN
CH3 IN
AGND
CH4 IN
CH5 IN
AGND
CH6 IN
CH7 IN
AGND
D/A OUT 0
D/A OUT 1
AGND
Reserved
GND
TRIG_IN
SYNC
CTR
Pin description
Analog input 0
Analog input 1
Analog ground
Analog input 2
Analog input 3
Analog ground
Analog input 4
Analog input 5
Analog ground
Analog input 6
Analog input 7
Analog ground
Analog output 0
Analog output 1
Analog ground
Reserved for future use
Ground
Trigger input
Synchronization I/O
Counter input
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
USB connector
10
Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5
Port A6
Port A7
GND
+VO
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND
Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
Ground
Power output
Ground
Port B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
Ground
USB-1208FS-Plus-OEM User's Guide
Functional Details
Signal connections
Analog input
You can connect up to eight analog input connections to the header connector pins 1 to 20.
You can configure the analog input channels as eight single-ended channels (CH0 IN through CH7 IN) or four
differential channels (CH0 IN HI/LO through CH3 IN HI/LO). When configured for differential mode, each
analog input has 12-bit resolution. When configured for single-ended mode, each analog input has 11-bit
resolution, due to restrictions imposed by the A/D converter.
Single-ended configuration
When configured for single-ended input mode, the input signal is referenced to signal ground (GND) and
delivered through two wires:


Connect the wire carrying the signal to be measured to CH# IN.
Connect the second wire to AGND.
The input range for single-ended mode is ±10 V. The Single-ended mode pinout is shown in on page 10.
Differential configuration
When configured for differential input mode, the input signal is measured with respect to the low input and
delivered through three wires:



Connect the wire carrying the signal to be measured to CH# IN HI.
Connect the wire carrying the reference signal to CH# IN LO.
Connect the third wire to GND.
The Differential mode pinout is shown in on page 10.
Note: To perform a single-ended measurement using differential channels, connect the signal to CH# IN HI and
ground the associated CH# IN LO input.
A low-noise precision programmable gain amplifier (PGA) is available on differential channels to provide gains
of up to 20 and a dynamic range of up to 12-bits. Differential mode input voltage ranges are ±20 V, ±10 V,
±5 V, ±4 V, ±2.5 V, ±2.0 V, ±1.25 V, and ±1.0 V.
In differential mode, the following two requirements must be met for linear operation:


Any analog input must remain in the −10V to +20V range with respect to ground at all times.
The maximum differential voltage on any given analog input pair must remain within the selected voltage
range.
The input [common-mode voltage + signal] of the differential channel must be in the −10 V to +20 V range in
order to yield a useful result.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
For example, you input a 4 V pp sine wave to CH# IN HI, and apply the same sine wave 180° out of phase to
CH# IN LO. The common mode voltage is 0 V. The differential input voltage swings from 4 V – (–4 V) = 8 V
to –4 V – (4 V) = –8V. Both inputs satisfy the –10 V to +20 V input range requirement, and the differential
voltage is suited for the ±10 V input range (see Figure 3).
Figure 3. Differential voltage example: common mode voltage of 0 V
If you increase the common mode voltage to 11 V, the differential remains at 8 V. Although the [common-mode
voltage + signal] on each input now has a range of +7 V to +15 V, both inputs still satisfy the –10 V to +20 V
input requirement (see Figure 4).
Figure 4. Differential voltage example: common mode voltage of 11 V
If you decrease the common-mode voltage to –7 V, the differential stays at 8 V. However, the solution now
violates the input range condition of –10 V to +20 V. The voltage on each analog input now swings from –3 V
to –11 V. Voltages between –10 V and –3 V are resolved, but those below -10 V are clipped, as shown in
Figure 5.
Figure 5. Differential voltage example: common mode voltage of –7 V
Since the analog inputs are restricted to a −10 V to +20 V signal swing with respect to ground, all ranges except
±20V can realize a linear output for any differential signal with zero common mode voltage and full scale signal
inputs. The ±20 V range is the exception. You cannot put −20 V on CH# IN HI and 0 V on CH# IN LO, since
this violates the input range criteria.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
The table below shows some possible inputs and the expected results.
Sample inputs and differential results
CH# IN HI
CH# IN LO
Result
–20 V
–15 V
–10 V
–10 V
0V
0V
+10 V
+10 V
+15 V
+20 V
0V
+5 V
0V
+10 V
+10 V
+20 V
–10 V
0V
–5 V
0
Invalid
Invalid
–10 V
–20 V
–10 V
–20 V
+20 V
+10 V
+20 V
+20 V
For more information on analog signal connections
For more information on single-ended and differential inputs, refer to the Guide to Signal Connections (this
document is available on our web site at www.mccdaq.com/signals/signals.pdf)
Channel-Gain queue
The channel gain queue feature allows you to set up a scan sequence with a unique per-channel gain setting and
channel sequence. The settings are stored in a channel-gain queue list that is written to local memory on the
device. The gain queue can contain up to eight elements in single-ended mode, and up to four elements in
differential mode.
The elements must be unique and listed in ascending order. An example of a three-element list is shown in the
table below.
Sample channel-gain queue list
Element
Channel
Range
Gain
0
1
2
CH0
CH1
CH3
BIP10V
BIP20V
BIP4V
2
1
5
When a scan begins with the gain queue enabled, the device reads the first element, sets the appropriate channel
number, range, and gain, and then acquires a sample. The properties of the next element are then retrieved, and
another sample is acquired. This sequence continues until all elements in the gain queue have been selected.
When the end of the channel list is detected, the sequence returns to the first element in the list. The sequence
repeats until the specified number of samples is acquired.
Carefully match the gain to the expected voltage range on the associated channel or an over range condition
may occur. Although this condition does not damage the device, it does produce a useless full-scale reading,
and can introduce a long recovery time due to saturation of the input channel.
For more information about analog signal connections
For more information about analog input connections, refer to the Guide to Signal Connections (this document
is available on our web site at www.mccdaq.com/signals/signals.pdf).
Analog output
You can connect up to two analog output connections to D/A OUT 0 and D/A OUT 1. Each channel can be paced
at rates up to 50,000 updates per second. The output range is 0 V to 5 V.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Digital I/O
The device has 16 DIO channels that are configured as two 8-bit ports – Port A and Port B. Port B is high drive.
You can connect up to eight DIO lines to Port A0 to Port A7 and up to eight DIO lines to Port B0 to Port B7.
You can configure each port for either input or output. The digital ports are set for input when the device is
powered on or reset.
When configured for input, the digital I/O terminals can detect the state of any TTL-level. Refer to the
schematic shown in Figure 6.
Figure 6. Schematic showing switch detection by digital channel Port A0
If you set the switch to the +5V input, Port A0 reads TRUE (1). When set to GND, Port A0 reads FALSE (0).
Pull-up/down configuration
All digital I/O lines are pulled high to USB +5 V with a 47 kΩ resistor by default. You can change the
pull-up/down configuration using the internal jumper labeled DIO. You must remove the device housing to
access the jumper on the circuit board.
Complete the following steps to set the jumper for pull-up or pull-down:
1.
2.
Unplug the device from the computer.
Turn the device over and rest the top of the housing on a flat, stable surface.
Caution! The discharge of static electricity can damage some electronic components. Before removing the
USB-1208FS-Plus-OEM from its housing, ground yourself using a wrist strap or touch the
computer chassis or other grounded object to eliminate any stored static charge.
3.
4.
Remove the three screws from the bottom of the device using a #1 Philips head screwdriver.
Hold both the top and bottom sections together, turn the device over and rest it on the surface, then
carefully remove the top section of the case to expose the circuit board.
The user-configurable jumpers are labeled DIO A and DIO B. Figure 7 shows the location of each jumper on
the circuit board.
1
DIO B jumper
2
DIO A jumper
Figure 7. Pull-up/down jumper locations
5.
Set each jumper for pull-up (P/UP) or pull-down (P/DN), as shown in Figure 8. Use the jumper labeled
DIO A to configure Port A, and DIO B to configure Port B.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Figure 8. Pull-up/down jumper configuration
6. Replace the top section of the housing, and fasten it to the bottom section with the three screws.
For more information on digital signal connections
For more information on digital signal connections and digital I/O techniques, refer to the Guide to Signal
Connections (available on our web site at www.mccdaq.com/signals/signals.pdf).
Counter input
The CTR connection is input to the 32-bit external event. The internal counter increments when the TTL levels
transition from low to high. The counter can count frequencies of up to 1 MHz.
External trigger input
The TRIG_IN connection is an external trigger input that you can configure for either rising or falling edge.
SYNC I/O
The SYNC terminal is a bidirectional I/O signal that can be configured as an input (default) or an output.


Configure as an external clock input to pace the A/D conversions from an external source. The SYNC
terminal supports TTL-level input signals of up to 50 kHz.
Configure as an output to pace the conversions on a second device and acquire data from 16 channels using
one clock. For more information about synchronized operations see page 17.
Power output
The +VO connection draws power from the USB connector on the computer.
Caution! The +VO terminal is an output. Do not connect it to an external power supply or you may damage
the device and possibly the computer.
Ground
The analog ground (AGND) terminals provide a common ground for all analog channels.
The digital ground (GND) terminals provide a common ground for the digital, trigger, counter, and sync
channels and the power terminal.
Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Resolution is
often incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 part in
4,096" does indicate what can be resolved, it provides little insight into the quality of an absolute measurement.
Accuracy specifications describe the actual results that can be realized with a measurement device.
There are three types of errors which affect the accuracy of a measurement system:



offset
gain
nonlinearity
The primary error sources are offset and gain. Nonlinearity is small in each device, and is not significant as an
error source with respect to offset and gain.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Figure 9 shows an ideal, error-free transfer function. The typical calibrated accuracy is range-dependent. Refer
to the Accuracy specifications on page 20 for more information. We use a ±10 V range here as an example of
what you can expect when performing a measurement in this range.
Figure 9. Ideal ADC transfer function
The offset error is measured at mid-scale. Ideally, a zero volt input should produce an output code of 2048. Any
deviation from this is an offset error.
Figure 10 shows an example of a transfer function with a ±9.77 mV offset error. Offset error affects all codes
equally by shifting the entire transfer function up or down along the input voltage axis.
The accuracy plots in Figure 10 are drawn for clarity and are not drawn to scale.
Figure 10. ADC transfer function with offset error
Gain error is a change in the slope of the transfer function from the ideal, and is typically expressed as a
percentage of full-scale.
Figure 11 shows the transfer function with gain error. Gain error is easily converted to voltage by multiplying
the full-scale (FS) input by the error.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
The accuracy plots in Figure 11 are drawn for clarity and are not drawn to scale.
Figure 11. ADC Transfer function with gain error
For example, the USB-1208FS-Plus-OEM exhibits a typical calibrated gain error of ±0.2% on all ranges. For
the ±10 V range, this would yield 10 V × ±0.002 = ±20 mV. This means that at full scale, and neglecting the
effect of offset, the measurement would be within 20 mV of the actual value. Note that gain error is expressed
as a ratio. Values near ±FS are more affected from an absolute voltage standpoint than are values near midscale, which see little or no voltage error.
Combining these two error sources in Figure 12, we have a plot of the error band for the ±10 V range. This is a
graphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale.
Figure 12. Error band plot
Synchronized operations
You can connect the SYNC pin of two devices together in a master/slave configuration and acquire data from
the analog inputs of both devices using one clock.
When the SYNC pin is configured as an output, the internal A/D pacer clock signal is sent to the header
connector. Output the clock signal to the SYNC pin of a second device that is configured for A/D pacer input.
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USB-1208FS-Plus-OEM User's Guide
Functional Details
Power
Connecting the device to a computer draws <100 mA of current from the USB +5V supply. When running
applications, the current that can be drawn from all device connections (analog, digital, SYNC, and +VO output
loading) is <500 mA. The maximum output current that is available at the +VO power output terminal is
100 mA.
With all outputs at their maximum output current, the USB-1208FS-Plus-OEM in a fully-loaded configuration
may be above that allowed by the computer. In this case, determine the per-pin loading in the application to
ensure that the maximum loading criteria is met. The per-pin loading is calculated by dividing +5V by the load
impedance of the pin in question.
Mechanical drawings
Figure 13. Circuit board dimensions
18
Chapter 4
Specifications
All specifications are subject to change without notice.
Typical for 25°C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog input
Table 1. Analog input specifications
Parameter
Condition
A/D converter type
Input voltage range for linear operation
CHx to GND
Absolute maximum input voltage
Input impedance
Input current (Note 1)
Number of channels
Input ranges
Throughput (Note 2)
Specification
CHx to GND
Vin = +10 V
Vin = 0 V
Vin = –10 V
Single-ended
Differential
Software paced
Continuous scan
Channel gain queue
Resolution (Note 3)
Differential
Single-ended
Integral linearity error
Differential linearity error
Repeatability
Trigger source
Software-selectable
Pacer source
Software-selectable
Successive approximation type
Single-ended mode: ±10 V max
Differential mode: –10 V min, +20 V max
±28 V max
122 kΩ
70 µA typ
–12 µA typ
–94 µA typ
8 single-ended or 4 differential; software-selectable
±10 V, G=2
±20 V, G=1
±10 V, G=2
±5 V,
G=4
±4 V,
G=5
±2.5 V, G=8
±2.0 V, G=10
±1.25 V, G=16
±1.0 V, G=20
Software-selectable
250 S/s typ, PC-dependent
0.014 S/s to 50 kS/s
Software selectable. 8 elements in SE mode,
4 elements in DIFF mode.
One gain element per channel. Elements must be
unique and listed in ascending order.
12 bits, no missing codes
11 bits
±1 LSB typ
±0.5 LSB typ
±1 LSB typ
External digital: TRIG_IN
Software-selectable
 Internal
 External (SYNC), rising edge triggered
Software-selectable
Note 1: Input current is a function of applied voltage on the analog input channels. For a given input
voltage, Vin, the input leakage is approximately equal to (8.181 * Vin – 12) µA.
Note 2: Maximum throughput when scanning is machine dependent.
Note 3: The AD7870 converter only returns 11 bits (0 to 2,047 codes) in single-ended mode.
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USB-1208FS-Plus-OEM User's Guide
Specifications
Accuracy
Table 2. Accuracy, differential mode
Range
Accuracy (LSB)
±20 V
±10 V
±5 V
±4 V
±2.5 V
±2 V
±1.25 V
±1 V
5.1
6.1
8.1
9.1
12.1
14.1
20.1
24.1
Table 3. Accuracy, single-ended mode
Range
Accuracy (LSB)
±10 V
4.0
Table 4. Accuracy components, differential mode – all values are (±)
Range
% of Reading
Gain Error at FS (mV)
Offset (mV)
Accuracy at FS (mV)
±20 V
±10 V
±5 V
±4 V
±2.5 V
±2 V
±1.25 V
±1 V
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
40
20
10
8
5
4
2.5
2
9.766
9.766
9.766
9.766
9.766
9.766
9.766
9.766
49.766
29.766
19.766
17.766
14.766
13.766
12.266
11.766
Table 5. Accuracy components, single-ended mode – all values are (±)
Range
% of Reading
Gain Error at FS (mV)
Offset (mV)
Accuracy at FS (mV)
±10 V
0.2
20
19.531
39.531
Noise performance
Table 6. Noise performance, differential mode
Range
Typical counts
LSBrms
±20 V
±10 V
±5 V
±4 V
±2.5 V
±2 V
±1.25 V
±1 V
2
2
3
3
4
5
7
8
0.30
0.30
0.45
0.45
0.61
0.76
1.06
1.21
Table 7. Noise performance, single-ended mode
Range
Typical counts
LSBrms
±10 V
2
0.30
20
USB-1208FS-Plus-OEM User's Guide
Specifications
Analog output
Table 8. Analog output specifications
Parameter
Resolution
Output range
Number of channels
Throughput (Note 4)
Power on and reset voltage
Output drive
Slew rate
Condition
Specification
Software paced
Hardware paced
12-bits, 1 in 4,096
0 V to 5.0 V
2
250 S/s single channel typ, PC dependent
50 kS/s max per channel
Initializes to 000h code
5 mA, sourcing
0.8 V/ µs typ
Each D/A OUT
Note 4: Maximum throughput when scanning is machine dependent.
Table 9. Analog output accuracy, all values are (±); accuracy tested at no load
Range
Accuracy (LSB)
0 V to 5.0 V
4.0 typ, 45.0 max
Table 10. Analog output accuracy components, all values are (±)
Range
% of FSR
Gain Error at FS (mV)
0 V to 5.0 V
0.1 typ, 0.9 max
4.0 typ, 36.0 max
Offset (mV)
(Note 5)
1.0 typ, 9.0 max
Accuracy at FS (mV)
4.0 typ, 45.0 max
Note 5: Zero-scale offsets may result in a fixed zero-scale error producing a "dead-band” digital input code
region. In this case, changes in digital input code at values less than 0x040 may not produce a
corresponding change in the output voltage. The offset error is tested and specified at code 0x040.
Digital input/output
Table 11. Digital I/O specifications
Parameter
Specification
Digital type
Number of I/O
Configuration
Pull up/pull-down configuration
CMOS
16 (Port A0 through A7, Port B0 through B7)
2 banks of 8. Port B is high current drive.
All pins pulled up to 5 V via 47 kΩ resistors (default). Change to pull-down using
internal user-configurable jumpers.
2.0 V min
5.5 V absolute max
0.8 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –20 µA)
3.84 V min (IOH = –6.0 mA)
0.1 V max (IOL = 20 µA)
0.33 V max (IOL = 6.0 mA)
4.4 V min (IOH = –50 µA)
3.76 V min (IOH = –24.0 mA)
0.1 V max (IOH = 50 µA)
0.44 V max (IOH = 24.0 mA)
Input
Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Output high voltage, Port A
Output low voltage, Port A
Output high voltage, Port B
Output low voltage, Port B
Power on and reset state
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USB-1208FS-Plus-OEM User's Guide
Specifications
External trigger
Table 12. Digital trigger specifications
Parameter
Specification
Trigger source (Note 7)
Trigger mode
External digital; TRIG_IN terminal
Edge sensitive; software-selectable for CMOS compatible rising or falling edge, high
or low level
10 µs max
1 µs min
Schmitt trigger, 47 kΩ pull-down to ground
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min
3.1 V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min
Trigger latency
Trigger pulse width
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
External clock input/output
Table 13. External clock I/O specifications
Parameter
Terminal name
Terminal type
Direction
(software-selectable)
Input clock rate
Clock pulse width
Condition
Specification
SYNC
Bidirectional
Outputs the internal A/D pacer clock
Receives A/D pacer clock from external source
50 kHz, max
1 µs min
5 µs min
Schmitt trigger, 47 kΩ pull-down to ground
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min
3.1 V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min
4.4 V min (IOH = –50 µA)
3.80 V min (IOH = –8 mA)
0.1 V max (IOL = 50 µA)
0.44 V max (IOL = 8 mA)
Output
Input (default)
Input mode
Output mode
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Output high voltage
Output low voltage
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USB-1208FS-Plus-OEM User's Guide
Specifications
Counter
Table 14. Counter specifications
Parameter
Specification
Pin name
Counter type
Number of channels
Input type
Input source
Resolution
Maximum input frequency
High pulse width
Low pulse width
Schmitt trigger hysteresis
CTR
Event counter
1
Schmitt trigger, 47 kΩ pull-down to ground, rising edge triggered
CTR header pin
32 bits
1 MHz
500 ns min
500 ns min
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min
3.1V max
5.5 V absolute max
1.42 V typ
1.0 V min
2.0 V max
–0.5 V absolute min
0 V recommended min
Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Memory
Table 15. Memory specifications
Non-volatile EEPROM
2,048 bytes (768 bytes calibration, 256 bytes user, 1,024 bytes DAQFlex)
Microcontroller
Table 16. Microcontroller specifications
Type
High performance 16-bit RISC microcontroller
Power
Table 17. Power specifications
Parameter
Condition
Specification
Supply current
During USB enumeration
After USB enumeration, including DIO, AO, SYNC,
and +VO output loading
After USB enumeration
After USB enumeration
< 100 mA
< 500 mA
+VO power available
+VO output current
23
4.5 V min, 5.25 V max
100 mA max
USB-1208FS-Plus-OEM User's Guide
Specifications
General
Table 18. General specifications
Parameter
Specification
Device type
Device compatibility
USB 2.0 full speed
USB 1.1, USB 2.0
Environmental
Table 19. Environmental specifications
Parameter
Specification
Operating temperature range
Storage temperature range
Humidity
0 °C to 70 °C
–40 °C to 70 °C
0% to 90% non-condensing
Mechanical
Table 20. Mechanical specifications
Parameter
Specification
Dimensions (L × W × H)
USB cable length
User connection length
81.28 × 73.66 × 15.24 mm (3.20 × 2.9 × 0.6 in.)
3 m (9.84 ft) max
3 m (9.84 ft) max
Signal connector
Table 21. Header specifications
Parameter
Specification
Connector type
Two 20-pin, 0.1 in. pitch headers
24
USB-1208FS-Plus-OEM User's Guide
Specifications
Differential mode signals
Table 22. 4-channel differential mode
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Signal name
CH0 IN HI
CH0 IN LO
AGND
CH1 IN HI
CH1 IN LO
AGND
CH2 IN HI
CH2 IN LO
AGND
CH3 IN HI
CH3 IN LO
AGND
D/A OUT 0
D/A OUT 1
AGND
Reserved
GND
TRIG_IN
SYNC
CTR
Pin description
Analog input 0+
Analog input 0–
Analog ground
Analog input 1+
Analog input 1–
Analog ground
Analog input 2+
Analog input 2–
Analog ground
Analog input 3+
Analog input 3–
Analog ground
Analog output 0
Analog output 1
Analog ground
Reserved for future use
Ground
Trigger input
Synchronization I/O
Counter input
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5
Port A6
Port A7
GND
+VO
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND
Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
Ground
Power output
Ground
Port B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
Ground
Single-ended mode signals
Table 23. 8-channel single-ended mode
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Signal name
CH0 IN
CH1 IN
AGND
CH2 IN
CH3 IN
AGND
CH4 IN
CH5 IN
AGND
CH6 IN
CH7 IN
AGND
D/A OUT 0
D/A OUT 1
AGND
Reserved
GND
TRIG_IN
SYNC
CTR
Pin description
Analog input 0
Analog input 1
Analog ground
Analog input 2
Analog input 3
Analog ground
Analog input 4
Analog input 5
Analog ground
Analog input 6
Analog input 7
Analog ground
Analog output 0
Analog output 1
Analog ground
Reserved for future use
Ground
Trigger input
Synchronization I/O
Counter input
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
25
Signal name
Port A0
Port A1
Port A2
Port A3
Port A4
Port A5
Port A6
Port A7
GND
+VO
GND
Port B0
Port B1
Port B2
Port B3
Port B4
Port B5
Port B6
Port B7
GND
Pin description
Port A bit 0
Port A bit 1
Port A bit 2
Port A bit 3
Port A bit 4
Port A bit 5
Port A bit 6
Port A bit 7
Ground
Power output
Ground
Port B bit 0
Port B bit 1
Port B bit 2
Port B bit 3
Port B bit 4
Port B bit 5
Port B bit 6
Port B bit 7
Ground
Measurement Computing Corporation
10 Commerce Way
Suite 1008
Norton, Massachusetts 02766
(508) 946-5100
Fax: (508) 946-9500
E-mail: info@mccdaq.com
www.mccdaq.com
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