Measurement Computing USB-7202 User manual

USB-7202
Analog and Digital I/O
Document Revision 7
March 2013
© Copyright 2013
User's Guide

HM USB-7202.docx
Your new Measurement Computing product comes with a fantastic extra —
Management committed to your satisfaction!
Thank you for choosing a Measurement Computing product—and congratulations! You own the finest, and you can now enjoy
the protection of the most comprehensive warranties and unmatched phone tech support. It’s the embodiment of our mission:
To provide data acquisition hardware and software that will save time and save money.
Simple installations minimize the time between setting up your system and actually making measurements. We offer quick and
simple access to outstanding live FREE technical support to help integrate MCC products into a DAQ system.
Limited Lifetime Warranty: Most MCC products are covered by a limited lifetime warranty against defects in materials or
workmanship for the life of the product, to the original purchaser, unless otherwise noted. Any products found to be defective in
material or workmanship will be repaired, replaced with same or similar device, or refunded at MCC’s discretion. For specific
information, please refer to the terms and conditions of sale.
Harsh Environment Program: Any Measurement Computing product that is damaged due to misuse, or any reason, may be
eligible for replacement with the same or similar device for 50% of the current list price. I/O boards face some harsh
environments, some harsher than the boards are designed to withstand. Contact MCC to determine your product’s eligibility for
this program.
30 Day Money-Back Guarantee: Any Measurement Computing Corporation product may be returned within 30 days of
purchase for a full refund of the price paid for the product being returned. If you are not satisfied, or chose the wrong product by
mistake, you do not have to keep it.
These warranties are in lieu of all other warranties, expressed or implied, including any implied warranty of merchantability or
fitness for a particular application. The remedies provided herein are the buyer’s sole and exclusive remedies. Neither
Measurement Computing Corporation, nor its employees shall be liable for any direct or indirect, special, incidental or
consequential damage arising from the use of its products, even if Measurement Computing Corporation has been notified in
advance of the possibility of such damages.
Trademark and Copyright Information
Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo are either trademarks
or registered trademarks of Measurement Computing Corporation. Refer to the Copyrights & Trademarks section on
mccdaq.com/legal for more information about Measurement Computing trademarks. Other product and company names
mentioned herein are trademarks or trade names of their respective companies.
© 2013 Measurement Computing Corporation. All rights reserved. No part of this publication may be reproduced, stored in a
retrieval system, or transmitted, in any form by any means, electronic, mechanical, by 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 people.

3
Table of Contents
Preface
About this User's Guide .......................................................................................................................5
Conventions........................................................................................................................................................5
Where to find more information.........................................................................................................................5
Chapter 1
Introducing the USB-7202....................................................................................................................6
Functional block diagram...................................................................................................................................7
Chapter 2
Installing the USB-7202........................................................................................................................8
What comes with your shipment?.......................................................................................................................8
Hardware .......................................................................................................................................................................... 8
Documentation.................................................................................................................................................................. 8
Unpacking the USB-7202...................................................................................................................................8
Installing the software ........................................................................................................................................8
DAQFlex .......................................................................................................................................................................... 8
Universal Library and InstaCal......................................................................................................................................... 9
Installing the hardware .......................................................................................................................................9
Programming and developing applications.........................................................................................................9
Chapter 3
Functional Details ...............................................................................................................................10
Analog input acquisition modes .......................................................................................................................10
Software paced mode.......................................................................................................................................................10
Continuous scan mode.....................................................................................................................................................10
BURSTIO scan mode ......................................................................................................................................................10
Components......................................................................................................................................................11
USB connector.................................................................................................................................................................11
OEM connector................................................................................................................................................................11
Trigger/Sync connector....................................................................................................................................................12
LED indicators.................................................................................................................................................................12
Screw terminals................................................................................................................................................................13
Signal connections............................................................................................................................................13
Analog input ....................................................................................................................................................................13
Digital I/O........................................................................................................................................................................13
SYNC I/O ........................................................................................................................................................................14
Trigger input....................................................................................................................................................................14
Counter input...................................................................................................................................................................14
Power output....................................................................................................................................................................14
Ground.............................................................................................................................................................................14
Accuracy...........................................................................................................................................................15
Synchronized operations...................................................................................................................................17
Mechanical drawing .........................................................................................................................................18
Chapter 4
Specifications......................................................................................................................................19
Analog input.....................................................................................................................................................19
Digital input/output...........................................................................................................................................20
External trigger.................................................................................................................................................20
External clock input/output...............................................................................................................................21
Counter.............................................................................................................................................................21
Memory ............................................................................................................................................................21
Microcontroller.................................................................................................................................................22

USB-7202 User's Guide
4
Indicator LEDs .................................................................................................................................................22
Power................................................................................................................................................................22
General .............................................................................................................................................................23
Environmental ..................................................................................................................................................23
Mechanical .......................................................................................................................................................23
Screw terminal connector and pinout ...............................................................................................................23
OEM connector and pinout (P4).......................................................................................................................25
Trigger/Sync connector and pinout (P5)...........................................................................................................25
Declaration of Conformity..................................................................................................................26

5
Preface
About this User's Guide
This document describes the National Instruments USB-7202 data acquisition device and lists device
specifications.
Conventions
For more information
Text presented in a box signifies additional information 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-7202 hardware is available on our website at www.mccdaq.com. You can
also contact Measurement Computing Corporation with specific questions.
Knowledgebase: kb.mccdaq.com
Phone: [phone] and follow the instructions for reaching Tech Support
Fax: [phone] to the attention of Tech Support
Email: [e-mail]

6
Chapter 1
Introducing the USB-7202
The USB-7204 is a USB 2.0 full-speed device that is supported under the following operating systems:
Microsoft Windows 7/Vista/XP (32-bit or 64-bit)
Microsoft Windows CE
Macintosh (32-bit or 64-bit)
Linux (32-bit or 64-bit)
The USB-7204 is compatible with both USB 1.1 and USB 2.0 ports.
The device provides the following features:
8 channels of 16-bit analog input
o100 kS/s max total throughput (200 kS/s Burst Mode), 50 kS/s on any one channel
oSimultaneous sampling (1 A/D converter per input)
oIndependently configurable input ranges
8 individually configurable digital I/O channels
32-bit event counter
Digital trigger input
Bidirectional SYNC pin for external clocking and synchronization with another board
USB/104 form factor
Stackable 3.55" x 3.75" board dimensions
The device is powered by the +5 volt USB supply from your computer, and requires no external power.

USB-7202 User's Guide Introducing the USB-7202
7
Functional block diagram
USB-1208HS functions are illustrated in the block diagram shown here.
Figure 1. Functional block diagram

8
Chapter 2
Installing the USB-7202
What comes with your shipment?
The following items are shipped with the USB-7202:
Hardware
USB-7202
USB cable
Optional hardware
OEM connector cable
Documentation
MCC DAQ Quick Start Guide
The Quick Start Guide booklet provides an overview of the MCC DAQ software you received with the device,
and includes information about installing the software. Please read this booklet completely before installing any
software or hardware.
Insert
The operating systems that are supported by the device are listed on the insert, and includes the internet location
where you can download DAQFlex software, and the locations where you can learn more about DAQFlex
software and MCC DAQ software.
Unpacking the USB-7202
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the USB-7202 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.
If any components are missing or damaged, contact us immediately using one of the following methods:
Knowledgebase: kb.mccdaq.com
Phone: [phone] and follow the instructions for reaching Tech Support
Fax: [phone] to the attention of Tech Support
Email: [e-mail]
For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International.
Installing the software
Note: Before installing the USB-7202 hardware, you must install the software you plan to use with the device.
The USB-7202 is supported by DAQFlex software and Universal Library software. You can install both
software packages on your computer.
DAQFlex
Install DAQFlex software when you want to develop data acquisition applications that can be deployed across
multiple operating systems and custom embedded systems.
DAQFlex software for each supported operating system is available from the DAQFlex download page at
www.mccdaq.com/DAQFlexDL. Refer to the DAQFlex Software User's Guide at
www.mccdaq.com/pdfs/manuals/DAQFlex%20Software.pdf for instructions about how to installing DAQFlex
software.

USB-7202 User's Guide Installing the USB-7202
9
Universal Library and InstaCal
Install Universal Library and InstaCal when you want to develop data acquisition applications using Windows
programming languages.
Universal Library and InstaCal software are included on the CD that ships with the device. Refer to the Quick
Start Guide booklet for instructions about installing Universal Library and InstaCal software.
Installing the hardware
Install the software before you install your device
A driver needed to run the USB-7202 is installed when you install the software. Therefore, you need to install
the software package you plan to use before you install the hardware.
For operation on a Windows operating system, we recommend that you run Windows Update to update your
operating system with the latest USB drivers.
There are two ways to connect the USB-7202 to your system:
Connect a USB cable from the USB connector to either a USB port on the computer or to an external USB
hub connected to the computer. No external power is required.
or
Use a 2.54 mm (0.1 in.) box header to connect with the OEM connector. The connector pinout is shown
here:
Pin
Signal Name
Pin
Signal Name
1
N/C
2
VBUS
3
N/C
4
D–
5
N/C (do not connect anything to this pin)
6
D+
7
N/C (do not connect anything to this pin)
8
GND
9
N/C (do not connect anything to this pin)
10
SHIELD
When you connect the USB-7202 for the first time on a computer running Windows, a Found New Hardware
message opens as the device is detected. The installation is complete when the message closes.
After the USB-7202 is installed, the Power LED remains on to indicate that communication is established
between the USB-7202 and your computer.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
USB-7202, or you may lose data and/or your ability to communicate with the USB-7202.
If the Power LED turns off
If the Power LED is on but then turns off, the computer has lost communication with the USB-7202. To restore
communication, disconnect the USB cable from the computer, and then reconnect it. This should restore
communication, and the Power LED should turn on.
Programming and developing applications
You can program and develop applications for the USB-7202 using MCC DAQ software and DAQFlex
software. OEM users can create a custom driver for use with the message-based firmware to interface with the
device.
Refer to the Quick Start Guide for information about the Universal Library and InstaCal.
Refer to the DAQFlex Software User's Guide for information about DAQFlex software.
Refer to the Message-based Firmware Specification for information about the message-based firmware.

10
Chapter 3
Functional Details
Analog input acquisition modes
The USB-7202 can acquire analog input data in software paced, continuous scan, and burst scan modes.
Software paced mode
You can acquire one analog sample at a time in software paced mode. You initiate the A/D conversion by
calling a software command. The analog value is converted to digital data and returned to the computer. You
can repeat this procedure for each channel desired until you have the total number of samples that you want
from each channel.
The maximum throughput sample rate in software paced mode is about 250 S/s, but may vary depending on
your system. You may receive OVERRUN errors at higher rates on some platforms. Using the BURSTIO
mode should resolve these problems.
Continuous scan mode
You can acquire data from up to eight channels simultaneously in continuous scan mode. The analog data is
continuously acquired and converted to digital values until you stop the scan. Data is transferred in blocks of
up to 32 samples from the USB-7202 to the memory buffer on your computer.
The maximum sampling rate is an aggregate rate, where the total sample rate for all channels is 100 kS/s
divided by the number of channels, with a maximum rate of 50 kS/s for any channel. Using this equation, you
can acquire data with the USB-7202 from one channel at 50 kS/s, two channels at 50 kS/s each, four channels
at 25 kS/s each, and so on, up to eight channels at 12.5 kS/s each. You can start a continuous scan with either
a software command or with an external hardware trigger event.
BURSTIO scan mode
In BURSTIO scan mode, you can acquire data with the USB-7202 using the full capacity of its 32K sample
FIFO. The acquired data is then read from the FIFO and transferred to a user memory buffer on the computer.
You can initiate a single acquisition sequence for any number of input channels by either a software
command or an external hardware trigger.
Burst scans are limited to the depth of the on-board memory, as the data is acquired at a rate faster than it can
be transferred to the computer. The maximum sampling rate is an aggregate rate, where the total acquisition
rate for all channels is 200 kS/s divided by the number of channels. The maximum rate for each channel is 50
kS/s. The maximum rate that you can acquire data using burst scan mode is 50 kS/s per channel for one, two,
or four channels, and 25 kS/s per channel for 8 channels.

USB-7202 User's Guide Functional Details
11
Components
The USB-7202 components are shown in Figure 2.
Figure 2. USB-7202 components
USB connector
The USB connector provides +5 V power and communication. The voltage supplied through the USB
connector is system-dependent, and may be less than 5 V. No external power supply is required.
This connector operates in parallel with the OEM connector —do not connect to both the USB connector and
the OEM connector.
OEM connector
The OEM connector operates in parallel with the USB connector —do not connect to both the USB
connector and the OEM connector.
The OEM connector is a 0.1" box header. Pins 2, 4, 6, 8, and 10 provide a USB connection, as listed in the
connector pinout below:
OEM connector pinout
Pin
Signal Name
Pin
Signal Name
1
N/C
2
VBUS
3
N/C
4
D-
5
N/C (do not connect anything to this pin)
6
D+
7
N/C (do not connect anything to this pin)
8
GND
9
N/C (do not connect anything to this pin)
10
SHIELD
Modifications are required in order to use the OEM connector
We recommend that you return the device to the factory for this modification.
Should you have the capabilities to perform the modifications, the following change is required: in order to
create a USB connection via the OEM connector, locations R30and R36 must be populated. We recommend
that you populate with 0603 size 0 Ω resistors or provide solder bridges to close the gaps.

USB-7202 User's Guide Functional Details
12
Trigger/Sync connector
The Trigger/Sync connector provides two signals —SYNC and TRIG_IN. These signals are also available on
the screw terminal (see page 14 for details about these signals).
Trigger/Sync connector pinout
Pin
Signal Name
Pin
Signal Name
1
TRIG_IN
2
GND
3
N/C
4
GND
5
SYNC
6
GND
7
N/C
8
GND
9
N/C
10
N/CD
Use a 0.1" box header when making connections to the Trigger/Sync connector.
The Trigger/Sync connector internally connects its SYNC and TRIG_IN pins to the screw terminal via
jumpers P6 and P7.
Figure 3. Jumper P6 and P7 schematic
Sync jumper (P6)
The Sync jumper internally connects the SYNC pin on the Trigger/Sync connector to the SYNC pin on the
screw terminal. Remove this jumper on boards that will not send/receive the SYNC signal through the
SYNC/TRIG connector. Refer to Figure 2 on page 11 for the location of this jumper.
Trigger jumper (P7)
The Trigger jumper internally connects the TRIG_IN pin on the Trigger/Sync connector to the TRIG_IN pin
on the screw terminal. Remove this jumper on boards that will not send/receive the TRIG signal through the
SYNC/TRIG connector. Refer to Figure 2 on page 11 for the location of this jumper.
LED indicators
The USB-7202 has LEDs for power and communication status. See Figure 2 on page 11 for the location of
each LED.
LED type
Indication
Power
Steady green: The device microcontroller is connected to a computer or external USB hub.
Status
Blinking green: data is being transferred over the USB bus.

USB-7202 User's Guide Functional Details
13
Screw terminals
Screw terminal connections are shown in shown in Error! Reference source not found..
Figure 4. Screw terminal pinout
Use 16 AWG to 30 AWG when making screw terminal connections.
Signal connections
Analog input
You can connect up to eight analog input connections to screw terminals CH0 IN through CH7 IN. Connect
unused analog input terminals to ground terminals during operation. All AI channels are configured for
single-ended input mode. The input voltage ranges are ±10 V, ±5 V, ±2.0 V, ±1.0 V.
Each analog signal is referenced to signal ground (AGND), and requires two wires:
The wire carrying the signal to be measured connects to CH# IN.
The second wire connects to AGND.
Digital I/O
You can connect up to eight digital I/O lines to screw terminals DIO0 to DIO7. Each digital bit is configurable
as either input or output. When configured for input, the digital I/O terminals can be used to detect the state of
any TTL-level input.
Pull-up/down configuration
The digital pins are configurable via jumper JP1 for pull-up to USB +5 V (HI) or pull-down to ground (LO).
On power up and reset the DIO pins are driven high.
Figure 5. Jumper JP1 configuration

USB-7202 User's Guide Functional Details
14
For more information on signal connections
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
DAQ Signal Connections (available on our web site at www.mccdaq.com/signals/signals.pdf).
SYNC I/O
The SYNC connection 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 conversions on a second USB-7202.
The SYNC pin on the screw terminal is internally connected to the SYNC pin on the Trigger/Sync connector
(see page 12).
Trigger input
Use the digital trigger input (TRIG_IN) to start an acquisition when a rising or falling edge is detected on the
signal. This pin is internally connected to the TRIG_IN pin on the Trigger/Sync connector (see page 12).
Counter input
The CTR connection is a TTL-level input to a 32-bit event counter. The internal counter increments when the
TTL level transitions from low to high. The counter can count frequencies of up to 1 MHz.
Power output
The +5VUSER connection is a 5 volt output that is supplied by the host computer.
Caution! Do not connect to an external power supply to this terminal or you may damage the USB-7202
and possibly the computer.
The maximum total output current that can be drawn from all USB-7202 connections (power, analog, and
digital outputs) is 500 mA. This maximum applies to most personal computers and self-powered USB hubs.
Bus-powered hubs and notebook computers may limit the maximum available output current to 100 mA.
The USB-7202 alone draws 150 mA of current from the USB +5 V supply. Once you start running
applications with the USB-7202, each DIO bit can draw up to 2.5 mA. The maximum amount of +5 V current
available for experimental use, over and above that required by the USB-7202, is the difference between the
total current requirement of the USB-7202 (based on the application) and the allowed current draw of the
computer platform (500 mA for desktop computers and self-powered hubs). It shall not exceed 375 mA,
based on the Slo-Blo Fuse current rating connected to the +5V terminal.
With all outputs at their maximum output current, you can calculate the total current requirement of the USB-
7202 USB +5 V as follows:
(USB-7202 @ 150 mA) + (8 DIO @ 2.5 mA ea) = 170 mA
For an application running on a computer or powered hub, the maximum available excess current is
500 mA − 170 mA = 330 mA. This number is the total maximum available current at the +5VUSER screw
terminal. Measurement Computing highly recommends that you figure in a safety factor of 20% below this
maximum current loading for your applications. A conservative, safe user maximum in this case would be in
the 250 mA to 300 mA range.
Since some laptop computers running on battery power only allow up to 100 mA, the USB-7202 may be
above that allowed by the computer. In this case, you must either purchase a self-powered hub or operate the
laptop computer from an external power adapter.
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.

USB-7202 User's Guide Functional Details
15
Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Quite often,
resolution is incorrectly used to quantify the performance of a measurement product. While "16-bits" or "1
part in 65,536" does indicate what can be resolved, it provides little insight into the quality, or accuracy, of an
absolute measurement. Accuracy specifications describe the actual measurement that can be relied upon with
a USB-7202.
There are three types of errors which affect the accuracy of a measurement system:
offset
gain
nonlinearity
The primary error sources in the USB-7202 are offset and gain. Nonlinearity is small in the USB-7202, and is
not significant as an error source with respect to offset and gain.
Figure 6 shows an ideal, error-free, USB-7202 transfer function. The typical calibrated accuracy of the USB-
7202 is range-dependent, as explained in the Specifications chapter on page 19. We use a ±10 V range as an
example of what you can expect when performing a measurement in this range.
The accuracy plots in Figure 6 are drawn for clarity and are not drawn to scale.
Figure 6. Ideal ADC transfer function
The USB-7202 offset error is measured at mid-scale. Ideally, a zero volt input should produce an output code
of 32,768. Any deviation from this is an offset error. Figure 7 shows the USB-7202 transfer function with an
offset error. The typical offset error specification for the USB-7202 on the ±10 V range is ±1.66 mV. Offset
error affects all codes equally by shifting the entire transfer function up or down along the input voltage axis.

USB-7202 User's Guide Functional Details
16
The accuracy plots in Figure 7 are drawn for clarity and are not drawn to scale.
Figure 7. 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 8 shows the USB-7202 transfer function with gain error. Gain error is easily
converted to voltage by multiplying the full-scale input (±10 V) by the error.
The accuracy plots in Figure 8 are drawn for clarity and are not drawn to scale.
Figure 8. ADC Transfer function with gain error
For example, the USB-7202 exhibits a typical calibrated gain error of ±0.04% on all ranges. For the ±10 V
range, this would yield 10 V × ±0.0002 = ±4 mV. This means that at full scale, neglecting the effect of offset
for the moment, the measurement would be within 4 mV of the actual value. Note that gain error is expressed
as a ratio. Values near ±FS (±10 V) are more affected from an absolute voltage standpoint than are values
near mid-scale, which see little or no voltage error.
Combining these two error sources in Figure 9, we have a plot of the error band of the USB-7202 at ±full
scale (±10 V). This plot is a graphical version of the typical accuracy specification of the product.

USB-7202 User's Guide Functional Details
17
The accuracy plots in Figure 9 are drawn for clarity and are not drawn to scale.
Figure 9. Error band plot
Synchronized operations
You can connect the SYNC pin of two USB-7202 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 screw terminal. If jumper P6 is installed, you can
output the clock to the SYNC pin of a second USB-7202 configured for A/D pacer input.
The SYNC pin is available on both the screw terminal connector and on the Trigger/SYNC connector (when
jumper P6 is installed). Refer to page 14 for more information about the SYNC pin.

USB-7202 User's Guide Functional Details
18
Mechanical drawing
Figure 10. Circuit board dimensions

19
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
Conditions
Specification
A/D converter type
16-bit successive approximation type
Number of channels
8 single-ended
Input configuration
Individual A/D per channel
Sampling method
Simultaneous
Absolute maximum input voltage
CHx IN to GND
±15 V max
Input impedance
100 MΩmin
Input ranges
Software-selectable
±10 V, ±5 V, ±2 V, ±1 V
Sampling rate
Scan to system memory
0.6 S/s to 50 kS/s, software-selectable
Burst scan to 32 k sample FIFO
20 S/s to 50 kS/s, software-selectable
Throughput
Software paced
500 S/s all channels, system-dependent
Scan to system memory (Note 1)
(100 kS/s) / (# of channels); maximum of
50 kS/s for any channel
BURSTIO scan to 32 k Sample FIFO
= (200 kS/s) / (# of channels), maximum of
50 kS/s for any channel
Resolution
16 bits
No missing codes
15 bits
Crosstalk
Signal DC–25 kHz
–80 dB
Trigger source
Software-selectable
External digital: TRIG_IN
Calibration
Cal factors stored in firmware. Cal factors
must be applied to data via application
software.
Note 1: Maximum throughput scanning to system memory is machine dependent.
Table 2. Calibrated absolute accuracy
Range
Accuracy (mV)
±10 V
5.66
±5 V
2.98
±2 V
1.31
±1 V
0.68
Table 3. Accuracy components - All values are (±)
Range
% of Reading
Gain error at FS (mV)
Offset (mV)
±10 V
0.04
4.00
1.66
±5 V
0.04
2.00
0.98
±2 V
0.04
0.80
0.51
±1 V
0.04
0.40
0.28

USB-7202 User's Guide Specifications
20
Table 4 summarizes the noise performance for the USB-7202. Noise distribution is determined by gathering
50 K samples with inputs tied to ground at the user connector. Samples are gathered at the maximum specified
sampling rate of 50 kS/s.
Table 4. Noise performance
Range
Typical counts
LSBrms
±10 V
10
1.52
±5 V
10
1.52
±2 V
11
1.67
±1 V
14
2.12
Digital input/output
Table 5. Digital I/O specifications
Parameter
Specification
Digital type
CMOS
Number of I/O
8 (DIO0 through DIO7)
Configuration
Independently configured for input or output
Pull-up/pull-down
configuration
All pins configurable via jumper (JP1) to Vs or ground via 47 kΩ resistors.
Input high voltage
2.0 V min, 5.5 V absolute max
Input low voltage
0.8 V max, –0.5 V absolute min
Output high voltage
(IOH = –2.5 mA)
3.8 V min
Output low voltage
(IOL = 2.5 mA)
0.7 V max
Power on and reset state
Input
External trigger
Table 6. External trigger specifications
Parameter
Conditions
Specification
Trigger source (Note 2)
External digital
TRIG_IN
Trigger mode
Software-selectable
Edge sensitive: user configurable for CMOS compatible rising or
falling edge.
Trigger latency
10 µs max
Trigger pulse width
1µs min
Input high voltage
4.0 V min, 5.5 V absolute max
Input low voltage
1.0 V max, –0.5 V absolute min
Input leakage current
±1.0µA
Note 2: TRIG_IN is a Schmitt trigger input protected with a 1.5K Ohm series resistor.