USB-7204
Multifunction DAQ Board
User's Guide
Revision 12A
April 2016
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HM USB-7204
Table of Contents
Preface
About this User's Guide ....................................................................................................................... 5
Conventions ........................................................................................................................................................ 5
Where to find more information ......................................................................................................................... 5
Chapter 1
Introducing the USB-7204 .................................................................................................................... 6
USB-7204 block diagram ................................................................................................................................... 7
Chapter 2
Installing the USB-7204 ........................................................................................................................ 8
Unpacking........................................................................................................................................................... 8
Installing the software ........................................................................................................................................ 8
Installing the hardware ....................................................................................................................................... 8
Calibrating the hardware..................................................................................................................................... 9
Factory calibration ............................................................................................................................................................ 9
Field calibration ................................................................................................................................................................ 9
Chapter 3
Functional Details ............................................................................................................................... 10
Analog input modes .......................................................................................................................................... 10
Software paced .................................................................................................................................................................10
Hardware paced ...............................................................................................................................................................10
Board components ............................................................................................................................................ 10
USB connector .................................................................................................................................................................11
OEM connector ................................................................................................................................................................11
Trigger/Sync connector....................................................................................................................................................11
LED indicators .................................................................................................................................................................12
Screw terminals................................................................................................................................................................12
Signal connections ............................................................................................................................................ 13
Analog input ....................................................................................................................................................................13
Analog output ..................................................................................................................................................................15
Digital I/O ........................................................................................................................................................................15
Trigger input ....................................................................................................................................................................15
SYNC I/O ........................................................................................................................................................................16
Counter input ...................................................................................................................................................................16
Power output ....................................................................................................................................................................16
Ground .............................................................................................................................................................................17
Accuracy ........................................................................................................................................................... 17
Channel gain queue .......................................................................................................................................... 19
Synchronized operations................................................................................................................................... 19
Mechanical drawing ......................................................................................................................................... 20
Chapter 4
Specifications ...................................................................................................................................... 21
Analog input ..................................................................................................................................................... 21
Analog output ................................................................................................................................................... 23
Digital input/output........................................................................................................................................... 23
External trigger ................................................................................................................................................. 24
External clock input/output............................................................................................................................... 24
Counter ............................................................................................................................................................. 25
Non-volatile memory ........................................................................................................................................ 26
Indicator LEDs ................................................................................................................................................. 26
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USB-7204 User's Guide
Power ................................................................................................................................................................ 26
General ............................................................................................................................................................. 27
Environmental .................................................................................................................................................. 27
Mechanical ....................................................................................................................................................... 27
Screw terminal connector ................................................................................................................................. 28
OEM connector and pinout (P4) ....................................................................................................................... 29
Trigger/Sync connector (P5)............................................................................................................................. 30
4
Preface
About this User's Guide
This document describes the Measurement Computing USB-7204 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-7204 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-7204
The USB-7204 is a USB 2.0 full-speed device that provides the following features:






Eight channels of 16-bit analog input configurable for eight 11-bit single-ended inputs (represented as
12-bit data — even values only) or four 12-bit differential inputs.
Two 12-bit analog outputs
16 individually configurable digital I/O channels
32-bit event counter
Digital trigger input
Bidirectional SYNC pin for external clocking and synchronization with another board
The USB-7204 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 USB-7204 is powered by the +5 volt USB supply from your computer; no external power is required. A
USB cable is shipped with the device.
Caution! There are no product safety, electromagnetic compatibility (EMC), or CE marking compliance
claims made for the USB-7204. The USB-7204 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.
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USB-7204 User's Guide
Introducing the USB-7204
USB-7204 block diagram
USB-7204 functions are illustrated in the block diagram shown here.
Figure 1. USB-7204 functional block diagram
7
Chapter 2
Installing the USB-7204
Unpacking
As with any electronic device, you should take care while handling to avoid damage from static electricity.
Before removing the device 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.
Contact us immediately if any components are missing or damaged.
Installing the software
Refer to the MCC DAQ Quick Start and the USB-7204 product page on our website for information about the
available software.
Install the software before you install your device
The driver needed to run the USB-7204 is installed with the software. Therefore, you need to install the
software package you plan to use before you install the hardware.
Installing the hardware
There are two ways to connect the USB-7204 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
below:
Pin
1
3
5
7
9
Signal Name
N/C
N/C
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
Pin
2
4
6
8
10
Signal Name
VBUS
D–
D+
GND
SHIELD
When you connect the USB-7204 for the first time, a Found New Hardware message opens as the device is
detected. The installation is complete when the message closes.
After the USB-7204 is installed, the Power LED remains on to indicate that communication is established
between the USB-7204 and your computer.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
USB-7204, or you may lose data and/or your ability to communicate with the USB-7204.
If the Power LED turns off
If the Power LED is on but then turns off, the computer has lost communication with the USB-7204. 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.
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USB-7204 User's Guide
Installing the USB-7204
Calibrating the hardware
Factory calibration
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Contact
Measurement Computing for details about how to return your device and have it calibrated to the factory
specifications.
Field calibration
The USB-7204 supports field calibration. Calibrate the device using InstaCal whenever the ambient temperature
changes by more than ±10 °C from the last calibration.
9
Chapter 3
Functional Details
Analog input modes
The USB-7204 can acquire analog input data in software paced and continuous scan modes.
Software paced
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 system-dependent.
Hardware paced
You can acquire data from up to eight channels simultaneously in hardware paced 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-7204 to the memory buffer on your computer.
The maximum continuous scan rate of 50 kS/s is an aggregate rate. You can acquire data from one channel at
50 kS/s, two channels at 25 kS/s, and four channels at 12.5 kS/s. You can start a hardware paced scan with
either a software command or with an external hardware trigger event.
Board components
The USB-7204 components are shown in Figure 2.
1
2
3
4
Trigger/Sync connector
Trigger jumper (P7)
Sync jumper (P6)
Pins 1-20
5
6
7
Power LED (top) and Status LED (bottom)
USB connector
Pull-up/down jumper JP2 (Port 0)
Figure 2. Board components
10
8
9
10
OEM connector
Pins 21-40
Pull-up/down jumper JP1 (Port 1)
USB-7204 User's Guide
Functional Details
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
1
3
5
7
9
Signal Name
N/C
N/C
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
Pin
2
4
6
8
10
Signal Name
VBUS
D–
D+
GND
SHIELD
Modifications are required in order to use the OEM connector
We recommend that you return the device to the factory for this modification.
If you have the capabilities to perform the modifications, the following change is required: create a USB
connection via the OEM connector by populating resistor locations R48 and R49; we recommend that you
populate with 0603 size 0 Ω resistors, or provide solder bridges to close the gaps.
Trigger/Sync connector
The Trigger/Sync connector provides two signals — SYNC and TRIG_IN. These signals are also available on
the screw terminal (refer to Trigger input on page 15 for details about these signals).
Trigger/Sync connector pinout
Pin
1
3
5
7
9
Signal Name
TRIG_IN
N/C
SYNC
N/C
N/C
Pin
2
4
6
8
10
Signal Name
GND
GND
GND
GND
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
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USB-7204 User's Guide
Functional Details
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.
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.
LED indicators
The USB-7204 has LEDs for power and communication status. See Figure 2 for the location of each LED.
LED type
Indication
Power
Status
Steady green: The device microcontroller is connected to a computer or external USB hub.
Blinking green: Data is being transferred over the USB bus.
Screw terminals
The screw terminals provide the following connections:








Eight analog input connections (CH0 IN to CH7 IN)
Two analog output connections (D/A OUT 0 to D/A OUT 1)
One external trigger input (TRIG_IN)
One SYNC terminal for external clocking and multi-unit synchronization (SYNC)
One external event counter input (CTR)
16 digital I/O lines (Port 0 bit 0 to bit 7, and Port 1 bit 0 to bit 7)
One output power connection (+5VUSER)
Analog and digital ground connections (AGND and GND)
Screw terminal connections are shown in Figure 4 below.
Figure 4. Screw terminal pinout
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USB-7204 User's Guide
Functional Details
Signal connections
Analog input
You can connect up to eight analog input connections to the screw terminal containing pins 1 to 20 (CH0 IN
through CH7 IN.) You can configure the analog input channels as eight single-ended channels or four
differential channels. By default, differential mode is configured at power-up.
Single-ended configuration
When configured for single-ended mode, each analog input has 11-bit resolution, due to restrictions imposed by
the A/D converter. With single-ended mode, the input signal is referenced to signal ground and delivered
through two wires:


The wire carrying the signal to be measured connects to CH# IN.
The second wire connects to AGND.
The input range for single-ended mode is ±10 V.
Single-ended measurements using differential channels
To perform a SE measurement using differential channels, connect the signal to the "CH# IN HI" input, and
ground the associated "CH# IN LO" input.
Differential configuration
When configured for differential mode, each analog input has 12-bit resolution. In differential mode, the input
signal is measured with respect to the low input and delivered through three wires:



The wire carrying the signal to be measured connects to CH0 IN HI, CH1 IN HI, CH2 IN HI, or
CH3 IN HI.
The wire carrying the reference signal connects to CH0 IN LO, CH1 IN LO, CH2 IN LO, or
CH3 IN LO.
The third wire connects to GND.
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.
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USB-7204 User's Guide
Functional Details
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. For example, you input a 4 V pp sine wave to CHHI, and apply the same sine
wave 180° out of phase to CHLO. 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 5).
Figure 5. 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 [commonmode 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 6).
Figure 6. 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 (see Figure 7).
Figure 7. Differential voltage example: common mode voltage of –7 V
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USB-7204 User's Guide
Functional Details
Since the analog inputs are restricted to a −10 V to +20 V signal swing with respect to ground, all ranges except
±20 V 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 CHHI and 0 V on CHLO since this
violates the input range criteria.
The table below shows some possible inputs and the expected results.
Sample inputs and differential results
CHHI
CHLO
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
Analog output
You can connect up to two analog output connections to screw terminal pins 13 and 14 (D/A OUT 0 and D/A
OUT 1). Each channel can be paced individually at rates up to 10,000 updates per second. Both channels can be
paced simultaneously using the same time base at 5000 updates per channel. The 0v to 4.096 V output range
provides a convenient 1 mV per LSB when setting the output voltage levels.
Digital I/O
The USB-7204 has two eight-bit ports (Port 0 to Bit 0 to Bit 7 and Port 1 to Bit 0 to Bit 7). Each port is
configurable as either input or output.
Pull up/down configuration
The digital pins are configurable via jumpers for pull-up to USB +5 V (HI) or pull-down to ground (LO).
Jumper JP2 configures Port 0, and JP1 configures Port 1. On power up and reset the DIO pins are configured as
input and pulled by JP1/JP2.
Figure 8. Jumper JP0 and JP1 configuration
When configured for input, the digital I/O terminals can be used to detect the state of any TTL level input.
For more information on digital signal connections
For more information on digital signal connections and digital I/O techniques, refer to the Guide to DAQ Signal
Connections (available for download from www.mccdaq.com/support/DAQ-Signal-Connections.aspx.)
Trigger input
The digital trigger input (TRIG_IN) lets you start an acquisition when a signal's rising or falling edge is detected.
This pin is internally connected to the TRIG_IN pin on the Trigger/Sync connector (see page 11).
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USB-7204 User's Guide
Functional Details
SYNC I/O
The SYNC terminal is a bidirectional I/O signal that can be configured as an input or an output (default):


Configure as an external clock input to externally pace the A/D conversions from an external source or
another USB-7204. The SYNC terminal supports TTL-level input signals of up to 50 kHz.
When used as a clock input, the SYNC pin operates in one of two modes – slave or gated slave.
o In slave mode, the USB-7204 ignores the first clock pulse in order to ensure adequate setup time. Use
this mode when the USB-7204 is being paced from a continuous clock source, such as a generator.
o In gated slave mode, it is assumed that the clock signal is held off for an adequate amount of time for
setup to occur. No clock pulses are ignored. Use this mode when the source of the external clock is
another USB-7204.
Configure as an output to pace the conversions on another USB-7204.
When configured as an output, the internal A/D pacer clock is sent to the screw terminal. You can use this
signal as a clock input to a second USB-7204 by connecting it to the SYNC pin and Trig/SYNC connector
of the second device.
The SYNC pin is internally connected to the SYNC pin on the Trigger/Sync connector (see page 11).
Counter input
The CTR connection is a TTL-level input to a 32-bit event counter. Refer to Figure 4 on page 12 for the location
of this pin. 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 output 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-7204
and possibly the computer.
The maximum total output current that can be drawn from all USB-7204 connections (power, analog and digital
outputs) is 420 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.
Just connecting the USB-7204 to your computer draws 80 mA of current from the USB +5 V supply. Once you
start running applications with the USB-7204, each DIO bit can draw up to 2.5 mA, and each analog output can
draw 15 mA. The maximum amount of +5 V current available for experimental use, over and above that
required by the USB-7204, is the difference between the total current requirement of the USB (based on the
application) and the allowed current draw of the computer platform (500 mA for desktop computers and selfpowered hubs, or 100 mA for bus-powered hubs and notebook computers). For Revision C hardware and
earlier, this value shall not exceed 375 mA, based on the current rating of the Slo-Blo Fuse connected to the
+5V terminal; Revision D and later hardware was designed without fuses.
With all outputs at their maximum output current, you can calculate the total current requirement of the USB7204 USB +5 V as follows:
(USB-7204 @ 80 mA) + (16 DIO @ 2.5 mA ea) + (2 AO @ 15 mA ea) = 150 mA
For an application running on a computer or powered hub, the maximum available excess current is
500 mA − 150 mA = 350 mA. This number is the total maximum available current at the +5Vuser power output
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 350 mA to 375 mA range.
Since laptop computers typically allow up to 100 mA, the USB-7204 in a fully-loaded configuration may be
above that allowed by the computer. In this case, you must determine the per-pin loading in the application to
ensure that the maximum loading criteria is met. To calculate the per-pin loading, divide +5 V by the load
impedance of the pin in question.
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USB-7204 User's Guide
Functional Details
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. Quite often,
resolution is incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 part
in 4096" 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 in the USB-7204 are offset and gain. Nonlinearity is small in the USB-7204, and is
not significant as an error source with respect to offset and gain.
Figure 9 shows an ideal, error-free, USB-7204 transfer function. The typical calibrated accuracy of the USB7204 is range-dependent, as explained in the Specifications chapter on page 21. We use a ±10 V range here as
an example of what you can expect when performing a measurement in this range.
The accuracy plots in Figure 9 are drawn for clarity and are not drawn to scale.
Figure 9. Ideal ADC transfer function
The USB-7204 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 the USB-7204 transfer function with an offset
error. The typical offset error specification on the ±10 V range is ±9.77 mV. Offset error affects all codes
equally by shifting the entire transfer function up or down along the input voltage axis.
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USB-7204 User's Guide
Functional Details
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 USB-7204 transfer function with gain error. Gain error is easily
converted to voltage by multiplying the full-scale (FS) input by the error.
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-7204 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, neglecting the effect of offset for the
moment, 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 mid-scale,
which see little or no voltage error.
Combining these two error sources in Figure 12, we have a plot of the error band of the USB-7204 for the
±10 V range. This is a graphical version of the typical accuracy specification of the product.
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USB-7204 User's Guide
Functional Details
The accuracy plots in Figure 12 are drawn for clarity and are not drawn to scale
Figure 12. Error band plot
Channel gain queue
Use the device's channel gain queue to set up a scan sequence with a unique per-channel gain setting and
channel sequence. The queue is large enough for up to 16 channel configurations limited to either single-ended
or differential mode.
The channel gain queue feature removes the restriction of using an ascending channel sequence at a fixed gain.
This feature creates a channel list which is written to local memory on the USB-7204. The channel list is made
up of a channel number and range setting. An example of a four-element list is shown in the table below.
Sample channel gain queue list
Element
Channel
Range
0
1
2
3
CH0
CH0
CH7
CH2
BIP10V
BIP5V
BIP10V
BIP1V
When a scan begins with the gain queue enabled, the USB-7204 reads the first element, sets the appropriate
channel number and range, 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.
This sequence repeats until the specified number of samples is gathered. You must carefully match the gain to
the expected voltage range on the associated channel — otherwise, an over range condition can occur. Although
this condition does not damage the USB-7204, it does produce a useless full-scale reading. It can also introduce
a long recovery time from saturation, which can affect the next measurement in the queue.
Synchronized operations
You can connect the SYNC pin of two USB-7204 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 is sent to the screw terminal. You can use this signal as a clock input to a second USB7204 by connecting it to the SYNC pin and Trig/SYNC connector of the second device.
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USB-7204 User's Guide
Functional Details
Mechanical drawing
Figure 13. Circuit board dimension
20
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
A/D converter type
Input modes
Input voltage range for linear
operation, single-ended mode
Input common-mode voltage range
for linear operation, differential
mode
Absolute maximum input voltage
Input impedance
Input current (Note 1)
Conditions
Specification
CHx to GND
Successive approximation type
Single-ended or differential (default)
±10 V max
CHx to GND
–10 V min, +20 V max
CHx to GND
±28 V max
122 kΩ
70 µA typ
–12 µA typ
–94 µA typ
8 single-ended / 4 differential, software-selectable
Single A/D
Multiplexed
±10 V G=2
±20 V G=1
±10 V G=2 (default)
±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 samples per second (S/s) typ, system dependent
0.596 to 50,000 S/s
Software-selectable channel, range.
12 bits, no missing codes
11 bits
±1 least significant bit (LSB) typ
±0.5 LSB typ
±1 LSB typ
External digital: TRIG_IN
 Internal
 External (SYNC), rising edge triggered
 External Gated (SYNC); refer to Note 4
 Programmed IO
Factory Cal factors stored in firmware. Cal factors
must be applied via application software.
Vin = +10 V
Vin = 0 V
Vin = –10 V
Number of channels
Configuration
Sampling method
Input ranges, single-ended mode
Input ranges, differential mode
Throughput (Note 2)
Channel gain queue
Resolution (Note 3)
Integral linearity error
Differential linearity error
Repeatability
Trigger source
Pacer source
Software paced
Scan to system memory
Up to 16 elements
Differential
Single-ended
Software-selectable
Software-selectable
Calibration
21
USB-7204 User's Guide
Note 1:
Note 2:
Note 3:
Note 4:
Specifications
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.
Maximum throughput scanning to computer memory is machine dependent. The rates specified are for
Windows XP only.
The AD7870 converter only returns 11-bits (0 to 2047 codes) in single-ended mode and 12-bits in differential
mode. Firmware versions prior to 2.04 have LSB justified data. Firmware versions from 2.04 on have MSB
justified data.
External Gated Sync holds off the first clock pulse after setting up a scan to ensure adequate setup time for the
first conversion.
Table 2. Accuracy, differential mode
Range (V)
Accuracy (LSB)
±20
±10
±5
±4
±2.5
±2
±1.25
±1
5.1
6.1
8.1
9.1
12.1
14.1
20.1
24.1
Table 3. Accuracy, single-ended mode
Range (V)
Accuracy (LSB)
±10
4.0
Table 4. Accuracy components, differential mode – All values are (±)
Range (V)
% of Reading
Gain Error at full scale (FS)
(mV)
Offset (mV)
Accuracy at FS (mV)
±20
±10
±5
±4
±2.5
±2
±1.25
±1
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 (V)
% of Reading
Gain Error at FS (mV)
Offset (mV)
Accuracy at FS (mV)
±10
0.2
20
19.531
39.531
Table 6. Noise performance, differential mode
Range (V)
Typical counts
Least significant bitroot mean square (LSBrms)
±20
±10
±5
±4
±2.5
±2
±1.25
±1
2
2
3
3
4
5
7
8
0.30
0.30
0.45
0.45
0.61
0.76
1.06
1.21
22
USB-7204 User's Guide
Specifications
Table 7. Noise performance, single-ended mode
Range (V)
Typical Counts
LSBrms
±10
2
0.30
Analog output
Table 8. Analog output specifications
Parameter
Resolution
Output range
Number of channels
Throughput (Note 5)
Conditions
Software paced
Single channel, continuous scan
Dual channel, continuous scan, simultaneous
update
Power on and reset
voltage
Output drive
Slew rate
Note 5:
Specification
12-bits, 1 in 4096
0 to 4.096 V, 1 mV per LSB
2
250 S/s single channel typ, system dependent
10 kS/s
5 kS/s
Initializes to 000h code
Each D/A OUT
15 mA
0.8V/microsecond (µs) typ
Maximum throughput scanning to computer memory is machine dependent. The rates specified are for
Windows XP only.
Table 9. Analog output accuracy, all values are (±)
Range
Accuracy (LSB)
0 V to 4.096 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 4.096 V
0.1 typ, 0.9 max
4.0 typ, 36.0 max
Note 6:
Offset (mV)
(Note 6)
1.0 typ, 9.0 max
Accuracy at FS
(mV)
4.0 typ, 45.0 max
Negative offsets will result in a fixed zero-scale error or "dead band." At the max offset of 9 mV, any input code
of less than 0x009 will not produce a response in the output.
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 0 bits 0 to 7, Port 1 bits 0 to 7)
2 banks of 8
All pins configurable via jumpers (JP1 and JP2) to Vs or Ground via 47 kΩ resistors.
JP1 configures Port 1, and JP2 configures Port 0.
2.0 V max
5.0 V recommended max
5.5 V absolute max
0.8 V min
0 V recommended min
–0.5 V absolute min
Input
Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Power on and reset state
23
USB-7204 User's Guide
Specifications
Revisions C and earlier (Note 7)
Output high voltage
(IOH = –2.5 mA)
Output low voltage
(IOL = 2.5 mA)
3.8 V min
0.7 V max
Revisions D and later (Note 7)
Output high voltage
(IOH = –6 mA)
Output low voltage
(IOL = 6 mA)
Note 7:
3.84 V min
0.33 V max
The board revision may be determined from the part number label on the board that states "195725X-01L",
where X is the board revision.
External trigger
Table 12. Digital trigger specifications
Parameter
Specification
Trigger source
Trigger mode
Trigger latency
Trigger pulse width
External digital: TRIG_IN input
Edge sensitive. Software-selectable for CMOS compatible rising or falling edge
10 µs max
1 µs min
0 V recommended min
–0.5 V absolute min
5.0 V recommended max
5.5 V absolute max
Input low voltage limit
Input high voltage limit
Revisions C and earlier (Note 7)
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input low voltage threshold
Input leakage current
Schmitt trigger, 1.5 kΩ series resistor
20 mV min
100 mV max
4.0 V max
1.0 V min
±1.0 µA
Revisions D and later (Note 7)
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input low voltage threshold
Schmitt trigger, 47 kΩ pull-down to ground
0.6 V min
1.5 V max
3.1 V max
1.0 V min
External clock input/output
Table 13. External clock I/O specifications
Parameter
Pin name
Pin type
Software-selectable direction
Input clock rate
Clock pulse width
Conditions
Specification
SYNC
Bidirectional
Outputs the internal A/D pacer clock
Receives the A/D pacer clock from an external source
50 kHz, max
1 µs min
5 µs min
Output (default)
Input
Input mode
Output mode
24
USB-7204 User's Guide
Specifications
0 V recommended min
–0.5 V absolute min
5.0 V recommended max
5.5 V absolute max
Input low voltage limit
Input high voltage limit
Revisions C and earlier (Note 7 on page 24)
Input type
Schmitt trigger hysteresis
Input leakage current
Input high voltage threshold
Input low voltage threshold
Output high voltage
Output low voltage
Schmitt trigger, 1.5 kΩ series resistor
20 mV min
100 mV max
±1.0 µA
4.0 V max
1.0 V min
3.3 V min
3.8 V min
1.1 V max
0.6 V max
Input mode
IOH = –2.5 mA
No load
IOL = 2.5 mA
No load
Revisions D and later (Note 7 on page 24)
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input low voltage threshold
Output high voltage
Output low voltage
Schmitt trigger, 47 kΩ pull-down resistor to ground
0.6 V min
1.5 V max
3.1 V max
1.0 V min
3.8 V min
4.4 V min
0.44 V max
0.1 V max
IOH = –8 mA
No load
IOH = 8 mA
No load
Counter
Table 14. Counter specifications
Parameter
Specification
Pin name
Counter type
Number of channels
Input source
Resolution
Input frequency
High pulse width
Low pulse width
Input low voltage limit
CTR
Event counter
1
CTR screw terminal
32 bits
1 MHz max
500 ns min
500 ns min
0 V recommended min
–0.5 V absolute min
5.0 V recommended max
5.5 V absolute max
Input high voltage limit
Revisions C and below (Note 7 on page 24)
Input type
Schmitt trigger hysteresis
Input leakage current
Input high voltage threshold
Input low voltage threshold
Schmitt trigger, rising edge triggered, 1.5 kΩ series resistor
20 mV min
100 mV max
±1 µA
4.0 V max
1.0 V min
25
USB-7204 User's Guide
Parameter
Specifications
Specification
Revisions D and above (Note 7 on page 24)
Input type
Schmitt trigger hysteresis
Input high voltage threshold
Input low voltage threshold
Schmitt trigger, rising edge triggered, 47 kΩ pull-down to ground
0.6 V min
1.5 V max
3.1 V max
1.0 V min
Non-volatile memory
Table 15. Non-volatile memory specifications
Parameter
Specification
EEPROM
EEPROM Configuration
1,024 bytes
Address Range
Access
Description
0x000-0x1FF
0x200-0x3FF
Reserved
Read/write
512 bytes system and cal data
512 bytes user area
Indicator LEDs
Table 16. Indicator LED specifications
Parameter
Specification
Power LED (top)
On when the device microcontroller has power and is configured.
Both LEDs blink together in firmware update mode on revision D and above (see Note 7
on page 24 )
Blinks to indicate USB communications.
OEM connector; LED sink current up to 5 mA per LED @ 5 Vmax
Status LED
OEM power
Power
Table 17. Power specifications
Parameter
Conditions
Supply current (Note 8)
+5VUSER power available
(Note 9)

Output current (Note 10)
Note 8:
Note 9:
Note 10:
Specification
Connected to self-powered hub
 Connected to externally-powered root port hub
Connected to bus-powered hub
Connected to self-powered hub
Connected to externally-powered root port hub
Connected to bus-powered hub
80 mA
4.0 V min, 5.25 V max
4.0 V min, 5.25 V max
420 mA max
20 mA max
This is the total current requirement for the device which includes up to 10 mA for the status LED.
Self-powered hub refers to a USB hub with an external power supply. Self-powered hubs allow a connected
USB device to draw up to 500 mA.
Root port hubs reside in the computer's USB host controller. The USB port(s) on your computer are root port
hubs. All externally powered root port hubs provide up to 500 mA of current for a USB device. Batterypowered root port hubs provide 100 mA or 500 mA, depending upon the manufacturer. A laptop computer that
is not connected to an external power adapter is an example of a battery-powered root port hub.
Bus powered hubs receive power from a self-powered or root port hub. The max current available from the
+5VUSER output is 100 mA; the minimum USB +5V voltage level can be as low as 4.1 V.
This value is the total amount of current that can be sourced from the +5VUSER power output, analog outputs and
digital outputs.
26
USB-7204 User's Guide
Specifications
General
Table 18. General specifications
Parameter
Specification
Device type
Device compatibility
DEFAULTS for
programmable options and
"DEV:RESET/DEFAULT"
message
USB 2.0 (full-speed)
USB 1.1, USB 2.0
AI
Channel Mode = Differential
Range = ±10 V
AInScan
Low Channel = 0
High Channel = 0
Samples = 1000
Rate = 1000
Range = ±10 V
Pacer = Master
Transfer Mode = BlockIO
Trigger = Disabled
Queue = Disabled
Status = Idle
AITrig
Trigger Polarity = Rising
Rearm – Disabled
AOutScan
Low Channel = 0
High Channel = 0
Samples = 1000
Rate = 1000
Trigger = Disabled
Status = Idle
CTR
Value = 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)
90.17 × 95.25 × 12.70 mm (3.55 × 3.75 × 0.5 in.)
111.76 mm (4.40 in.) length with detachable screw terminals connected
3 m (9.84 ft) max
3 m (9.84 ft) max
USB cable length
User connection length
27
USB-7204 User's Guide
Specifications
Screw terminal connector
Table 21. Screw terminal connector specifications
Parameter
Specification
Connector type
Wire gauge range
Screw terminal
16 AWG to 30 AWG
Table 22. 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
N/C (no connect)
GND
TRIG_IN
SYNC
CTR
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
Signal Name
Port 0 Bit 0
Port 0 Bit 1
Port 0 Bit 2
Port 0 Bit 3
Port 0 Bit 4
Port 0 Bit 5
Port 0 Bit 6
Port 0 Bit 7
GND
+5VUSER
GND
Port 1 Bit 0
Port 1 Bit 1
Port 1 Bit 2
Port 1 Bit 3
Port 1 Bit 4
Port 1 Bit 5
Port 1 Bit 6
Port 1 Bit 7
GND
Table 23. 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
N/C (no connect)
GND
TRIG_IN
SYNC
CTR
Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
28
Signal Name
Port 0 Bit 0
Port 0 Bit 1
Port 0 Bit 2
Port 0 Bit 3
Port 0 Bit 4
Port 0 Bit 5
Port 0 Bit 6
Port 0 Bit 7
GND
+5VUSER
GND
Port 1 Bit 0
Port 1 Bit 1
Port 1 Bit 2
Port 1 Bit 3
Port 1 Bit 4
Port 1 Bit 5
Port 1 Bit 6
Port 1 Bit 7
GND
USB-7204 User's Guide
Specifications
OEM connector and pinout (P4)
Table 24. OEM connector specifications
Parameter
Specification
Connector type
10 position 2.54 mm (0.1 in.) box header
Table 25. OEM connector pinout
Pin
1
3
5
7
9
Signal Name
N/C
N/C
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
N/C (do not connect anything to this pin)
Pin
2
4
6
8
10
29
Signal Name
VBUS
D–
D+
GND
SHIELD
USB-7204 User's Guide
Specifications
Trigger/Sync connector (P5)
Table 26. Trigger/Sync connector specifications
Parameter
Specification
Connector type
10 position 2.54 mm (0.1 in.) box header
Table 27. Trigger/Sync connector pinout
Pin
1
3
5
7
9
Signal Name
TRIG_IN
N/C
SYNC
N/C
N/C
Pin
2
4
6
8
10
30
Signal Name
GND
GND
GND
GND
N/C
Measurement Computing Corporation
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Norton, Massachusetts 02766
(508) 946-5100
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E-mail: info@mccdaq.com
www.mccdaq.com
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