USB-1608FS
Analog Input and Digital I/O

User's Guide

Document Revision 7A
January 2014
© Copyright 2014

Trademark and Copyright Information
Measurement Computing Corporation, InstaCal, Universal Library, and the Measurement Computing logo areeither 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.
© 2014 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.
NoticeMeasurement 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 ininjury. 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 ofpeople.

HM USB-1608FS

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-1608FS................................................................................................................ 6
Functional block diagram ................................................................................................................................... 6
Chapter 2

Installing the USB-1608FS.................................................................................................................... 7
What comes with your USB-1608FS shipment? ................................................................................................ 7
Hardware .......................................................................................................................................................................... 7
Software ............................................................................................................................................................................ 7
Documentation .................................................................................................................................................................. 7

Unpacking........................................................................................................................................................... 7
Installing the software ........................................................................................................................................ 7
Installing the hardware ....................................................................................................................................... 7
Calibrating the hardware..................................................................................................................................... 8
Chapter 3

Functional Details ................................................................................................................................. 9
Analog input acquisition modes ......................................................................................................................... 9
Software paced .................................................................................................................................................................. 9
Hardware paced ................................................................................................................................................................ 9
BURSTIO ......................................................................................................................................................................... 9External components ........................................................................................................................................ 10
USB connector .................................................................................................................................................................10
LED .................................................................................................................................................................................10
Screw terminals................................................................................................................................................................10Signal connections ............................................................................................................................................ 11
Analog input ....................................................................................................................................................................11
Channel-Gain queue ........................................................................................................................................................12
Digital I/O ........................................................................................................................................................................12
Pull-up/down configuration .............................................................................................................................................12Counter input ...................................................................................................................................................................13
Trigger input ....................................................................................................................................................................13
SYNC I/O ........................................................................................................................................................................13
Calibration output ............................................................................................................................................................13
Ground .............................................................................................................................................................................14
Power output ....................................................................................................................................................................14

Accuracy ........................................................................................................................................................... 14
Synchronized operations................................................................................................................................... 17
Mechanical drawings ........................................................................................................................................ 18
Chapter 4

Specifications ...................................................................................................................................... 19
Analog input ..................................................................................................................................................... 19
Digital I/O ......................................................................................................................................................... 20
External trigger ................................................................................................................................................. 21
External clock input/output............................................................................................................................... 21
Counter ............................................................................................................................................................. 22
Memory ............................................................................................................................................................ 223

USB-1608FS User's Guide

Microcontroller ................................................................................................................................................. 22Power ................................................................................................................................................................ 23
General ............................................................................................................................................................. 23
Environmental .................................................................................................................................................. 23
Mechanical ....................................................................................................................................................... 23
Screw terminal connector and pinout ............................................................................................................... 23
Declaration of Conformity .................................................................................................................. 25

4

Preface

About this User's Guide
What you will learn from this user's guideThis user's guide describes the Measurement Computing USB-1608FS 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 you arereading.
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
For additional information relevant to the operation of your hardware, refer to the Documents subdirectory
where you installed the MCC DAQ software (C:\Program Files\Measurement Computing\DAQ by default), or
search for your device on our website at www.mccdaq.com.

5Chapter 1

Introducing the USB-1608FS
The USB-1608FS is an analog input and digital I/O data acquisition device providing the following features:








Eight 16-bit single-ended (SE) analog input channels
Each input channel has a dedicated A/D converter for simultaneous sampling.
Software-selectable analog input ranges of ±10 V, ±5 V, ±2 V, and ±1 V
Eight individually configurable digital I/O channels
One 32-bit event counter
One external digital trigger input
Bidirectional external clock for synchronous operations with a second device.
Screw terminals for field wiring connections

The device is powered by the +5V USB supply from the computer, and requires no external power.
The USB-1608FS is a full-speed device that is compatible with both USB 1.1 and USB 2.0 ports. The speed ofthe 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).

Functional block diagram
USB-1608FS functions are illustrated in the block diagram shown here.

Figure 1. Functional block diagram

6

Chapter 2

Installing the USB-1608FS
What comes with your USB-1608FS shipment?
The following items are shipped with the USB-1608FS.

Hardware

USB-1608FS
USB cable

Software

MCC DAQ CD

Documentation
In addition to this hardware user's guide, you should also receive the Quick Start Guide. This booklet provides
an overview of the MCC DAQ software you received with the device, and includes information about installingthe software. Please read this booklet completely before installing any software or hardware.

UnpackingAs with any electronic device, take care while handling to avoid damage from static electricity. Before
removing the USB-1608FS from its packaging, ground yourself using a wrist strap or touch either the computer
chassis or other grounded object to eliminate any stored static charge.
If the device is damaged, notify Measurement Computing Corporation immediately by phone, fax, or email.


Knowledgebase: kb.mccdaq.com
Phone: 508-946-5100 and follow the instructions for reaching Tech Support
Fax: 508-946-9500 to the attention of Tech Support
Email: techsupport@mccdaq.com

For international customers, contact your local distributor. Refer to the International Distributors section on our
web site at www.mccdaq.com/International.

Installing the software
Refer to the Quick Start Guide for instructions on installing the software on the MCC DAQ CD. This booklet isavailable in PDF at www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.

Installing the hardware
Be sure you are using the latest system software
Before installing the device, run Windows Update to update your operating system with the latest HID and USB
drivers.
To connect the USB-1608FS to your system, connect the USB cable to a USB port on your computer or to an
external USB hub that is connected to your computer.
The USB-1608FS installs as a composite device with separate devices attached. When you connect the device
for the first time, a Found New Hardware dialog opens as each device interface is detected. This is normal.
After the device is installed its LED will blink and then remain on. This indicates that communication isestablished between the USB-1608FS and your computer.

7

USB-1608FS User's Guide

If the LED turns off
If communication is lost between the device and the computer, the device LED turns off. Disconnect the USB
cable from the computer and then reconnect it. This should restore communication, and the LED should turn on.

Calibrating the hardware
You can calibrate the USB-1608FS with InstaCal. Perform calibration whenever the ambient temperaturechanges by more than ±10 °C from the last calibration.
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Contact
Measurement Computing if you want to have the factory calibration coefficients restored.

8

Chapter 3

Functional Details
Analog input acquisition modes
The USB-1608FS can acquire analog input data in three modes – software paced, hardware paced, and
BURSTIO.

Software paced
The USB-1608FS 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 thecomputer. You can repeat this procedure until you have the total number of samples that you want.
The USB-1608FS can attain throughput rates up to 500 S/s using a software loop. This rate is systemdependent.

Hardware paced
The USB-1608FS can acquire data from up to eight channels simultaneously in hardware-paced mode. The
analog data is acquired, converted to digital values, and written to an onboard FIFO buffer on the USB-1608FS
until you stop the scan. Data is transferred from the USB-1608FS FIFO buffer to the memory buffer on yourcomputer.
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 is 100 kS/s divided by the
number of channels, with a maximum rate of 50 kS/s for any channel. Using this equation, the USB-1608FS canacquire data 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 start a hardware-paced scan with a software command.
Optionally, hardware-paced scans can be delayed by an external hardware trigger event.
BURSTIO
When using BURSTIO, the USB-1608FS can acquire data at higher rates using the full capacity of the
32 kilosample FIFO. The acquired data is then read from the FIFO and transferred to a user buffer in thecomputer after the acquisition is complete. You can initiate a single acquisition sequence of one, two, four, oreight channels with a software command. Optionally, BURSTIO scans can be delayed by an external hardware
trigger event.
When BURSTIO is enabled, the number of samples acquired in a scan is limited to the depth of the onboard
memory. The maximum sample rate in BURSTIO mode is an aggregate rate is 200 kS/s. The maximum sample
rate for all channels is 200 kS/s divided by the number of channels, with a maximum rate of 50 kS/s for any
channel.
The maximum sample rate that you can acquire data using BURSTIO is 50 kS/s each for one, two, or fourchannels, and 25 kS/s each for eight channels.

9

USB-1608FS User's Guide

External components
The external components – screw terminal banks, LED, and USB connector –are shown in Figure 2.

1
2

Screw terminal pins 21 to 40
LED

3
4

Screw terminal pins 1 to 20
USB connector

Figure 2. USB-1608FS components

USB connector
The USB connector provides +5 V power and communication. No external power supply is required.

LED
The LED indicates the communication status; it cannot be disabled. LED states are listed in the table below.
LED behavior
LED state

Indication

On – steady green
Blinks once
Blinks continuously
Blinks three times
Blinks at a slow rate

The device is connected to a computer or external USB hub.
A USB command is received.
Data is being transferred.
Initial communication is established between the USB-1608FS and the computer.
The analog input is configured for external trigger. The LED stops blinking and illuminates
steady green when the trigger is received.

Screw terminals
The screw terminals provide the following connections:









Eight analog inputs (CH0 IN to CH7 IN)
Eight digital I/O lines(DIO0 to DIO7)
One external event counter input (CTR)
One SYNC I/O terminal for external clocking and multi-unit synchronization (SYNC)
One external trigger input (TRIG_IN)
One calibration output (CAL)
One power output (PC +5 V)
analog ground (AGND) and digital ground (GND) connections

10USB-1608FS User's Guide

Use 16 AWG to 30 AWG wire when making connections to the screw terminals. Pinout locations are shown in
Figure 3 below.

Figure 3. Screw terminal pinout

Signal connections
Analog input
You can connect up to eight analog input connections to CH0 IN through CH7 IN. Connect unused analog input
terminals to ground terminals during operation. For example, if you are not using terminal 15 (CH7 IN), connect
this terminal to terminal 16 (AGND).
The analog input channels are configured for single-ended input mode. Each analog signal is referenced tosignal ground (AGND), and requires two wires:

Connect the wire carrying the signal to be measured to CH# IN.
Connect the second wire to AGND.

The input voltage ranges are ±10 V, ±5 V, ±2.0 V, ±1.0 V.
For more information on analog signal connections
For more information on single-ended inputs, refer to the Guide to Signal Connections (this document isavailable on our web site at www.mccdaq.com/signals/signals.pdf).

11USB-1608FS User's Guide

Channel-Gain queue
The channel-gain queue feature allows you to configure a different gain setting for each analog input channel.
The gain settings are stored in a channel-gain queue list that is written to local memory on the device.
The channel-gain queue list must contain all eight channels listed in consecutive order. An example of thechannel-gain queue list is shown in the table below.
Sample channel-gain queue list
Element

Channel

Range

0
1
2
3
4
5
6
7

CH0
CH1
CH2
CH3
CH4
CH5
CH6
CH7

BIP10V
BIP5V
BIP10V
BIP1V
BIP2V
BIP10V
BIP1V
BIP5V

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.

Digital I/O
You can connect up to eight digital I/O lines to DIO0 through DIO7. Each digital channel is individuallyconfigurable for input or output. During initial power on or reset the digital pins are set for input.
The digital I/O terminals can detect the state of any TTL-level input. Refer to the schematic shown in Figure 4.

Figure 4. Schematic showing switch detection by digital channel DIO0

If you set the switch to the +5 V input, DIO0 reads TRUE (1). When set to GND, DIO0 reads FALSE (0).
Pull-up/down configuration
Boards designed with hardware revision E and later have a user-configurable internal jumper to configure thedigital bits for pull-up (default) or pull-down. The hardware revision is listed with the part number on thebottom of the device, for example P/N 193334E.
If the p/n of your board is earlier than hardware revision E, the default configuration is pull-up. To configure forpull-down, the board must be modified at the factory.
If your board has a user-configurable jumper, complete the following steps to set the pull-up/down
configuration:
1.

Unplug the device from the computer.

2.

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 theUSB-1608FS 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.

Remove the three screws from the bottom of the device using a #1 Philips head screwdriver.

4.

Hold both the top and bottom sections together, turn the device over and rest it on the surface, thencarefully remove the top section of the case to expose the circuit board.
12USB-1608FS User's Guide

The user-configurable jumper is labeled DIO. Figure 5 shows the location of the jumper on the circuitboard.

Figure 5. Pull-up/down jumper location

5.

Configure the jumper for pull-up or pull-down, as shown in Figure 6.

Figure 6. 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 general information regarding 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 terminal is a 32-bit event counter that can accept frequency inputs up to 1 MHz. The internal counterincrements when the TTL levels transition from low to high.

Trigger input
The TRIG_IN terminal is an external digital trigger input. The trigger mode is set for edge sensitive, and isconfigurable for rising or falling edge. On power up and reset the trigger mode is set for rising 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 externally source the A/D conversions. The SYNC terminal
supports TTL-level input signals of up to 50 kHz.
Configure as an output to pace conversions on a second USB-1608FS device and acquire data from16 channels. For more information about synchronized operations see page 17.

Calibration output
The CAL terminal is an output that is used to calibrate the USB-1608FS. Do not use this pin for any otherpurpose. Calibration is software-controlled by InstaCal.

13

USB-1608FS User's Guide

GroundThe 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, sync and power
terminals.

Power output
The PC +5V terminal is a 5 volt output that is supplied by the computer. You can use this terminal to supply
power to external devices or circuitry.
Caution! The PC +5V terminal is an output. Do not connect to an external power supply or you may
damage the USB-1608FS and possibly the computer.
The maximum total output current that can be drawn from all USB-1608FS connections (power, analog, anddigital 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. Note:
If the current requirement of the device exceeds the current available from the computer, connect to a selfpowered hub or power the computer with an external power adapter.
The USB-1608FS can draw up to 150 mA max of current from the USB +5V supply. When runningapplications with the device, each DIO bit can source up to 2.5 mA. With all outputs at their maximum output
current, the total current requirement of the PC +5V terminal is calculated as follows:
Total current requirement = (USB-1608FS @ 150 mA) + (8 DIO @ 2.5 mA ea) = 170 mA

The maximum available excess current is the difference between the allowed current draw of the computer
platform and the total output current requirement of the device. For an application running on a computer or
powered hub, the maximum available excess current is calculated as follows:
Maximum excess current = 500 mA – 170 mA = 330 mA

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.

Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Resolution isoften used incorrectly 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 absolutemeasurement. Accuracy specifications describe the actual measurement achievable with a USB-1608FS.
There are three types of errors which affect the accuracy of a measurement system:

offsetgain
nonlinearity

The primary error sources in the USB-1608FS are offset and gain. Nonlinearity is small, and is not significant
as an error source with respect to offset and gain.

14

USB-1608FS User's Guide

Figure 7 shows an ideal, error-free, USB-1608FS transfer function. The typical calibrated accuracy of theUSB-1608FS is range-dependent, as explained in the "Specifications" chapter. We use a ±10 V range as an
example of what you can expect when performing a measurement in this range.

Figure 7. Ideal ADC transfer function

The USB-1608FS offset error is measured at mid-scale. Ideally, a zero volt input should produce an output codeof 32768. Any deviation from this is an offset error. Figure 8 shows the USB-1608FS transfer function with anoffset error. The typical offset error specification for the USB-1608FS 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.
The accuracy plots in Figure 8 are drawn for clarity and are not drawn to scale.

Figure 8. 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 apercentage of full-scale. Figure 9 shows the USB-1608FS 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 9 are drawn for clarity and are not drawn to scale.

15

USB-1608FS User's Guide

Figure 9. ADC Transfer function with gain error

For example, the USB-1608FS 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 forthe moment, the measurement would be within 4 mV of the actual value. Note that gain error is expressed as aratio. Values near ±FS (±10 V) 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 10, we have a plot of the error band of the USB-1608FS at ±full
scale (±10 V). This plot is a graphical version of the typical accuracy specification of the product.
The accuracy plots in Figure 10 are drawn for clarity and are not drawn to scale.

Figure 10. Error band plot16

USB-1608FS User's Guide

Synchronized operations
You can run up to two USB-1608FS devices on most computers. 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 screw
terminal. You can output the clock to the SYNC pin of a second device that is configured for A/D pacer input.
Change to SYNC pin setting not implemented until first scan
When you change the setting of the SYNC pin to input or to output using InstaCal, the change does not takeplace until you run a scan with a USB-1608FS.
Consequently, if you change the SYNC pin from output to input, the SYNC pin remains an output, andconnections to this pin are connections to an output until the first scan runs. This will not damage theUSB-1608FS.
To update the SYNC pin setting before connecting to the SYNC pin, run the InstaCal analog Scan Test.

17

USB-1608FS User's Guide

Mechanical drawings

Figure 11. Circuit board (top) and enclosure 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
A/D converter type
Number of channels
Input configuration
Sampling method
Absolute maximum input voltage
Input impedance
Input ranges
Sampling rate
Throughput

Condition

Specification

CHx IN to GND
Software-selectable
Scan to PC memory
Burst scan to 32 k sample FIFO
Software paced
Hardware paced (Note 1)
BURSTIO ≤ 32,768 total samples(uses onboard FIFO)

Gain queue

Resolution
No missing codes
Crosstalk
CAL output

Signal DC to 25 kHz
User calibration source

CAL output accuracy (Note 2)
CAL current
Trigger source

Software-selectable16-bit successive approximation type8 single-ended
Individual A/D per channel
Simultaneous±15 V max
100 MΩ, min±10 V, ±5 V, ±2 V, ±1 V
0.6 S/s to 50 kS/s, software-selectable
20 S/s to 50 kS/s, software- selectable
500 S/s all channels(100 kS/s) / (# of channels),
50 kS/s max for any channel(200 kS/s) / (# of channels),
50 kS/s max for any channel
Software configurable..
Eight unique, consecutive elements – one gain
element per channel.
16 bits
15 bits–80 dB
0.625 V, 1.25 V, 2.5 V, 5.0 V,
software-selectable±0.5% typ, ±1.0% max±5 mA maxExternal digital: TRIG_IN

Note 1: Maximum throughput when scanning in hardware paced mode is machine dependent.
Note 2: Actual values used for calibration are measured and stored in EEPROM.
Table 2. Calibrated absolute accuracy
Range

Accuracy (mV)

±10 V
±5 V
±2 V
±1 V

5.66
2.98
1.31
0.68

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USB-1608FS User's Guide

Table 3. Accuracy components - All values are (±)
Range% of Reading

Gain error at FS (mV)

Offset (mV)

±10 V
±5 V
±2 V
±1 V

0.04
0.04
0.04
0.04

4.00
2.00
0.80
0.40

1.66
0.98
0.51
0.28

Table 4 summarizes the noise performance for the USB-1608FS. 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
±5 V
±2 V
±1 V

10
10
11
14

1.52
1.52
1.67
2.12

Digital I/O
Table 5. Digital I/O specifications
Parameter

Specification

Digital type
Number of I/O
Configuration
Pull-up/pull-down configuration

CMOS
8 (DIO0 through DIO7)
Independently configured for input or output
All pins pulled up to 5V via 47 kΩ resistors (default).
Hardware revisions E and later may be changed to pull-down using an internaluser-configurable jumper.
Previous revisions can be configured for pull-down at the factory.
2.0 V min
5.5 V absolute max
0.8 V max
–0.5 V absolute min
0 V recommended min
3.8 V min

Input high voltage threshold
Input high voltage limit
Input low voltage threshold
Input low voltage limit
Output high voltage(IOH = –2.5 mA)
Output low voltage(IOL = 2.5 mA)
Power on and reset state

0.44 V max
Input

20

USB-1608FS User's Guide

External trigger
Table 6. External trigger specifications
Parameter

Condition

Specification

Trigger source
Trigger mode

External digital
Software-selectable

TRIG_IN
Edge sensitive: user configurable for CMOS compatible
rising or falling edge.
10 µs max
1µs minSchmitt trigger, 47 kΩ pull-down to ground1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V 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

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 7. External clock I/O specifications
Parameter
Pin name
Pin type
Direction, software-selectable
Input clock rate
Clock pulse width

Condition

Specification
SYNC
Bidirectional
Receives A/D pacer clock from external source
Outputs internal A/D pacer clock
50 kHz, maximum
1µs min
5µs min
Edge sensitive: rising edge
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V 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
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)

Input
OutputInput
OutputInput clock mode
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-1608FS User's Guide

CounterTable 8. Counter specifications
Parameter

Specification

Pin name
Counter type
Number of channels
Input type
Input source
Resolution
Schmitt trigger hysteresis

CTR
Event counter
1
Schmitt trigger, 47 kΩ pull-down to ground
CTR screw terminal
32 bits
1.01 V typ
0.6 V min
1.5 V max
2.43 V typ
1.9 V min3.1V 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
1 MHz
500 ns min
500 ns min

Input high voltage threshold

Input high voltage limit
Input low voltage threshold

Input low voltage limit
Maximum input frequency
High pulse width
Low pulse width

MemoryTable 9. Memory specifications
Parameter

Specification

Data FIFOEEPROM
EEPROM configuration

32,768 samples, 65,536 bytes
1,024 bytes
Address range

AccessDescription

0x000-0x07F
0x080-0x1FF
0x200-0x3FF

Reserved
Read/write
Read/write

128 bytes system data
384 bytes cal data
512 bytes user area

Microcontroller
Table 10. Microcontroller specifications
Parameter

Specification

Type

High performance 32-bit RISC microcontroller

22USB-1608FS User's Guide

Power
Table 11. Power specifications
Parameter

Condition

Specification

Supply current
Supply current (Note 3)
PC +5 V voltage range (Note 4)

USB enumeration
Continuous mode Connected to self-powered hub
 Connected to externally-powered root port hub< 100 mA
150 mA
4.25 V min, 5.25 V max

PC +5V output current (Note 5)

300 mA max

Note 3: This is the total current requirement for the USB-1608FS which includes up to 10 mA for the status

LED.
Note 4: "Self-powered hub" refers to a USB hub with an external power supply. Self-powered hubs allow aconnected USB device to draw up to 500 mA. "Root port hubs" reside in the PC USB host Controller.
The USB port(s) on your PC are root port hubs. All externally-powered root port hubs, such as a
desktop PC, provide up to 500 mA of current for a USB device. Battery-powered root port hubs
provide 100 mA or 500 mA, depending upon the manufacturer. A laptop PC that is not connected to an
external power adapter is an example of a battery-powered root port hub. If your laptop PC isconstrained to the 100 mA maximum, you need to purchase a self-powered hub.
Note 5: This refers to the total amount of current that can be sourced from the USB +5 V and digital outputs.

GeneralTable 12. General specifications
Parameter

Specification

Device type
Device compatibility

USB 2.0 (full-speed)
USB 1.1, USB 2.0

Environmental
Table 13. 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 14. Mechanical specifications
Parameter

Specification

Dimensions (L × W × H)
USB cable length
User connection length

3.10 × 3.20 × 1.05 in. (79 × 82 × 27 mm)
3 m (9.84 ft) max
3 m (9.84 ft) max

Screw terminal connector and pinout
Table 15. Connector specifications
Parameter

Specification

Connector type
Wire gauge range

Screw terminal
16 AWG to 30 AWG

23

USB-1608FS User's Guide

Table 16. Connector 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 INAGND
CH1 INAGND
CH2 IN
AGND
CH3 IN
AGND
CH4 INAGND
CH5 INAGND
CH6 INAGND
CH7 IN
AGND
CAL
AGND
AGND
AGND

Pin
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40

24

Signal Name
DIO0
GND
DIO1
GND
DIO2
GND
DIO3
GND
DIO4
GND
DIO5
GND
DIO6
GND
DIO7
SYNC
TRIG_IN
CTR
PC +5V
GND

Declaration of Conformity
Manufacturer:
Address:

Category:

Measurement Computing Corporation
10 Commerce Way
Suite 1008
Norton, MA 02766
USAElectrical equipment for measurement, control and laboratory use.

Measurement Computing Corporation declares under sole responsibility that the productUSB-1608FS
to which this declaration relates is in conformity with the relevant provisions of the following standards or otherdocuments:
EC EMC Directive 2004/108/EC: General Requirements, EN 61326-1:2006 (IEC 61326-1:2005).
Emissions:EN 55011 (2007) / CISPR 11(2003): Radiated emissions: Group 1, Class A
EN 55011 (2007) / CISPR 11(2003): Conducted emissions: Group 1, Class A

Immunity: EN 61326-1:2006, Table 3.


IEC 61000-4-2 (2001): Electrostatic Discharge immunity.
IEC 61000-4-3 (2002): Radiated Electromagnetic Field immunity.

To maintain compliance to the standards of this declaration, the following conditions must be met.






The host computer, peripheral equipment, power sources, and expansion hardware must be CE
compliant.
All I/O cables must be shielded, with the shields connected to ground.
I/O cables must be less than 3 meters (9.75 feet) in length.
The host computer must be properly grounded.
Equipment must be operated in a controlled electromagnetic environment as defined by Standards EN
61326-1:2006, or IEC 61326-1:2005.

Declaration of Conformity based on tests conducted by Chomerics Test Services, Woburn, MA 01801, USA in
May, 2004. Test records are outlined in Chomerics Test Report #EMI3876.04. Further testing was conducted by
Chomerics Test Services, Woburn, MA. 01801, USA in December, 2008. Test records are outlined in
Chomerics Test report #EMI5215B.08.
We hereby declare that the equipment specified conforms to the above Directives and Standards.

Carl Haapaoja, Director of Quality Assurance

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