Measurement USB-202 User Manual

USB-1608HS-2AO

USB-based High-Speed

Analog and Digital I/O Module

User's Guide

Document Revision 3, September, 2009

© Copyright 2009, Measurement Computing Corporation

HM USB-1608HS-2AO.doc

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3

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4

Table of Contents

Preface

About this User's Guide ....................................................................................................................... 7

What you will learn from this user's guide ......................................................................................................... 7

Conventions in this user's guide ......................................................................................................................... 7

Where to find more information ......................................................................................................................... 7

Chapter 1

Introducing the USB-1608HS-2AO ...................................................................................................... 8

USB-1608HS-2AO block diagram ..................................................................................................................... 9

Software features ................................................................................................................................................ 9

Chapter 2

Installing the USB-1608HS-2AO ........................................................................................................ 10

What comes with your USB-1608HS-2AO shipment? ..................................................................................... 10

Hardware .........................................................................................................................................................................10

Additional documentation ................................................................................................................................................11

Unpacking the USB-1608HS-2AO ................................................................................................................... 11

Installing the software ...................................................................................................................................... 11

Installing the hardware ..................................................................................................................................... 11

Connecting the AC power adapter ...................................................................................................................................11

Connecting the USB-1608HS-2AO to your system .........................................................................................................11

Calibrating the USB-1608HS-2AO .................................................................................................................. 12

Chapter 3

Functional Details ............................................................................................................................... 13

Theory of operation - analog input acquisition modes ..................................................................................... 13

Software paced mode .......................................................................................................................................................13

Continuous scan mode .....................................................................................................................................................13

External components ........................................................................................................................................ 13

USB active LED (ACT) ...................................................................................................................................................14

Power LED (PWR) ..........................................................................................................................................................14

Main connector and pin out .............................................................................................................................................14

USB connector .................................................................................................................................................................14

Power connector ..............................................................................................................................................................15

Analog input terminals (CH0_L - CH7_H) ......................................................................................................................15

Analog voltage output terminals (VDAC0_F, VDAC0_S, VDAC1_F, and VDAC1_S) .................................................17

Analog ground terminals ..................................................................................................................................................18

Digital input terminals (DI0 to DI7) and digital output terminals (DO0 to DO7) ............................................................18

Power terminal (+5V EXT) .............................................................................................................................................19

Counter terminal (CTR) ...................................................................................................................................................19

SYNC terminals (SYNC_IN and SYNC_OUT) ..............................................................................................................20

Trigger terminal (TRIG_IN) ............................................................................................................................................20

Common ground terminals (GND) ..................................................................................................................................23

Chapter 4

Specifications ...................................................................................................................................... 24

Analog input ..................................................................................................................................................... 24

Analog output ................................................................................................................................................... 26

Analog input calibration ................................................................................................................................... 27

Digital input/output........................................................................................................................................... 27

External trigger ................................................................................................................................................. 27

External clock input/output............................................................................................................................... 28

Counter ............................................................................................................................................................. 28

5

USB-1608HS-2AO User's Guide

Memory ............................................................................................................................................................ 28

Microcontroller ................................................................................................................................................. 29

Power ................................................................................................................................................................ 29

External power input ........................................................................................................................................ 29

USB specifications ........................................................................................................................................... 29

Environmental .................................................................................................................................................. 29

Mechanical ....................................................................................................................................................... 30

Main connector and pin out .............................................................................................................................. 30

Declaration of Conformity .................................................................................................................. 32

6

Preface

About this User's Guide

What you will learn from this user's guide

This user's guide explains how to install, configure, and use the USB-1608HS-2AO so that you get the most out
of its USB data acquisition features.

This user's guide also refers you to related documents available on our web site, and to technical support
resources.

Conventions in this user's guide

For more information on …

Text presented in a box signifies additional information and helpful hints related to the subject matter you are
reading.

Caution! Shaded caution statements present information to help you avoid injuring yourself and others,

damaging your hardware, or losing your data.

< : > Angle brackets that enclose numbers separated by a colon signify a range of numbers, such as those assigned

to registers, bit settings, etc.

bold text Bold text is used for the names of objects on the screen, such as buttons, text boxes, and check boxes. For

example:

1. Insert the disk or CD and click the OK button.

italic text Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase. For

example:
The InstaCal installation procedure is explained in the Quick Start Guide.
Never touch the exposed pins or circuit connections on the board.

Where to find more information

The following electronic documents provide helpful information relevant to the operation of the USB-1608HS­2AO.

 MCC's Specifications: USB-1608HS-2AO (the PDF version of the Specifications chapter in this guide) is

available on our web site at www.mccdaq.com/pdfs/USB-1608HS-2AO.pdf.

 MCC's Quick Start Guide is available on our web site at

www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.

 MCC's Guide to Signal Connections is available on our web site at

www.mccdaq.com/signals/signals.pdf.

 MCC's Universal Library User's Guide is available on our web site at

www.mccdaq.com/PDFmanuals/sm-ul-user-guide.pdf.

 MCC's Universal Library Function Reference is available on our web site at

www.mccdaq.com/PDFmanuals/sm-ul-functions.pdf.

 MCC's Universal Library for LabVIEW™ User’s Guide is available on our web site at

www.mccdaq.com/PDFmanuals/SM-UL-LabVIEW.pdf.

USB-1608HS-2AO User's Guide (this document) is also available on our web site at

www.mccdaq.com/PDFmanuals/USB-1608HS-2AO.pdf.

7

Chapter 1

Introducing the USB-1608HS-2AO

This user's guide contains all of the information you need to connect the USB-1608HS-2AO to your computer
and to the signals you want to measure.

The USB-1608HS-2AO is a USB 2.0 high-speed device supported under popular Microsoft® Windows®
operating systems. The USB-1608HS-2AO is fully compatible with both USB 1.1 and USB 2.0 ports.

The USB-1608HS-2AO features the following:
 With one A/D converter per channel, the USB-1608HS-2AO offers true simultaneous-sampling of up to

eight channels of 16-bit single-ended or differential analog input at 250 kHz per channel.
Each channel can be independently-configured with software for either single-ended or differential input.

The input range of each channel can also be configured independently with software.

 Two independent 16-bit analog output channels can be configured with a remote sensing option to

compensate for voltage drop errors that may occur at the field device.

 Eight digital input lines and eight digital output lines.

The digital output lines are driven low on power up and reset. Each digital line has an associated LED
indicator that lights for the logic 1 (high) state. You can disable all input or output LEDs with a jumper–one
jumper disables all input LEDs. A second jumper disables all output LEDs.

 A 32-bit counter capable of counting TTL pulses.
 A 5 V, 2 A, AC adapter (MCC p/n PS-5V2AEPS) powers the USB-1608HS-2AO. This adapter ships with

the device.

 A synchronization input line (SYNC_IN) allows you to provide an external sampling clock for the analog

inputs. A synchronization output line (SYNC_OUT) lets you output the internal or external sampling clock
of the USB-1608HS-2AO analog inputs.

 An analog trigger lets you start analog input conversions based on the value of a digital or analog signal.
The USB-1608HS-2AO is shown in Figure 1. I/O connections are made to the screw terminals on the device.

Figure 1. USB-1608HS-2AO

8

USB-1608HS-2AO User's Guide Introducing the USB-1608HS-2AO

Screw terminal I/O connector

USB

Microcontroller

SPI

Digital

input

32-bit

event counter

1 channel

SYNC_IN

USB

High-speed
USB 2.0
compliant
interface

32k x 16
SRAM

1 8 16

16

16

DAC 1

DAC 0

2

Ch1 force

Ch1 sense

Ch0 force

Ch0 sense

Digital
output

8

CH0_L

CH0_H

CH1_L

CH1_H

CH2_L

CH2_L

CH3_L

CH3_H

CH4_L

CH4_H

CH5_L

CH5_H

CH6_L

CH6_L

CH7_L

CH7_H

G= 1, 2, 5, 10

TRIG_IN

SYNC_OUT

USB-1608HS-2AO block diagram

USB-1608HS-2AO functions are illustrated in the block diagram shown here.

Software features

For information on the features of InstaCal and the other software included with your USB-1608HS-2AO, refer
to the Quick Start Guide that shipped with your device. The Quick Start Guide is also available in PDF at

www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf.

Check www.mccdaq.com/download.htm for the latest software version.

Figure 2. USB-1608HS-2AO functional block diagram

9

Installing the USB-1608HS-2AO

What comes with your USB-1608HS-2AO shipment?

As you unpack your USB-1608HS-2AO, verify that the following components are included.

Hardware

 USB-1608HS-2AO

Chapter 2

 USB cable (2 meter length)

 External power supply and cord – 10 watt AC power adapter. (MCC part number PS-5V2AEPS).

10

USB-1608HS-2AO User's Guide Installing the USB-1608HS-2AO

Additional documentation

In addition to this hardware user's guide, you should also receive the Quick Start Guide (available in PDF at

www.mccdaq.com/PDFmanuals/DAQ-Software-Quick-Start.pdf). This booklet supplies a brief description of

the software you received with your USB-1608HS-2AO and information regarding installation of that software.
Please read this booklet completely before installing any software or hardware.

Unpacking the USB-1608HS-2AO

As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the USB-1608HS-2AO 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 your USB-1608HS-2AO is damaged, notify Measurement Computing Corporation immediately by phone,
fax, or e-mail:

 Phone: [phone] and follow the instructions for reaching Tech Support.
 Fax: [phone] to the attention of Tech Support
 Email: [e-mail]

Installing the software

Refer to the Quick Start Guide for instructions on installing the software on the Measurement Computing Data
Acquisition Software CD.

This booklet is also available 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 you install your USB-1608HS-2AO, run Windows Update to update your operating system with the
latest USB drivers.

Connecting the AC power adapter

Power to the USB-1608HS-2AO is provided with the 5 V adapter (PS-5V2AEPS). To connect the power supply
to your USB-1608HS-2AO, connect the power adapter cord to the power connector on the USB-1608HS-2AO
device, and plug the AC adapter into a power outlet.

The power LED on the device lights up when the USB-1608HS-2AO is receiving power from the AC power
adapter.

Connecting the USB-1608HS-2AO to your system

To connect the USB-1608HS-2AO to your system, turn your computer on, and 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 cable provides
communication to the USB-1608HS-2AO.

When you connect the USB-1608HS-2AO for the first time, a Found New Hardware dialog opens when the
USB-1608HS-2AO interface is detected.

When the dialog closes, the installation is complete. The activity LED on the USB-1608HS-2AO should flash
and then remain lit, indicating the USB-1608HS-2AO is communicating with your computer.

11

USB-1608HS-2AO User's Guide Installing the USB-1608HS-2AO

Caution! Do not disconnect any device from the USB bus while the computer is communicating with the

USB-1608HS-2AO, or you may lose data and/or your ability to communicate with the USB­1608HS-2AO.

If the ACT LED turns off

If the ACT (active) LED lights up but then turns off, the computer has lost communication with the USB­1608HS-2AO. To restore communication, disconnect the USB cable from the computer, and then reconnect it.
This should restore communication, and the LED should light up again.

Calibrating the USB-1608HS-2AO

The USB-1608HS-2AO is shipped fully-calibrated. Calibration coefficients are stored in EEPROM.

You can calibrate the analog inputs on the USB-1608HS-2AO with InstaCal. The normal calibration interval is
once per year.

Calibration is recommended whenever the USB-1608HS-2AO's ambient temperature changes by more than
±10 °C.

Allow the USB-1608HS-2AO to warm up for at least 30 minutes before starting the calibration.

12

Screw terminal pins 1 to 54
USB active LED

Power LED

Chapter 3

Functional Details

Theory of operation - analog input acquisition modes

The USB-1608HS-2AO can acquire analog input data in two basic modes – software paced and continuous
scan.

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 until you have the total number of samples that you want.

The maximum throughput sample rate in software paced mode is system-dependent.

Continuous scan mode

You can acquire data from up to eight channels simultaneously in continuous scan mode. The analog data is
continuously acquired, converted to digital values, and written to an onboard FIFO buffer on the USB-1608HS­2AO until you stop the scan. The FIFO buffer is serviced in blocks as the data is transferred from the USB­1608HS-2AO FIFO buffer to the memory buffer on your computer.

The maximum sampling rate is 250 kS/s per channel for one-to-eight channels. You can start a continuous scan
with either a software command or with an external hardware trigger event.

External components

The USB-1608HS-2AO has the following external components, as shown in Figure 3.

 USB connector
 USB activity (ACT) LED
 Power connector
 Power (PWR) LED
 Screw terminals

Figure 3. USB-1608HS-2AO external components – front view

13

USB-1608HS-2AO User's Guide Functional Details

LED Illumination

Indication

Steady green

The USB-1608HS-2AO is connected to a computer or external USB hub.

Blinks continuously

Data is being transferred.

Connector type

Screw terminal

Wire gauge range

16 AWG to 30 AWG

1 GND

2 DI0

3 DI1

4 DI2

5 DI3

6 DI4

7 DI5

8 DI6

9 DI7

10 GND

11 DO0

12 DO1

13 DO2

14 DO3

15 D04

16 DO5

17 DO6

18 DO7

19 GND

20 SYNC_IN

21 SYNC_OUT

22 +5V EXT

23 CTR

24 TRIG_IN

25 VDAC0_F

26 VDAC0_S

27 AGND

28 VDAC1_F

29 VDAC0_S

30 AGND

31 CH0_L

32 CH0_H

33 AGND

34 CH1_L

35 CH1_H

36 AGND

37 CH2_L

38 CH2_H

39 AGND

40 CH3_L

41 CH3_H

42 AGND

43 CH4_L

44 CH4_H

45 AGND

46 CH5_L

47 CH5_H

48 AGND

49 CH6_L 50 CH6_H

51 AGND

52 CH7_L

53 CH7_H

54 AGND

USB active LED (ACT)

The ACT LED indicates the communication status of the USB-1608HS-2AO. The table below defines the
function of the ACT LED.

LED Illumination

Power LED (PWR)

The PWR LED lights up when the USB-1608HS-2AO is receiving +5 V of power from the AC power adapter.

Main connector and pin out

The USB-1608HS-2AO has one row of screw terminals that provide the following connections:.
 16 analog input connections (CH0_L to CH7_L and CH0_H to CH7_H) covering eight analog input

channels.

 10 analog ground connections (AGND)
 Eight digital input connections (DI0 to DI7)
 Eight digital output connections (DO0 to D07)
 Four analog output connections (VDAC0_F, VDAC0_S, VDAC1_F, VDAC1_S) covering two DAC

channels—only two connections (VDAC0_F and VDAC1_F) needed if remote sensing is disabled

 One external trigger source (TRIG_IN)
 Two SYNC terminals for external clocking and multi-unit synchronization (SYNC_IN and SYNC_OUT)
 One external event counter connection (CTR)
 One voltage connection (+5 V EXT)
 Three digital ground connections (GND)

Signals are identified in Figure 4.

Figure 4. USB-1608HS-2AO screw terminal functions

USB connector

The USB connector is on the rear of the USB-1608HS-2AO. This connector provides communication..

14

USB-1608HS-2AO User's Guide Functional Details

USB connector

Power connector

Power connector

Connect the external power adapter (MCC part number PS-5V2AEPS) to the power connector on the rear of the
USB-1608HS-2AO.

Figure 5. USB-1608HS-2AO external components – rear view

Analog input terminals (CH0_L - CH7_H)

You can connect up to eight analog input connections to these screw terminal pins:

 CH0_H and CH0_L
 CH1_H and CH1_L
 CH2_H and CH2_L
 CH3_H and CH3_L
 CH4_L and CH4_H
 CH5_L and CH5_H
 CH6_L and CH6_H
 CH7_L and CH7_H

Refer to the Figure 4 on page 14 for the location of these pins.

Input configuration

Analog signals are referenced to analog ground (AGND). Single-ended mode requires two wires:

 The wire carrying the signal to be measured connects to CHx_H.
 The second wire connects to AGND.

Differential mode requires three wires:

 The wire carrying the positive portion of the differential signal to be measured connects to CHx_H.
 The wire carrying the negative portion of the differential signal to be measured connects to CHx_L.
 The analog ground reference wire connects to AGND.

The input voltage ranges are ±10 V, ±5 V, ±2.0 V, ±1.0 V. The following image illustrates a typical
single-ended measurement connection.

15

USB-1608HS-2AO User's Guide Functional Details

CH7_H

AGD

The following image depicts a voltage source connected to a USB-1608HS-2AO configured for single-ended
mode.

Figure 6. Single-ended measurement connection

16

USB-1608HS-2AO User's Guide Functional Details

CH7_H

CH7_L

CH7_H

AGD

+5 V

CH7_L

The following image depicts a Wheatstone bridge signal source connected to a USB-1608HS-2AO configured
for differential mode.

Figure 7. Differential measurement connection

For more information on analog signal connections

For more information on single-ended inputs, refer to the Guide to Signal Connections (this document is
available on our web site at www.mccdaq.com/signals/signals.pdf).

Analog voltage output terminals (VDAC0_F, VDAC0_S, VDAC1_F, and VDAC1_S)

You can connect up to two analog voltage outputs to screw terminal pins VDAC0_F and VDAC1_F.

You may also use the VDAC0_S and VDAC1_S when you enable the remote sensing option for the output
channel. Refer to the pinout diagram on page 14 for the location of these pins.

You can enable remote sensing for each analog output on the USB-1608HS-2AO with InstaCal.

The remote sensing feature compensates for the voltage drop error that occurs in applications where the USB­1608HS-2AO's analog outputs are connected to its load through a long wire- or cable-type interconnect.

17

USB-1608HS-2AO User's Guide Functional Details

(75 max)

R

Series

VDAC_F

( n Force)

VDAC_S

( n Sense)

R

(1000 max)

Load

Wire- and cable-type interconnects have some amount of associated series resistance. To calculate the total
series resistance, multiply the overall length by the manufacturer's specified resistance per unit length (Ω). If the
series resistance becomes large enough, a voltage drop error occurs along the wire when supplying current to
the load resistance. The remote sensing feature compensates for the voltage drop error that occurs along the
wire.

Connecting the USB-1608HS-2AO when using the remote sensing feature

To connect the USB-1608HS-2AO for remote sensing, connect two separate output wires—one from the
VDACn_F (force) output terminal, and one from the VDACn_S (sense) input terminal—to the high side or
positive input terminal of the field device (load). The "n" in the terminal name refers to the number of the
analog output terminal (0 or 1).

For best results, these two wires should have identical length and gauge. The use of a twisted pair is highly
recommended.

In this configuration, the sense wire detects the voltage at the end of the force wire, and compensates for the I*R
loss along the wire due to the wire resistance.

R

should not exceed the specified 1000 Ω, and the R

load

should not exceed its specified limit of 75 Ω.

series

V

compliance

= ((R

load

+ R

) * AOUT)/R

series

load

Connecting the USB-1608HS-2AO when not using the remote sensing feature

If you are not using the remote sensing feature, connect a single output wire or cable from the VDACn_F
(force) output terminal(s) to the load, and leave the VDACn_S (sense) terminals unconnected.

The voltage output range for each channel is ±10 V. The current output is a maximum of ±10 mA per channel.

Analog ground terminals

The 10 analog ground (AGND) connections provide a common ground for all analog input channels, output
channels, and the analog trigger (TRIG_IN).

Refer to the pinout diagram on page 14 for the location of the AGND terminal pins.

Digital input terminals (DI0 to DI7) and digital output terminals (DO0 to DO7)

You can connect up to eight digital input lines to screw terminals DI0 through DI7.

You can connect up to eight digital output lines to screw terminals DO0 to DO7.

Refer to the pinout diagram on page 14 for the location of these pins.

18

USB-1608HS-2AO User's Guide Functional Details

+5V EXT

GND

DI0

GND

DI0

+5V EXT

The eight input pins have 47 k resistors that you can configure to either pull-up or pull-down, or disconnected
with a jumper.

You can use the USB-1608HS-2AO digital I/O terminals to detect the state of any TTL-level input. Refer to the
switch circuit shown in Figure 8 and the schematic shown in Figure 9. If you set the switch to the +5V EXT
input, DI0 reads TRUE (1). If you move the switch to GND, DI0 reads FALSE (0).

Figure 8. Digital connection DI0 detecting the state of a switch

Figure 9. Schematic showing switch detection by digital channel DI0

Each digital input and digital output pin has an associated LED status indicator. A high at the pin lights the
LED.

You can disable the LEDs with jumpers. There is a jumper for the input LEDs, and a jumper for the output
LEDs.

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).

Power terminal (+5V EXT)

You can use the +5V EXT connection to supply power to external devices or circuitry. This terminal can output
up to 10 mA.

Refer to the pinout diagram on page 14 for the location of this pin.

Caution! The +5V EXT terminal is an output. Do not connect to an external power supply or you may

damage the USB-1608HS-2AO and possibly the computer.

Counter terminal (CTR)

The CTR terminal is a TTL-level input to a 32-bit event counter. Refer to the pinout diagram on page 14 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.

19

USB-1608HS-2AO User's Guide Functional Details

SYNC_IN pin

SYNC_OUT pin

SYNC terminals (SYNC_IN and SYNC_OUT)

You can use the SYNC_IN connection to externally pace the A/D conversions. The SYNC_IN terminal
supports TTL-level input signals of up to 250 kHz.

Use the SYNC_OUT connection to output the clock used for A/D conversions.

One example of the use of these two pins would be to synchronize with a second USB-1608HS-2AO and
acquire synchronized data from 16 channels. You can connect the SYNC_OUT pin of one USB-1608HS-2AO
to the SYNC_IN pin of another USB-1608HS-2AO to acquire data synchronously from 16 channels.

Figure 10. Configuring for synchronous data acquisition

Trigger terminal (TRIG_IN)

The TRIG_IN connection is an external analog/digital trigger input.

With the analog trigger function, you can start and control acquisitions with an analog signal. The analog trigger
threshold is from -10 V to +10 V on the TRIG_IN pin. A 12-bit DAC sets the level for the threshold. The
threshold resolution in this mode is 4.88 mV.

The USB-1608HS-2AO has three trigger options that you must set.

 Trigger above or trigger below
 Level-sensitive or edge-sensitive
 Retrigger on or retrigger off

Each trigger operation mode is explained next. In each case, a ±2 V triangle waveform is used as the TRIG_IN
input source. The high threshold is set to 1.0 V, and the low threshold signal is set to -1.0 V.

In the following analog trigger signal diagrams, the bold portion of the waveform indicates the data acquired for
the given analog trigger mode.

20

USB-1608HS-2AO User's Guide Functional Details

High threshold

Trigger can occur
anywhere in this area

Acquired data

+2

-2

0

-1

+2

-2

0

-1

Low threshold

Acquired Data

+2

-2

0

-1

+2

-2

0

-1

Trigger can occur
anywhere in this area

Trigger above, level-sensitive

The acquisition begins when the TRIG_IN signal is above the threshold level. If the TRIG_IN signal is above
the threshold at the start of the scan, the acquisition begins immediately

Figure 11. Trigger above, level-sensitive

Trigger below, level-sensitive

The acquisition begins when TRIG_IN receives a signal that is below the low threshold (-1.0 V). If the
TRIG_IN signal is below the threshold level at the start of the scan, the acquisition begins immediately

Figure 12. Trigger below, level-sensitive

21

USB-1608HS-2AO User's Guide Functional Details

Acquired data

High threshold

Trigger occurs here

+2

-2 0 -1

Low threshold

Acquired data

+2

-2 0 -1

+2

-2

0

-1

Trigger occurs here

+2

-2

0

-1

Trigger above, edge-sensitive

The acquisition begins the first time the TRIG_IN signal goes above the high threshold (1.0 V). The TRIG_IN
signal must transition from below to above the high threshold to begin the acquisition.

Figure 13. Trigger above, edge-sensitive

Trigger below, edge-sensitive

The acquisition begins when TRIG_IN signal first goes below the low threshold (-1.0 V). A transition from
above to below the threshold is necessary to begin acquisition. The TRIG_IN signal must transition from above
to below the low threshold to begin the acquisition.

Figure 14. Trigger below, edge-sensitive

22

USB-1608HS-2AO User's Guide Functional Details

Retrigger

The acquisition uses the trigger settings for positive edge/negative edge and level-sensitive/edge-sensitive, but
automatically rearms the trigger after acquiring the specified number of samples.

Common ground terminals (GND)

Three ground (GND) connections provide a common ground for the DIx, DOx, CTR, SYNC_IN and
SYNC_OUT, and +5V EXT connections.

Refer to the pinout diagram on page 14 for the location of the GND terminals.

23

Parameter

Conditions

Specification

A/D converter type

16-bit successive approximation type

Number of channels

Eight differential
Eight single-ended

Input configuration

Individual A/D per channel

Sampling method

Simultaneous

Analog input modes

Power up and reset state

CHx_H and CHx_L inputs are disconnected from their
screw terminal pins and internally connected to GND
(recommended configuration for unused inputs).

Single-ended

CHx_H inputs are connected directly to their screw
terminal pins.

CHx_L inputs are disconnected from their screw
terminal pins and internally connected to GND.

Differential

CHx_H and CHx_L inputs are connected directly to
their screw terminal pins.

Absolute maximum input
voltage

CHx IN to GND.
TRIG_IN to GND

±25 V maximum (power on)
±15 V maximum (power off)

Input impedance

CHx IN

1 GΩ (power on)

1.5 kΩ (power off)

Input bandwidth (-3 dB)

All input ranges

330 kHz

Input leakage current

±25 pA

Input capacitance

50 pf

Input ranges

Software-selectable per channel

±10 V, ±5 V, ±2 V, ±1 V

A/D pacing

Onboard A/D clock, external source (SYNC_IN). See
Table 9 on page 28.

A/D trigger source

TRIG_IN input. See Table 8 on page 27.

A/D trigger modes

External analog. See Table 8 on page 27.

Maximum working voltage
(signal + common mode)

±0.05% FSR maximum.
Sampling rate

0.009 S/s to 250 kS/s, software-programmable

Throughput

Software-paced

33 to 8000 S/s all channels, system-dependent

Scan to PC memory

250 kS/s per channel maximum (throughput rate may be
limited on USB 1.1 ports).

Resolution

16 bits

Differential non-linearity
(Note 1)

Calibrated

±2.0

Un-calibrated

± 0.5 LSB typical.
±1.0 LSB maximum.

CMRR (60 Hz)

±10 V range

81 db minimum

±5 V range

81 db minimum

±2 V range

92 db minimum

±1 V range

92 db minimum

Specifications

Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.

Analog input

Table 1. Analog input specifications

Chapter 4

24

USB-1608HS-2AO User's Guide Specifications

Range

Accuracy (mV)

±10 V

± 7.019

±5 V

± 3.509

±2 V

± 1.403

±1 V

± 0.702

Range

Integral Non Linearity
(% FSR)

Gain error at FS
(mV)

Offset (mV)

Gain tempco
(ppm/°C)

Offset tempco
(µV/°C)

±10 V

0.00915

4.578

1.526

3.8

19.5

±5 V

0.00915

2.289

0.763

7.0

19.5

±2 V

0.00915

0.916

0.305

16.5

24.3

±1 V

0.00915

0.458

0.153

40.1

29.2

Range

Peak to Peak Noise
(counts)

RMS noise
LSBrms

±10 V

8

1.21

±5 V

8

1.21

±2 V

8

1.21

±1 V

8

1.21

Note 1: The maximum differential non-linearity specification applies to the entire 0-55 °C temperature

range of the USB-1608HS-2AO. This specification also accounts for the maximum errors due to
the software calibration (in Calibrated mode only) and the AD7685 analog to digital converter
non-linearities.

Table 2. Calibrated absolute accuracy

Table 3. Accuracy components - All values are (±)

Note 2: When connecting differential inputs to floating input sources, the user must provide a DC return

path from each differential input to ground. This can be accomplished by simply connecting a
resistor from each of the differential inputs to AGND. A value of approximately 100 kΩ can be
used for most applications.

Table 4. Noise performance – all values are (±)

Table 4 summarizes the noise performance for the USB-1608HS-2AO. Noise distribution is determined by
gathering 50 kS with inputs tied to ground at the user connector. Samples are gathered at the maximum
specified sampling rate of 250 kS/s.

25

USB-1608HS-2AO User's Guide Specifications

Parameter

Conditions

Specifications

Number of channels

Two independent

Resolution

16 bits

Output range

±10 V

Throughput
Single channel

70 kS/s

Two channel

35 kS/s

Pacer source

Onboard D/A clock

Monotonicity

16 bits

Glitch energy

200 nV/s

Current output (Note 3)

±10 mA maximum single channel
±20 mA maximum two channels

Output short-circuit protection

Output connect to GND

100 mS maximum

Output coupling

DC

Power up and reset state

DACs clear to midscale, (0 V, ±20 mV).
Remote sense is disabled.

Remote sense configuration

Enabled or disabled through software
control.

Remote sense compliance voltage
(Note 4)

±10.75 V maximum

Remote sense compensation range
(Note 5)

0 to 75 Ω maximum

Output noise

100 nV/Hz

Settling time (to 0.003%)

20 V output step, (RL=5 kΩ,
CL=200 pf)

5 µS maximum

Slew rate

10 V/µs

Absolute accuracy

±0.25% of FSR maximum

Offset error drift

±4 ppm/°C

Gain error drift

±10 ppm/°C

Analog output

Table 5. Analog output specifications

Note 3: The maximum load that the analog output can drive is calculated by dividing the full-scale output

voltage by the current output specification or (10 V/10 mA) = 1000 Ω. This calculation is valid
whether the Remote Sense feature is enabled or disabled.

Note 4: The USB-1608HS-2AO Remote Sense feature can compensate for any series resistance up to

75 Ω between its force terminal pins and its output load.

Note 5: R

should not exceed the specified 1000 Ω, and the R

load

should not exceed its specified limit

series

of 75 Ω.

26

USB-1608HS-2AO User's Guide Specifications

Parameter

Specifications

Recommended warm-up time

15 minutes minimum

Calibration method

Software calibration

Calibration interval

1 year

Calibration reference

+10.000 V, ±5 mV maximum. Actual measured values stored in EEPROM

Tempco: 5 ppm/°C maximum

Long term stability: 30 ppm/1000 h

Digital type

5 V CMOS

Number of I/O

16

Configuration

Eight input, eight output

Pull-up/pull-down configuration

The eight input pins have 47 k resistors that may be configured to either pull-up
or pull-down with a jumper

Digital I/O transfer rate (system-paced)

System-dependent, 33 to 8000 port reads/writes or single bit reads/writes per
second.

Input high voltage

2.0 V minimum, 5.5 V absolute maximum

Input low voltage

0.8 V maximum, –0.5 V absolute minimum

Output high voltage (IOH = –2.5 mA)

3.8 V minimum

Output low voltage (IOL = 2.5 mA)

0.7 V maximum

Power on and reset state

Outputs: driven low

LED indicators

Each I/O pin has an associated LED status indicator. A high at the pin will
cause the LED to be on. The LEDs may be disabled with jumpers - one jumper
for the input LEDs (JP1), and one jumper for the output LEDs (JP2).

Parameter

Conditions

Specification

Trigger source

TRIG_IN input

Trigger input range

±10 V maximum.

Absolute maximum input voltage

TRIG_IN to GND

±25 V maximum (power on)
±15 V maximum (power off)

Trigger threshold levels

±10V/4096; Software configurable

Input impedance

1 MΩ (power on)

1.5 kΩ (power off)

Trigger modes

Software configurable for:

 Positive or negative slope
 Edge/level
 Retrigger

Threshold resolution

12 bits, 1 in 4096

Threshold accuracy

±0.25% FSR

Hysteresis

±5 mV

Full power bandwidth (-3 dB)

640 kHz

Analog input calibration

Table 6. Analog input calibration specifications

Digital input/output

Table 7. Digital I/O specifications

External trigger

Table 8. External trigger specifications

27

USB-1608HS-2AO User's Guide Specifications

Parameter

Conditions

Specification

Pin names

SYNC_IN, SYNC_OUT

Pin type

SYNC_IN: Input
SYNC_OUT: Output

Pin descriptions

SYNC_OUT

Outputs A/D pacer clock.

SYNC_IN

Receives A/D pacer clock from external source.
Rising edge sensitive.

Input clock rate

250 kHz maximum.

Clock pulse width
SYNC_IN

1 µs minimum

SYNC_OUT

2 µs minimum

Input leakage current

±2.0 µA

Input high voltage

3.5 V minimum, 6.5 V absolute maximum

Input low voltage

1.5 V maximum, –0.5 V absolute minimum

Output high voltage (Note 6)
IOH = –2.5 mA

3.3 V minimum

No load

3.8 V minimum

Output low voltage (Note 6)
IOL = 2.5 mA

1.1 V maximum

No load

0.6 V maximum

Pin name (Note 7)

CTR

Counter type

Event counter

Number of channels

1

Input type

TTL, rising edge triggered

Input source

CTR screw terminal

Resolution

32 bits

Schmidt trigger hysteresis

0.58 V to 0.93 V

Input leakage current

±5 µA

Maximum input frequency

1 MHz

High pulse width

500 ns minimum

Low pulse width

500 ns minimum

Input high voltage

2.4 V minimum, 6.5 V absolute maximum

Input low voltage

2.19 V maximum, –0.5 V absolute minimum

Data FIFO

65536 samples, 131,072 bytes

EEPROM

512 bytes

External clock input/output

Table 9. External clock I/O specifications

Note 6: SYNC_OUT is over-current protected with a 200 Ω series resistor.

Counter

Note 7: CTR is a Schmitt trigger input protected with a 1 kΩ series resistor.

Memory

Table 10. Counter specifications

Table 11. Memory specifications

28

USB-1608HS-2AO User's Guide Specifications

Type

High performance 8-bit RISC microcontroller

Program memory

16,384 words

Data memory

2,048 bytes

Parameter

Conditions

Specification

Supply current (see Note 8)

Continuous mode

920 mA

+5V EXT output voltage range (see Note 9)

4.5 V minimum, 5.25 V maximum

+5V EXT output current (see Note 10)

+10 mA maximum

External power input

+5.0 VDC (+5 V power supply included)

External power adapter

+5 V, ±5% @ 2 A

USB device type

USB 2.0 (high-speed)

USB device compatibility

USB 1.1, 2.0

USB cable length

Three meters maximum.

USB cable type

A-B cable, UL type AWM 2527 or equivalent (minimum 24 AWG
VBUS/GND, minimum 28 AWG D+/D-).

Operating temperature range

0 to 55 °C maximum

Storage temperature range

-40 to 85 °C maximum

Humidity

0 to 90% non-condensing

Microcontroller

Table 12. Microcontroller specifications

Power

Table 13. Power specifications

Note 8: This is the total current requirement for the USB-1608HS-2AO. This specification does not

include any additional contribution due to +5VEXT output current, analog output source current,
or DIO loading.

Note 9: Output voltage range assumes input power supply is within specified limits.
Note 10: This refers to the total amount of current that can be sourced from the +5VEXT terminal pin for

general use.

External power input

USB specifications

Environmental

Table 14. External power input specifications

Table 15. USB specifications

Table 16. Environmental specifications

29

USB-1608HS-2AO User's Guide Specifications

Card dimensions

203.2 mm (L) x 121.9 mm (W) x 20.0 mm (H)

8.0" (L) x 4.8" (W) x 0.8" (H)

Enclosure dimensions

241.3 mm (L) x 125.7 mm (W) x 58.9 mm (H)

9.50" (L) x 4.95" (W)x 2.32" (H)

Connector type

Screw terminal

Wire gauge range

16 AWG to 30 AWG

Pin

Signal name

Pin

Signal name

1

GND

28

VDAC1_F

2

DI0

29

VDAC1_S

3

DI1

30

AGND

4

DI2

31

CH0_L

5

DI3

32

CH0_H

6

DI4

33

AGND

7

DI5

34

CH1_L

8

DI6

35

CH1_H

9

DI7

36

AGND

10

GND

37

CH2_L

11

DO0

38

CH2_H

12

DO1

39

AGND

13

DO2

40

CH3_L

14

DO3

41

CH3_H

15

DO4

42

AGND

16

DO5

43

CH4_L

17

DO6

44

CH4_H

18

DO7

45

AGND

19

GND

46

CH5_L

20

SYNC_IN

47

CH5_H

21

SYNC_OUT

48

AGND

22

+5V EXT

49

CH6_L

23

CTR

50

CH6_H

24

TRIG_IN

51

AGND

25

VDAC0_F

52

CH7_L

26

VDAC0_S

53

CH7_H

27

AGND

54

AGND

Mechanical

Table 17. Mechanical specifications

Main connector and pin out

Table 18. Main connector specifications

Table 19. Main connector pin out, 8-channel differential mode

30

USB-1608HS-2AO User's Guide Specifications

Pin

Signal name

Pin

Signal name

1

GND

28

VDAC1_F

2

DI0

29

VDAC1_S

3

DI1

30

AGND

4

DI2

31

NC

5

DI3

32

CH0_H

6

DI4

33

AGND

7

DI5

34

NC

8

DI6

35

CH1_H

9

DI7

36

AGND

10

GND

37

NC

11

DO0

38

CH2_H

12

DO1

39

AGND

13

DO2

40

NC

14

DO3

41

CH3_H

15

DO4

42

AGND

16

DO5

43

NC

17

DO6

44

CH4_H

18

DO7

45

AGND

19

GND

46

NC

20

SYNC_IN

47

CH5_H

21

SYNC_OUT

48

AGND

22

+5V EXT

49

NC

23

CTR

50

CH6_H

24

TRIG_IN

51

AGND

25

VDAC0_F

52

NC

26

VDAC0_S

53

CH7_H

27

AGND

54

AGND

Table 20. Main connector pin out, 8-channel single-ended mode

31

Declaration of Conformity

Manufacturer: Measurement Computing Corporation
Address: 10 Commerce Way
Suite 1008
Norton, MA 02766
USA

Category:Electrical equipment for measurement, control and laboratory use.

Measurement Computing Corporation declares under sole responsibility that the product

USB-1608HS-2AO

EU EMC Directive 89/336/EEC: Electromagnetic Compatibility, EN 61326 (1997) Amendment 1 (1998)

Emissions: Group 1, Class A
 EN 55011 (1990)/CISPR 11: Radiated and Conducted emissions.
Immunity: EN61326, Annex A

 IEC 61000-4-2 (1995): Electrostatic Discharge immunity, Criteria A.
 IEC 61000-4-3 (1995): Radiated Electromagnetic Field immunity Criteria A.
 IEC 61000-4-4 (1995): Electric Fast Transient Burst immunity Criteria A.
 IEC 61000-4-5 (1995): Surge immunity Criteria A.
 IEC 61000-4-6 (1996): Radio Frequency Common Mode immunity Criteria A.
 IEC 61000-4-8 (1994): Power Frequency Magnetic Field immunity Criteria A.
 IEC 61000-4-11 (1994): Voltage Dip and Interrupt immunity Criteria A.

Declaration of Conformity based on tests conducted by Chomerics Test Services, Woburn, MA 01801, USA in
June, 2007. Test records are outlined in Chomerics Test Report # EMI4813.07.

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

[phone]

Fax: [phone]

E-mail: [e-mail]

www.mccdaq.com