USB-TEMP-AI
Temperature and Voltage Measurement

User's Guide

Document Revision 6A
March 2013
© Copyright 2013

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.
© 2013 Measurement Computing Corporation. All rights reserved. No part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any form by any means, electronic, mechanical, by
photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
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-TEMP-AI.docx

2

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-TEMP-AI ............................................................................................................. 6
Functional block diagram ................................................................................................................................... 7
Connecting a USB-TEMP-AI to your computer is easy ..................................................................................... 7
Chapter 2

Installing the USB-TEMP-AI ................................................................................................................. 8
What comes with your shipment? ....................................................................................................................... 8
Hardware .......................................................................................................................................................................... 8
Documentation .................................................................................................................................................................. 8

Unpacking........................................................................................................................................................... 8
Installing the software ........................................................................................................................................ 8
Installing the hardware ....................................................................................................................................... 8
Configuring the hardware ................................................................................................................................... 9
Calibrating the USB-TEMP-AI .......................................................................................................................... 9
Chapter 3

Signal I/O Connections .......................................................................................................................10
Screw terminal pinout ....................................................................................................................................... 10
Voltage input terminals (±V0H/V0L to ±V3H/V3L) .......................................................................................................10
Sensor input terminals (T0H/T0L to T3H/T3L) ...............................................................................................................11
Current excitation output terminals (±I1 and ±I2) ...........................................................................................................11
Four-wire, two sensor common terminals (4W01 and 4W23) .........................................................................................11
Sensor common terminals (IT01 and IT23) .....................................................................................................................11
Digital terminals (DIO0 to DIO7) ....................................................................................................................................11
Counter terminal (CTR) ...................................................................................................................................................11
Ground terminals (GND) .................................................................................................................................................11
Power output (+5V) .........................................................................................................................................................12
CJC sensor .......................................................................................................................................................................12

Thermocouple connections ............................................................................................................................... 12
Wiring configuration........................................................................................................................................................12

RTD and thermistor connections ...................................................................................................................... 13
Two-wire configuration ...................................................................................................................................................13
Three-wire configuration .................................................................................................................................................14
Four-wire configuration ...................................................................................................................................................14

Semiconductor sensor measurements ............................................................................................................... 15
Wiring configuration........................................................................................................................................................16

Digital I/O connections ..................................................................................................................................... 16
Configuring the DIO channels to generate alarms ...........................................................................................................16
Chapter 4

Functional Details ...............................................................................................................................17
Thermocouple measurements ........................................................................................................................... 17
Cold junction compensation (CJC) ..................................................................................................................................17
Data linearization .............................................................................................................................................................17
Open-thermocouple detection (OTD) ..............................................................................................................................17

RTD and thermistor measurements .................................................................................................................. 17
Data linearization .............................................................................................................................................................183

USB-TEMP-AI User's Guide

External components ........................................................................................................................................ 18
Screw terminals................................................................................................................................................................18
USB connector .................................................................................................................................................................18LEDs ................................................................................................................................................................................18
Chapter 5

Specifications ......................................................................................................................................19
Analog input ..................................................................................................................................................... 19
Channel configurations ..................................................................................................................................... 20
Compatible sensors: T0x-T3x ..........................................................................................................................................21

Accuracy ........................................................................................................................................................... 21
Thermocouple measurement accuracy: T0x-T3x .............................................................................................................21
Semiconductor sensor measurement accuracy: T0x-T3x .................................................................................................22
RTD measurement accuracy: T0x-T3x ............................................................................................................................22
Thermistor measurement accuracy: T0x-T3x ..................................................................................................................23
Absolute Accuracy: V0x-V3x ..........................................................................................................................................24
Settling time: V0x-V3x ....................................................................................................................................................24

Analog input calibration ................................................................................................................................... 25
Throughput rate ................................................................................................................................................ 25
Digital input/output........................................................................................................................................... 25
Counter ............................................................................................................................................................. 26
Memory ............................................................................................................................................................ 26
Microcontroller ................................................................................................................................................. 26
USB +5V voltage ............................................................................................................................................. 26
Power ................................................................................................................................................................ 27
USB specifications ........................................................................................................................................... 27
Current excitation outputs (±Ix, T0x-T3x) ....................................................................................................... 27
Environmental .................................................................................................................................................. 27
Mechanical ....................................................................................................................................................... 28
Screw terminal connector ................................................................................................................................. 28
Declaration of Conformity ..................................................................................................................29

4

Preface

About this User’s Guide
What you will learn from this user's guideThis user's guide describes the Measurement Computing USB-TEMP-AI data acquisition device and lists
device specifications.

Conventions in this user's guide
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-TEMP hardware is available on our website at www.mccdaq.com. You canalso contact Measurement Computing Corporation with specific questions.


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

5Chapter 1

Introducing the USB-TEMP-AI
The USB-TEMP-AI is a USB 2.0 full-speed, temperature measurement module that is supported under popular
Microsoft® Windows® operating systems. The USB-TEMP-AI is fully compatible with both USB 1.1 and USB
2.0 ports.
The USB-TEMP-AI provides eight analog input channels that are configured as four differential temperature
inputs and four differential or single-ended voltage inputs. A 24-bit analog-to-digital (A/D) converter isprovided for each pair of analog inputs. Eight independent, TTL-compatible digital I/O channels are provided tomonitor TTL-level inputs, communicate with external devices, and to generate alarms. The digital I/O channels
are software programmable for input or output.
The temperature input channels are configured as two channel pairs that accept temperature sensor type inputs.
You can take measurements from four sensor categories. The sensor category is software programmable foreach channel pair:

Thermocouple – types J, K, R, S, T, N, E, and B
Resistance temperature detectors (RTDs) – 2, 3, or 4-wire measurements of 100 Ω platinum RTDs
Thermistors – 2, 3, or 4-wire measurements
Semiconductor temperature sensors – LM35, TMP35 or equivalent

You can connect a different category of sensor to each temperature channel pair, but you cannot mix sensor
categories between the channels that constitute a channel pair. You can, however, mix thermocouple types
within channel pairs.
Each voltage input channel is software configurable for differential or single-ended mode. The voltage input
range is software programmable for ±10 V, ±5 V, ±2.5 V, ±1.25 V.
The USB-TEMP-AI provides a integrated cold junction compensation (CJC) sensor for thermocouple
measurements, and built-in current excitation sources for resistive sensor measurements.
An open thermocouple detection feature lets you detect a broken thermocouple. An on-board microprocessor
automatically linearizes the measurement data according to the sensor category.
The USB-TEMP-AI features eight independent temperature alarms. Each alarm controls an associated digital
I/O channel as an alarm output. The input to each alarm is one of the temperature input channels. The output ofeach alarm is software configurable as active high or low. You set up the temperature threshold conditions toactivate each alarm. When an alarm is activated, the associated DIO channel is driven to the output state.
The USB-TEMP-AI is a standalone plug-and-play module which draws power from the USB cable. No external
power supply is required. All configurable options are software programmable.
The USB-TEMP-AI is fully software calibrated.

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USB-TEMP-AI User's Guide

Introducing the USB-TEMP-AI

Functional block diagram
USB-TEMP-AI functions are illustrated in the block diagram shown here.

Figure 1. Functional block diagram

Connecting a USB-TEMP-AI to your computer is easy
Installing a data acquisition device has never been easier:









The USB-TEMP-AI relies upon the Microsoft Human Interface Device (HID) class drivers. The HID classdrivers ship with every copy of Windows that is designed to work with USB ports. We use the Microsoft
HID because it is a standard, and its performance delivers full control and maximizes data transfer rates foryour USB-TEMP-AI. No third-party device driver is required.
The USB-TEMP-AI is plug-and-play. There are no jumpers to position, DIP switches to set, or interrupts toconfigure.
You can connect the USB-TEMP-AI before or after you install the software, and without powering down
your computer first. When you connect an HID to your system, your computer automatically detects it andconfigures the necessary software. You can connect and power multiple HID peripherals to your systemusing a USB hub.
You can connect your system to various devices using a standard USB cable. The USB connector replaces
the serial and parallel port connectors with one standardized plug and port combination.
You do not need a separate power supply module. The USB automatically delivers the electrical power
required by each peripheral connected to your system.
Data can flow two ways between a computer and peripheral over USB connections.
7

Chapter 2

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

Hardware

USB-TEMP-AI
USB cable

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, you should take care while handling to avoid damage from static
electricity. Before removing the USB-TEMP-AI from its packaging, ground yourself using a wrist strap or bysimply touching the computer chassis or other grounded object to eliminate any stored static charge.
If any components are missing or damaged, contact us immediately using one of the following methods:

Knowledgebase: kb.mccdaq.com
Phone: 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
website 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
To connect the USB-TEMP-AI 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
power and communication to the USB-TEMP-AI.
When you connect the USB-TEMP-AI for the first time, a notification message opens as the USB-TEMP-AI isdetected. When the message closes, the installation is complete. The upper LED (Activity) blinks when initiallyconnected and then stays on. The lower LED (USB) turns on to indicate that communication is establishedbetween the device and computer.
If the USB LED turns off
If the LED is lit but then turns off, the computer has lost communication with the USB-TEMP-AI. To restore
communication, disconnect the USB cable from the computer, and then reconnect it. This should restore
communication, and the LED should turn back on.

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USB-TEMP-AI User's Guide

Installing the USB-TEMP-AI

Configuring the hardware
All hardware configuration options on the USB-TEMP-AI are programmable with software. Use InstaCal to set
the sensor type for each temperature channel, the range and input configuration of each voltage channel, and thealarm conditions. Any channel you don’t intend to use should be left disabled.
The configurable options dynamically update according to the selected sensor category. Configuration options
are stored on the USB-TEMP-AI 's isolated microcontroller in EEPROM, which is non-volatile memory on the
USB-TEMP-AI module. Configuration options are loaded on power up.
Default configuration
The factory default configuration is Disabled. The Disabled mode disconnects the analog inputs from theterminal blocks and internally grounds all of the A/D inputs. This mode also disables each of the current
excitation sources.

Warm up
Allow the USB-TEMP-AI to warm up for 30 minutes before taking measurements. This warm up timeminimizes thermal drift and achieves the specified rated accuracy of measurements.
For analog, RTD or thermistor measurements, this warm-up time is also required to stabilize the internal current
reference.

Calibrating the USB-TEMP-AI
The USB-TEMP-AI is fully calibrated via software. InstaCal prompts you to run its calibration utility when you
change from one sensor category to another.
Allow the USB-TEMP-AI to operate for at least 30 minutes before calibrating. This warm up time minimizes
thermal drift and achieves the specified rated accuracy of measurements.

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Chapter 3

Signal I/O Connections
Screw terminal pinout
The device screw terminals are identified in Figure 2. Between screw terminals 10 and 11 is the integrated CJC
sensor used for thermocouple measurements.

Figure 2. USB-TEMP-AI screw terminal pin numbers

Use 16 AWG to 30 AWG wire for your signal connections.
Tighten screw terminal connections
When making connections to the screw terminals, be sure to tighten the screw until tight. Simply touching the
top of the screw terminal is not sufficient to make a proper connection.

Voltage input terminals (±V0H/V0L to ±V3H/V3L)
You can connect up to four voltage inputs to the voltage channels (V0H/V0L to V3H/V3L). The input range issoftware programmable for ±10 V, ±5 V, ±2.5 V, or ±1.25 V. Each voltage channel is software configurable fordifferential or single-ended mode.
When connecting differential inputs to floating input sources, you must provide a DC return path from eachdifferential input to ground. One way to do this is to connect a resistor from one side of each of the differential
inputs to GND. A value of approximately 100 kΩ can be used for most applications.
Caution! All ground pins are common and isolated from earth ground. If a connection is made to earth
ground when using digital I/O and conductive thermocouples, the thermocouples are no longer
isolated. In this case, thermocouples must not be connected to any conductive surfaces that may bereferenced to earth ground.

10USB-TEMP-AI User's Guide

Signal I/O Connections

Sensor input terminals (T0H/T0L to T3H/T3L)
The USB-TEMP-AI supports the following temperature sensor types:
 Thermocouple – types J, K, R, S, T, N, E, and B
 Resistance temperature detectors (RTDs) – 2, 3, or 4-wire measurement modes of 100 Ω platinum RTDs.
 Thermistors – 2, 3, or 4-wire measurement modes.
 Semiconductor temperature sensors – LM35, TMP35 or equivalentSensor selection
The type of sensor you select will depend on your application needs. Review the temperature ranges andaccuracies of each sensor type to determine which is best suited for your application.
You can connect up to four temperature sensors to the differential sensor inputs (T0H/T0L to T3H/T3L).
Supported sensor categories include thermocouples, RTDs, thermistors, or semiconductor sensors.
Do not mix sensor categories within channel pairs. You can mix thermocouple types (J, K, R, S, T, N, E, and B)
within channel pairs, however.
Do not connect two different sensor categories to the same channel pair
The USB-TEMP-AI provides a 24 bit A/D converter for each channel pair. Each channel pair can monitor one
sensor category. To monitor a sensor from a different category, connect the sensor to a different pair of sensor
input terminals.

Current excitation output terminals (±I1 and ±I2)
The USB-TEMP-AI has two dedicated pairs of current excitation output terminals (±I1 and ±I2). Theseterminals have a built-in precision current source to provide excitation for the resistive sensors used for RTD
and thermistor measurements. Each current excitation terminal is dedicated to one pair of sensor input channels:

I1+ is the current excitation source, and I1- is the current excitation return for channel 0 and channel 1
I2+ is the current excitation source, and I2- is the current excitation return for channel 2 and channel 3

Four-wire, two sensor common terminals (4W01 and 4W23)
The 4W01 and 4W23 terminals are used as the common connection for four-wire configurations with two RTD
or thermistor sensors.

Sensor common terminals (IT01 and IT23)
The IT01 and IT23 terminals are used as the common connection for two-wire configurations with two RTD orthermistor sensors.

Digital terminals (DIO0 to DIO7)
You can connect up to eight digital I/O lines to the screw terminals labeled DIO0 to DIO7. Each terminal issoftware configurable for input or output.

Counter terminal (CTR)
The CTR terminal (pin 40) is the input to the 32-bit event counter. The internal counter increments when the
TTL level transitions from low to high. The counter can count events at frequencies of up to 1 MHz.
Caution! All ground pins are common and isolated from earth ground. If a connection is made to earth
ground when using digital I/O and conductive thermocouples, the thermocouples are no longer
isolated. In this case, thermocouples must not be connected to any conductive surfaces that may bereferenced to earth ground.

Ground terminals (GND)
The nine ground terminals (GND) provide a common ground for the input channels and DIO bits and are
isolated (500 VDC) from the USB GND.

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USB-TEMP-AI User's Guide

Signal I/O Connections

Power output (+5V)
The +5V output terminal is isolated (500 VDC) from the USB +5V.
Caution! The +5V terminal is an output terminal. Do not connect to an external power supply or you may
damage the USB-TEMP-AI and possibly the computer.

CJC sensor
The USB-TEMP-AI has one built-in high-resolution temperature sensor. The CJC sensor measures the ambient
temperature at the terminal block so that the cold junction voltage can be calculated.

Thermocouple connections
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junction of themetals is heated or cooled, a voltage is produced that correlates to temperature.
The USB-TEMP-AI makes fully differential thermocouple measurements without requiring ground-referencing
resistors. A 32-bit floating point value in either a voltage or temperature format is returned by software. An
open thermocouple detection (OTD) feature is available for each thermocouple input. This feature automaticallydetects an open or broken thermocouple.
Use InstaCal to select the thermocouple type (J, K, R, S, T, N, E, and B) on one or more sensor input channels
to connect the thermocouple.

Wiring configuration
Connect the thermocouple to the USB-TEMP-AI using a differential configuration, as shown in Figure 3.

Figure 3. Typical thermocouple connection

The USB-TEMP-AI GND pins are isolated from earth ground. You can connect thermocouple sensors tovoltages referenced to earth ground as long as the isolation between the GND pins and earth ground ismaintained.
When thermocouples are attached to conductive surfaces, the voltage differential between multiple
thermocouples must remain within ±1.4 V. For best results, we recommend the use of insulated or ungrounded
thermocouples when possible.
Maximum input voltage between analog input and ground
The absolute maximum input voltage between an analog input and the isolated GND pins is ±25 VDC when the
USB-TEMP-AI is powered on, and ±40 VDC when the USB-TEMP-AI is powered off.
If you need to increase the length of your thermocouple, use the same type of thermocouple wires to minimize
the error introduced by thermal EMFs.

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USB-TEMP-AI User's Guide

Signal I/O Connections

RTD and thermistor connections
A resistance temperature detector (RTD) measures temperature by correlating the resistance of the RTD
element with temperature. A thermistor is a thermally-sensitive resistor that is similar to an RTD in that its
resistance changes with temperature — thermistors show a large change in resistance that is proportional to asmall change in temperature. The main difference between RTD and thermistor measurements is the method
used to linearize the sensor data.
RTDs and thermistors are resistive devices that require an excitation current to produce a voltage drop that canbe measured differentially across the sensor. The USB-TEMP-AI features two built-in current excitation
sources (±I1 and ±I2) for measuring resistive type sensors. Each current excitation terminal is dedicated to one
channel pair.
The USB-TEMP-AI makes two, three, and four-wire measurements of RTDs (100 Ω platinum type) andthermistors.
Use InstaCal to select the sensor type and the wiring configuration. Once the resistance value is calculated, thevalue is linearized in order to convert it to a temperature value. A 32-bit floating point value in either
temperature or resistance is returned by software.
RTD maximum resistanceResistance values greater than 660 Ω cannot be measured by the USB-TEMP-AI in the RTD mode. The 660 Ω
resistance limit includes the total resistance across the current excitation (±Ix) pins, which is the sum of the
RTD resistance and the lead resistances.

Thermistor maximum resistanceResistance values greater than 180 kΩ cannot be measured by the USB-TEMP-AI in the thermistor mode. The
180 kΩ resistance limit includes the total resistance across the current excitation (±Ix) pins, which is the sum of
the thermistor resistance and the lead resistance.

Two-wire configuration
The easiest way to connect an RTD sensor or thermistor to the USB-TEMP-AI is with a two-wire configuration,
since it requires the fewest connections to the sensor. With this method, the two wires that provide the RTD
sensor with its excitation current also measure the voltage across the sensor.
Since RTDs exhibit a low nominal resistance, measurement accuracy can be affected due to the lead wire
resistance. For example, connecting lead wires that have a resistance of 1 Ω (0.5 Ω each lead) to a 100 Ω
platinum RTD will result in a 1% measurement error.
With a two-wire configuration, you can connect either one sensor per channel pair, or two sensors per channel
pair.
Two-wire, single-sensor
A two-wire single-sensor measurement configuration is shown in Figure 4.

Figure 4. Two-wire, single RTD or thermistor sensor measurement configuration

When you select a two-wire single sensor configuration with InstaCal, connections to T#H and T#L are madeinternally.
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USB-TEMP-AI User's Guide

Signal I/O Connections

Two-wire, two sensor
A two-wire, two-sensor measurement configuration is shown in Figure 5.

Figure 5. Two-wire, two RTD or thermistor sensors measurement configuration

When you select a two-wire, two sensor configuration with InstaCal, connections to T#H (first sensor) andT#H/T#L (second sensor) are made internally.
When configured for two-wire mode, both sensors must be connected to obtain proper measurements.

Three-wire configuration
A three-wire configuration compensates for lead-wire resistance by using a single voltage sense connection.
With a three-wire configuration, you can connect only one sensor per channel pair. A three-wire measurement
configuration is shown in Figure 6.

Figure 6. Three-wire RTD or thermistor sensor measurement configuration

When you select a three-wire sensor configuration with InstaCal, the USB-TEMP-AI measures the leadresistance on the first channel (T#H/T#L) and measures the sensor itself using the second channel (T#H/T#L).
This configuration compensates for any lead-wire resistance and temperature change in lead-wire resistance.
Connections to T#H for the first channel and T#H/T#L of the second channel are made internally.
Three-wire compensation
For accurate three wire compensation, the individual lead resistances connected to the ±I# pins must be of equal
resistance value.

Four-wire configuration
With a four-wire configuration, connect two sets of sense/excitation wires at each end of the RTD or thermistor
sensor. This configuration completely compensates for any lead-wire resistance and temperature change in leadwire resistance.
Connect your sensor with a four-wire configuration when your application requires very high accuracy
measurements. Examples of a four-wire single-sensor measurement configuration are shown in Figure 7 andFigure 8.
You can configure the USB-TEMP-AI with either a single sensor per channel or two sensors per channel pair.

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USB-TEMP-AI User's Guide

Signal I/O Connections

Four-wire, single-sensor
A four-wire, single-sensor connected to the first channel of a channel pair is shown in Figure 7.

Figure 7. Four-wire, single RTD or thermistor sensor measurement configuration

A four-wire, single-sensor connected to the second channel of a channel pair is shown in Figure 8.

Figure 8. Four-wire, single RTD or thermistor sensor measurement configuration

A four-wire, two-sensor measurement configuration is shown in Figure 9.

Figure 9. Four-wire, two RTD or thermistor sensors measurement configuration

When configured for four-wire, two sensor mode, both sensors must be connected to obtain proper
measurements.

Semiconductor sensor measurements
Semiconductor sensors are suitable over a range of approximately –40 C to 125 C, where an accuracy of±2 C is adequate. The temperature measurement range of a semiconductor sensor is small when compared tothermocouples and RTDs. However, semiconductor sensors can be accurate, inexpensive and easy to interface
with other electronics for display and control.
The USB-TEMP-AI makes high-resolution measurements of semiconductor sensors, and returns a 32-bit
floating point value in either voltage or temperature.
Use InstaCal to select the sensor type (LM35, TMP35 or equivalent) and the sensor input channel to connect thesensor.

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USB-TEMP-AI User's Guide

Signal I/O Connections

Wiring configuration
Connect the semiconductor sensor to the USB-TEMP-AI using a single-ended configuration, as shown in
Figure 10. The device provides +5V and GND pins for powering the sensor.

Figure 10. Semiconductor sensor measurement configuration

The software outputs the measurement data as a 32-bit floating point value in either voltage or temperature.

Digital I/O connections
You can connect up to eight digital I/O lines to the screw terminals labeled DIO0 to DIO7. You can configure
each digital bit for either input or output. All digital I/O lines are pulled up to +5V with a 47 kΩ resistor(default). You can request the factory to configure the resistor for pull-down to ground if desired.
When you configure the digital bits for input, you can use the USB-TEMP-AI digital I/O terminals to detect thestate of a TTL-compatible device. Refer to the schematic shown in Figure 11. If you set the switch to the +5V
input, DIO0 reads TRUE (1). If you move the switch to GND, DIO0 reads FALSE (0).

Figure 11. Schematic showing switch detection by digital channel DIO0

Caution! All ground pins on the USB-TEMP-AI (pins 9, 19, 22, 27, 30, 33, 36, 39, 49) are common and are
isolated from earth ground. If a connection is made to earth ground when using digital I/O andconductive thermocouples, the thermocouples are no longer isolated. In this case, thermocouples
must not be connected to any conductive surfaces that may be referenced to earth ground.
For general information regarding digital signal connections and digital I/O techniques, refer to the Guide to
DAQ Signal Connections (available on our website at www.mccdaq.com/signals/signals.pdf).

Configuring the DIO channels to generate alarms
The USB-TEMP-AI features eight independent temperature alarms. All alarm options are software
configurable.
When a digital bit is configured as an alarm, that bit will be configured as an output on the next power cycle andassume the state defined by the alarm configuration.
Each alarm controls an associated digital I/O channel as an alarm output. The input to each alarm is one of thetemperature input channels. You set up the temperature conditions to activate an alarm, and the output state of
the channel (active high or low) when activated. When an alarm is activated, its associated DIO channel isdriven to the output state specified.
The alarm configurations are stored in non-volatile memory and are loaded on power up. The temperature
alarms function both in data logging mode and while attached to the USB port on a computer.
16

Chapter 4

Functional Details
Thermocouple measurements
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junction of themetals is heated or cooled, a voltage is produced that correlates to temperature.
The USB-TEMP-AI hardware level-shifts the thermocouple’s output voltage into the A/D’s common mode
input range by applying +2.5 V to the thermocouple’s low side at the C#L input. Always connect thermocouple
sensors to the USB-TEMP-AI in a floating fashion. Do not attempt to connect the thermocouple low side C#L
to GND or to a ground referencing resistor.

Cold junction compensation (CJC)
When you connect the thermocouple sensor leads to the sensor input channel, the dissimilar metals at the USBTEMP-AI terminal blocks produce two additional thermocouple junctions. This junction creates a small voltage
error term which must be removed from the overall sensor measurement using a cold junction compensation
technique. The measured voltage includes both the thermocouple voltage and the cold junction voltage. To
compensate for the additional cold junction voltage, the USB-TEMP-AI subtracts the cold junction voltage
from the thermocouple voltage.
The USB-TEMP-AI has one high-resolution temperature sensor integrated into the design. The CJC sensor
measures the average temperature at the terminal block so that the cold junction voltage can be calculated. A
software algorithm automatically corrects for the additional thermocouples created at the terminal blocks bysubtracting the calculated cold junction voltage from the analog input's thermocouple voltage measurement.
Increasing the thermocouple length
If you need to increase the length of your thermocouple, use the same type of thermocouple wires to minimize
the error introduced by thermal EMFs.

Data linearization
After the CJC correction is performed on the measurement data, an on-board microcontroller automaticallylinearizes the thermocouple measurement data using National Institute of Standards and Technology (NIST)
linearization coefficients for the selected thermocouple type. The measurement data is then output as a 32-bit
floating point value in the configured format (voltage or temperature).

Open-thermocouple detection (OTD)
The USB-TEMP-AI is equipped with open-thermocouple detection for each analog input channel. With OTD,
any open-circuit or short-circuit condition at the thermocouple sensor is detected by the software. An open
channel is detected by driving the input voltage to a negative value outside the range of any thermocouple
output. The software recognizes this as an invalid reading and flags the appropriate channel. The software
continues to sample all channels when OTD is detected.

RTD and thermistor measurements
RTDs and thermistors are resistive devices that require an excitation current to produce a voltage drop that canbe measured differentially across the sensor. The USB-TEMP-AI measures the sensor resistance by forcing aknown excitation current through the sensor and then measuring (differentially) the voltage across the sensor todetermine its resistance.
After the voltage measurement is made, the resistance of the RTD is calculated using Ohms law – the sensor
resistance is calculated by dividing the measured voltage by the current excitation level (±Ix) source. The valueof the ±Ix source is stored in local memory.
Once the resistance value is calculated, the value is linearized in order to convert it to a temperature value. The
measurement is returned by software as a 32-bit floating point value in either temperature or resistance.
17

USB-TEMP-AI User's Guide

Functional Details

Data linearization
An on-board microcontroller automatically performs linearization on RTD and thermistor measurements.


RTD measurements are linearized using a Callendar-Van Dusen coefficients algorithm (you select DIN,
SAMA, or ITS-90).
Thermistor measurements are linearized using a Steinhart-Hart linearization algorithm (you supply thecoefficients from the sensor manufacturer's data sheet).

External components
The USB-5203 has the following external components, as shown in Figure 12.

1
2

Screw terminal pins 1 to 26
Screw terminal pins 27 to 52

3
4

LEDs: Activity (top) and Power (bottom)
USB connector

Figure 12.External component locations

Screw terminals
Use the screw terminals for connecting temperature sensors and digital I/O lines. These terminals also provide
ground and power output connections. Refer to the "Error! Reference source not found." chapter for screw
erminal descriptions.

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

LEDs
USB-TEMP-AI has two LEDs –Activity and Power.


The Activity LED (top) blinks when data is transferred.
The Power LED (bottom) turns on when the device is receiving power from the USB cable .

18

Chapter 5

Specifications
All specifications are subject to change without notice.
Typical for 25 °C unless otherwise specified.
All specifications apply to all temperature and voltage input channels unless otherwise specified.
Specifications in italic text are guaranteed by design.

Analog input
Table 1. Generic analog input specifications
Parameter

Conditions

Specification

A/D converter type

T0x to T3x, V0x toV3x

Number of channels

Voltage input; V0x toV3x

AD42_321
Dual 24-bit Sigma-Delta
4 differential, 4 single-ended

Temperature input; T0x toT3x
Input isolation
Channel configuration

T0x toT3xV0x toV3x

Analog input modes

Power up and reset state

Thermocouple; T0x toT3x

Factory default configuration is Disabled mode.
Once configured, each channel reverts to the mode
previously set by the user.
Vx_H inputs are connected directly to their screw
terminal pins.
Vx_L inputs are disconnected from their screw
terminal pins and internally connected to GND.
Vx_H and Vx_L inputs are connected directly totheir screw terminal pins.
Tx_H and Tx_L inputs are connected directly totheir screw terminal pins.
±0.080 V

RTD; T0x toT3x
Thermistor; T0x toT3x
Semiconductor sensor; T0x toT3x
Voltage; V0x toV3x

0 to 0.5 V
0 to 2 V
0 to 2.5 V±10 V, ±5 V, ±2.5 V, ±1.25 V; software selectable

T0x to T3x relative to GND(pins 9, 19, 22, 27, 30, 33, 36, 39, 49)
V0x to V3x relative to GND(pins 9, 19, 22, 27, 30, 33, 36, 39, 49)
T0x to T3x±25 V max (power on)±40 V max (power off)
±25 V max (power on)±15 V max (power off)
5 GΩ (power on)
1 MΩ (power off)
10 GΩ (power on)
2.49 kΩ (power off)
30 nA maxSingle-ended

Differential

Input ranges

Absolute maximum input
voltage

Input impedance

V0x to V3x
Input leakage current

Input bandwidth (–3 dB)

4 differential
500 VDC minimum between field wiring and USB
interfaceTemperature input.
Software programmable to match sensor type
Voltage input

T0x to T3x, with open thermocouple
detect disabled.
T0x to T3x, with open thermocouple
detect enabled.
V0x to V3x
T0x to T3x
V0x to V3x19

105 nA max±1.5 nA typ, ±25 nA max
50 Hz
3 kHz

USB-TEMP-AI User's Guide

Specifications

Parameter

Conditions

Specification

Maximum working
voltage (signal +common mode)
Common mode rejection
ratio

V0x to V3x±10.25 V max

T0x to T3x, fIN = 60 Hz
V0x to V3x, fIN = 60 Hz, all input
ranges100 dB
83 dB

ADC resolution
ADC No missing codes
Input couplingWarm-up time
Open thermocouple
detectCJC sensor accuracy

24 bits
24 bitsDC
30 minutes min
Automatically enabled when the channel pair isconfigured for thermocouple sensor.
The maximum open detection time is 3 seconds.
±0.25 °C typ, ±0.5 °C max–1.0 to +0.75 °C max

T0x to T3x

T0x to T3x, 15 °C to 35 °C
T0x to T3x, 0 °C to 70 °C

Channel configurations
Table 2. Channel configuration specifications
ChannelCategory

Conditions

Max number of
sensors (all channels
configured alike)

T0x-T3xDisabled

All temperature input channels are disconnected from screw
terminals and internally connected to GND.

See Note 4

T0x-T3x

Thermocouple(Note 1)
Semiconductor
sensor (Note 1)
RTD and
Thermistor(Note 1)

T0x-T3xT0x-T3xV0x-V3xDisabled

V0x-V3xDifferential(Note 2)Single-ended

V0x-V3x

4 differential channels
4 differential channels
2-wire input configuration with a single sensor per channelpair
2-wire input configuration with two sensors per channel pair
3-wire configuration with a single sensor per channel pair
4-wire input configuration with a single sensor per channelpair
4-wire input configuration with two sensors per channel pairAll voltage input channels are disconnected from screw
terminals and internally connected to GND.

2 differential channels
4 differential channels
2 differential channels
2 differential channels
4 differential channels
See Note 4
4 differential channels
4 single-ended channels

Note 1: Internally, the device has four, dual-channel, fully differential A/Ds providing a total of eight input

channels. The temperature input channels are configured as two channel pairs with T0x/T1x and
T2x/T3x accepting temperature sensor type inputs. This "channel-pairing" requires T0x/T1x, andT2x/T3x to be configured to monitor the same category of temperature sensor. Mixing different sensor
types of the same category (such as a type J thermocouple on temperature channel 0 and a type T
thermocouple on temperature channel 1) is valid.
Note 2: The voltage input channels V0x, V1x, V2x, and V3x are not configured as channel pairs. Therefore
each channel can be configured independently. When connecting differential inputs to floating input
sources, you must provide a DC return path from each differential input to ground. To do this, simply
connect a resistor from each of the differential inputs to GND. A value of approximately 1 MΩ can beused for most applications.

20

USB-TEMP-AI User's Guide

Specifications

Note 3: Channel configuration information is stored in the EEPROM of the isolated microcontroller by thefirmware whenever any item is modified. Modification is performed by commands issued over USB
from an external application, and the configuration is made non-volatile through the use of the
EEPROM.
Note 4: The factory default configuration is Disabled. The Disabled mode disconnects the temperature andvoltage inputs from the terminal blocks, and internally connects ground (GND) to all of the A/D
inputs. This mode also disables each of the current excitation sources.

Compatible sensors: T0x-T3xTable 3. Compatible sensor type specifications
Parameter

Conditions

Thermocouple

J: -210 °C to 1200 °C
K: -270 °C to 1372 °C
R: -50 °C to 1768 °C
S: -50 °C to 1768 °C
T: -270 °C to 400 °C
N: -270 °C to 1300 °C
E: -270 °C to 1000 °C
B: 0 °C to 1820 °C
100 Ω PT (DIN 43760: 0.00385 ohms/ohm/°C)
100 Ω PT (SAMA: 0.003911 ohms/ohm/°C)
100 Ω PT (ITS-90/IEC751:0.0038505 ohms/ohm/°C)Standard 2,252 Ω through 30,000 Ω
LM35, TMP35 or equivalent

RTD

Thermistor
Semiconductor / IC

Accuracy
Thermocouple measurement accuracy: T0x-T3xTable 4. Thermocouple accuracy specifications, including CJC measurement error. All specifications are (±).
SensorType

Sensor temperature
range (°C)

Accuracy error
maximum (°C)

Accuracy error
Typical (°C)

Tempco(°C/°C)

J

–210
0
1200
–210
0
1372
–50
250
1768
–50
250
1768
250
700
1820
–200
0
1000
–200

2.028
0.835
0.783
2.137
0.842
0.931
1.225
0.554
0.480
1.301
0.549
0.400
2.193
0.822
0.469
1.976
0.954
0.653
2.082

0.707
0.278
0.288
0.762
0.280
0.389
0.435
0.195
0.157
0.458
0.190
0.134
2.185
0.819
0.468
0.684
0.321
0.240
0.744

0.031

K

S

R

B

E

T

21

0.035

0.021

0.019

0.001

0.030

0.035

USB-TEMP-AI User's Guide

Specifications

SensorType

Sensor temperature
range (°C)

Accuracy error
maximum (°C)

Accuracy error
Typical (°C)

Tempco(°C/°C)

N

0
400
–200
0
1300

0.870
0.568
2.197
0.848
0.653

0.290
0.208
0.760
0.283
0.245

0.028

Note 5: Thermocouple measurement accuracy specifications include polynomial linearization, cold-junction

compensation and system noise. These specs are for one year, or 3000 operating hours, whichevercomes first, and for operation of the device between 15 °C and 35 °C. There is a CJC sensor on eachtemperature sensor input side of the module. The accuracy listed above assumes the screw terminals
are at the same temperature as the CJC sensor. Errors shown do not include inherent thermocouple
error. Contact your thermocouple supplier for details on the actual thermocouple accuracy error.
Note 6: Thermocouples must be connected to the device such that they are floating with respect to GND (pins9, 19, 22, 27, 30, 33, 36, 39, 49). The device GND pins are isolated from earth ground. You canconnect thermocouple sensors to voltages referenced to earth ground as long as the isolation between
the GND pins and earth ground is maintained.
Note 7: When thermocouples are attached to conductive surfaces, the voltage differential between multiple
thermocouples must remain within ±1.4 V. For best results, we recommend using insulated or
ungrounded thermocouples when possible.

Semiconductor sensor measurement accuracy: T0x-T3xTable 5. Semiconductor sensor accuracy specifications
Sensor type

Temperature Range

Accuracy Error maximum

LM35, TMP35 orequivalent–40 °C to 150 °C±0.50 °C

Note 8: Error shown does not include errors of the sensor itself. These specifications are for one year while

operation of the device is between 15 °C and 35 °C. Contact your sensor supplier for details on theactual sensor error limitations.

RTD measurement accuracy: T0x-T3xTable 6. RTD measurement accuracy specifications, Ix+ = 210 µA. All specifications are (±).
RTD

Sensor temperature
range (°C)

Accuracy error (°C)
maximum

Accuracy error (°C)
typicalTempco(°C/°C)

PT100, DIN,
US or ITS-90

–200
–150
–100
0
100
300
600

2.913
1.201
0.482
0.261
0.269
0.287
0.318

2.784
1.070
0.349
0.124
0.127
0.136
0.150

0.001
0.001
0.001
0.001
0.001
0.001
0.001

Note 9: The error shown does not include errors of the sensor itself. The sensor linearization is performed

using a Callendar-Van Dusen linearization algorithm. The accuracy and tempco specifications include
the accuracy of the Callendar-Van Dusen linearization algorithm. These specifications are for one year
while operation of the device is between 15 °C and 35 °C. The specification does not include leadresistance errors for 2-wire RTD connections. Please contact your sensor supplier for details on theactual sensor error limitations.
Note 10:
Resistance values greater than 660 Ω cannot be measured by the device in the RTD mode. The
660 Ω resistance limit includes the total resistance across the current excitation (±Ix) pins, which is thesum of the RTD resistance and the lead resistances.
22

USB-TEMP-AI User's Guide

Note 11:Specifications

For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal ohmic value. To ensure this, use connection leads of equal lengths.

Thermistor measurement accuracy: T0x-T3xTable 7. Thermistor measurement accuracy specifications, Ix+ = 10 µA. All specifications are (±)
Thermistor

Sensortemperature range

Accuracy error
maximum(°C)

Accuracy error
typical(°C)

Tempco(°C/°C)

2252 Ω

-40 °C
0 °C

0.001
0.021

0.0007
0.008

0.001
0.001

50 °C
120 °C

0.263
3.473

0.130
1.750

0.001
0.001

-35 °C
0 °C

0.001
0.009

0.0006
0.004

0.001
0.001

50 °C
120 °C

0.115
1.535

0.049
0.658

0.001
0.001

-25 °C
0 °C

0.001
0.005

0.0005
0.002

0.001
0.001

50 °C
120 °C

0.060
0.771

0.028
0.328

0.001
0.001

-10 °C
0 °C

0.001
0.002

0.0005
0.001

0.001
0.001

50 °C
120 °C

0.019
0.267

0.009
0.128

0.001
0.001

5000 Ω

10000 Ω30000 ΩNote 12:Error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Steinhart-Hart linearization algorithm. The accuracy and tempco specifications include theaccuracy of the Callendar-Van Dusen linearization algorithm. These specifications are for one year
while operation is between 15 °C and 35 °C. The specification does not include lead resistance errors
for 2-wire thermistor connections. Contact your sensor supplier for details on the actual sensor error
limitations. Total thermistor resistance on any given channel pair must not exceed 180 kΩ. Typicalresistance values at various temperatures for supported thermistors are shown in Table 8.
Table 8. Typical thermistor resistance measurement range

Temp °C

2252 Ω
thermistor

3000 Ω
thermistor

5 kΩ
thermistor

10 kΩ
thermistor

30 kΩ
thermistor

–40
–35

76 kΩ
55 kΩ

101 kΩ
73 kΩ

168 kΩ
121 kΩ

240 kΩ (Note 13)
179 kΩ

885 kΩ (Note 13)649 kΩ (Note 13)

–30
–25

40 kΩ
29 kΩ

53 kΩ
39 kΩ

88 kΩ
65 kΩ

135 kΩ
103 kΩ

481 kΩ (Note 13)
360 kΩ (Note 13)

–20
–15

22 kΩ
16 kΩ

29 kΩ
22 kΩ

49 kΩ
36 kΩ

79 kΩ
61 kΩ

271 kΩ (Note 13)
206 kΩ (Note 13)

–10
–5

12 kΩ
9.5 kΩ

17 kΩ
13 kΩ

28 kΩ
21 kΩ

48 kΩ
37 kΩ

158 kΩ
122 kΩ

0

7.4 kΩ

9.8 kΩ

16 kΩ

29 kΩ

95 kΩ

Resistance values greater than 180 kΩ cannot be measured by the device in the thermistor mode.
The 180 k Ω resistance limit includes the total resistance across the current excitation (±Ix) pins, whichis the sum of the thermistor resistance and the lead resistances.
Note 14:
For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal ohmic value. To ensure this, use connection leads of equal lengths.
Note 13:23

USB-TEMP-AI User's Guide

Specifications

Absolute Accuracy: V0x-V3xTable 9. Calibrated absolute accuracy specifications
Range

Absolute Accuracy
(mV)

±10 V
±5 V
±2.5 V±1.25 V

±2.779±1.398±0.707±0.362

When connecting differential inputs to floating input sources, the user must provide a groundreturn path from each differential input to ground. To do this, simply connect a resistor from each of
the differential inputs to GND. A value of approximately 1 M Ω can be used for most applications.
Note 16:
All ground pins are common and are isolated from earth ground. If a connection is made to earth
ground when using both voltage inputs and conductive thermocouples, the thermocouples are nolonger isolated. In this case, thermocouples must not be connected to any conductive surfaces that may
be referenced to earth ground
Note 17:
Unused voltage inputs should not be left floating. These inputs should be placed in the Disabledmode or connected to GND.
Note 15:

Table 10. Accuracy components. All values are (±)
Range

Gain error(% of reading)

Offseterror(µV)

INL error(% of range)Gain
Temperature
Coefficient(ppm/°C)

Offset Temperature
Coefficient(µV/°C)±10 V±5 V±2.5 V±1.25 V

0.02460.02460.02460.0246

16.75
16.75
16.75
16.75

0.00150.00150.00150.0015

3.68
3.68
3.68
3.68

0.42
0.42
0.42
0.42

Table 11. Noise performance specifications
Range

Peak to peak noise(µV)

RMS noise(µVrms)

Noise-Free resolution(bits)±10 V±5 V±2.5 V±1.25 V

41.13
30.85
17.14
11.14

6.23
4.67
2.60
1.69

19.09
18.51
18.36
17.98

Table 11 summarizes the noise performance for the device. Noise distribution is determined by gathering
1000 samples with inputs tied to ground at the user connector. Samples are gathered at the maximum specified
sample rate of 2 S/s.

Settling time: V0x-V3xTable 12. Settling time specifications
Range

Accuracy±0.0004%(seconds)

±10 V
±5 V
±2.5 V±1.25 V

15.0
0.40
0.40
0.40

24

USB-TEMP-AI User's Guide

Specifications

Settling time is defined as the time required for a channel to settle within a specified accuracy in response to afull-scale (FS) step input.

Analog input calibration
Table 13. Analog input calibration specifications
Parameter

Specifications

Recommended
warm-up time
Calibration
Calibration interval
Calibrationreference

30 minutes min
Firmware calibration
1 year
+10.000 V, ±5 mV max. Actual measured values stored in EEPROM
Tempco: 5 ppm/°C max
Long term stability: 30 ppm/1000 h

Throughput rate
Table 14. Throughput rate specifications
Number of Input
Channels

Maximum throughput

1
2
3
4
5
6
7
8

2 Samples/second
2 S/s on each channel, 4 S/s total
2 S/s on each channel, 6 S/s total
2 S/s on each channel, 8 S/s total
2 S/s on each channel, 10 S/s total
2 S/s on each channel, 12 S/s total
2 S/s on each channel, 14 S/s total
2 S/s on each channel, 16 S/s total

Note 18:

The analog inputs are configured to run continuously. Each channel is sampled twice per second.
The maximum latency between when a sample is acquired and the voltage/temperature data isprovided by the USB unit is approximately 0.4 seconds.

Digital input/output
Table 15. Digital input/output specifications
Parameter

Specification

Digital type
Number of I/O
Configuration

5V CMOS
8 (DIO0 through DIO7)
Independently configured for input or output.
Power on reset is input mode unless bit is configured for alarm.
All pins pulled up to +5 V via 47 K resistors (default). Contact MCC factory for
pull-down to ground (GND) capability.
 Digital input – 50 port reads or single bit reads per second typ
 Digital output – 100 port writes or single bit writes per second typ

Pull-up/pull-down
configuration
Digital I/O transfer rate
(software paced)
Input high voltage
Input low voltage
Output low voltage(IOL = 2.5 mA max)
Output high voltage(IOH = –2.5 mA max)

2.0 V min, 5.5 V absolute max
0.8 V max, –0.5 V absolute min
0.7 V max
3.8 V min25

USB-TEMP-AI User's Guide

Note 19:

Specifications

All ground pins are common and are isolated from earth ground. If a connection is made to earth
ground when using both digital I/O and conductive thermocouples, the thermocouples are no longer
isolated. In this case, thermocouples must not be connected to any conductive surfaces that may bereferenced to earth ground.

CounterTable 16. CTR I/O specifications
Parameter

Specification

Pin name
Number of channels
Resolution
Counter type
Input type
Input source
Counter read/writes rates(software paced)CTR
132-bits
Event counter
TTL, rising edge triggered
CTR screw terminal
Counter read: System dependent, 33 to 1000 reads per second.
Counter write: System dependent, 33 to 1000 reads per second.
20 mV to 100 mV±1.0 µA typ
1 MHz max
500 nS min
500 ns min
4.0 V min, 5.5 V absolute max
1.0 V max, –0.5 V absolute min

Schmidt trigger hysteresis
Input leakage current
Input frequency
High pulse width
Low pulse width
Input high voltage
Input low voltage
Note 20:

All ground pins are common and are isolated from earth ground. If a connection is made to earth
ground with both the counter (CTR) and conductive thermocouples, the thermocouples are no longer
isolated. In this case, thermocouples must not be connected to any conductive surfaces that may bereferenced to earth ground.

MemoryTable 17. Memory specifications
Parameter

Specification

EEPROM

1,024 bytes isolated micro reserved for sensor configuration
256 bytes USB micro for external application use

Microcontroller
Table 18. Microcontroller specifications
Parameter

Specification

Type

Two high-performance 8-bit RISC microcontrollers

USB +5V voltage
Table 19. USB +5V voltage specifications
Parameter

Specification

USB +5V (VBUS) input voltage
range

4.75 V min to 5.25 V max

26

USB-TEMP-AI User's Guide

Specifications

Power
Table 20. Power specifications
Parameter

Conditions

Specification

Supply current
Supply current(Note 21)
User +5V output voltage range(terminal block pin 21)
User +5V output current(terminal block pin 21)
Isolation

USB enumeration
Quiescent mode with all inputs
configured for Disabled mode<100 mA
270 mA typ

Note 21:

4.9 V min to 5.1 V max
Bus-powered and connected to aself-powered hub. (Note 21)

5 mA max

Measurement system to PC

500 VDC min

This is the total current requirement for the device which includes up to 10 mA for the status LED.

USB specifications
Table 21. USB specifications
USB device type
Device compatibility
Device power capability
USB cable type
USB cable length

USB 2.0 (full-speed)
USB 1.1, USB 2.0
Self-powered
A-B cable, UL type AWM 2725 or equivalent (min 24 AWG VBUS/GND,
min 28 AWG D+/D–)
3 meters max

Current excitation outputs (±Ix, T0x-T3x)
Table 22. Current excitation output specifications
Parameter

Specification

Configuration

2 dedicated pairs:
 ±I1: T0x/T1x
 ±I2: T2x/T3x
Thermistor: 10 µA
RTD: 210 µA±5.0%
200 ppm/°C
2.1 ppm/V max
0.3 ppm/V
3.90 V max–0.03 V min

Current excitation output
rangesTolerance
DriftLine regulation
Load regulation
Output compliance voltage(relative to GND pins)

The device has two current excitation outputs, with ±I1 dedicated to the T0x/T1x analog inputs,
and ±I2 dedicated to T2x/T3x. The excitation output currents should always be used in this dedicatedconfiguration.
Note 23:
The current excitation outputs are automatically configured based on the sensor (thermistor or
RTD) selected.
Note 22:

Environmental
Table 23. Environmental specifications
Operating temperature range
Storage temperature range
Humidity

0 °C to 55 °C max–40 °C to 85 °C max
0% to 90% non-condensing max

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USB-TEMP-AI User's Guide

Specifications

Mechanical
Table 24. Mechanical specifications
Dimensions (L × W × H)User connection length

128.52 x 88.39 × 35.56 mm (5.06 × 3.48 × 1.43 ft)
3 m (9.84 ft) max

Screw terminal connector
Table 25. Screw terminal connector specifications
Connector type
Wire gauge range

Screw terminal
16 AWG to 30 AWG
Table 26. Screw terminal pinout

Pin
1
2
3
4
5
6
7
8
9
10

Signal Name
I1+
NC
T0H
T0L
4W01
IT01
T1H
T1L
GND
I1–

Pin Description
T0/T1 current excitation source
No connection
T0 sensor input (+)
T0 sensor input (–)
T0/T1 4-wire, 2 sensor common
T0/T1 2-sensor common
T1 sensor input (+)
T1 sensor input (–)
Ground
T0/T1 current excitation return

Pin
27
28
29
30
31
32
33
34
35
36

Signal Name
GND
V3L
V3H
GND
V2L
V2H
GND
V1L
V1H
GND

Pin Description
GroundV3 voltage input (–)
V3 voltage input (+)
GroundV2 voltage input (–)
V2 voltage input (+)
Ground
V1 voltage input (–)
V1 voltage input (+)
GroundT2/T3 current excitation source

37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52

V0L
V0H
GND
CTR
DIO7
DIO6
DIO5
DIO4
DIO3
DIO2
DIO1
DIO0
GND
NC
NC
NC

V0 voltage input (–)
V0 voltage input (+)
GroundCounter Input
DIO channel 7
DIO channel 6
DIO channel 5
DIO channel 4
DIO channel 3
DIO channel 2
DIO channel 1
DIO channel 0
GroundNo connection
No connection
No connection

CJC sensor
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

I2+
NC
T2H
T2L
4W23
IT23
T3H
T3L
GND
I2–
+5V
GND
NC
NC
NC
NC

T2 sensor input (+)
T2 sensor input (–)
T2/T3 4-wire, 2 sensor common
T2/T3 2 sensor common
T3 sensor input (+)
T3 sensor input (–)
GroundT2/T3 current excitation return+5V output
GroundNo connection
No connection
No connection
No connection28

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 product

USB-TEMP-AI
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 C.
IEC 61000-4-3 (1995): Radiated Electromagnetic Field immunity Criteria A.
IEC 61000-4-8 (1994): Power frequency magnetic field immunity Criteria A.

Declaration of Conformity based on tests conducted by Chomerics Test Services, Woburn, MA 01801, USA in
July, 2007. Test records are outlined in Chomerics Test Report #EMI4833.07.
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(508) 946-5100
Fax: (508) 946-9500
E-mail: info@mccdaq.com
www.mccdaq.com