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OM-USB-5203
8 Channel Temperature
Measurement
USB Data Acquisition
Module/Data Logger
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Servicing North America:
U.S.A.: Omega Engineering, Inc., One Omega Drive, P.O. Box 4047
ISO 9001 Certified Stamford, CT 06907-0047 USA
Canada: 976 Bergar
Laval (Quebec), H7L 5A1 Canada
Toll-Free: 1-800-826-6342 TEL: (514) 856-6928
FAX: (514) 856-6886 e-mail: [email protected]
For immediate technical or application assistance:
U.S.A. and Canada: Sales Service: 1-800-826-6342/1-800-TC-OMEGA
®
Customer Service: 1-800-622-2378/1-800-622-BEST
®
Engineering Service: 1-800-872-9436/1-800-USA-WHEN
®
Mexico/ En Español: 001 (203) 359-7803 FAX: 001 (203) 359-7807
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Benelux: Managed by the United Kingdom Office
Czech Republic: Frystatska 184
733 01 Karviná, Czech Republic
Toll-Free: 0800-1-66342 TEL: +420-59-6311899
FAX: +420-59-6311114 e-mail: [email protected]
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Toll-Free: 0800 6397678 TEL: +49 (0) 7056 9398-0
FAX: +49 (0) 7056 9398-29 e-mail: [email protected]
United Kingdom: OMEGA Engineering Ltd.
ISO 9001 Certified One Omega Drive, River Bend Technology Centre, Northbank
Irlam, Manchester M44 5BD United Kingdom
Toll-Free: 0800-488-488 TEL: +44 (0) 161 777-6611
FAX: +44 (0) 161 777-6622 e-mail: [email protected]
OMEGAnet®Online Service Internet e-mail
omega.com [email protected]
It is the policy of OMEGA Engineering, Inc. to comply with all worldwide safety and EMC/EMI
regulations that apply. OMEGA is constantly pursuing certification of its products to the European New
Approach Directives. OMEGA will add the CE mark to every appropriate device upon certification.
The information contained in this document is believed to be correct, but OMEGA accepts no liability for any
errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, human applications.
Page 3
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 OM-USB-5203 .................................................................................................................. 6
Overview: OM-USB-5203 features.......................................................................................................................... 6
Logging data with the OM-USB-5203 ......................................................................................................................................7
OM-USB-5203 block diagram.................................................................................................................................. 7
Software features ....................................................................................................................................................... 7
Connecting a OM-USB-5203 to your computer is easy .......................................................................................... 8
Chapter 2
Installing the OM-USB-5203 ...................................................................................................................... 9
What comes with your OM-USB-5203 shipment? .................................................................................................. 9
Hardware.....................................................................................................................................................................................9
Additional documentation ..........................................................................................................................................................9
Unpacking the OM-USB-5203 ............................................................................................................................... 10
Installing the software ............................................................................................................................................. 10
Installing the hardware ............................................................................................................................................ 10
Configuring the OM-USB-5203 ............................................................................................................................. 10
Configuring data logging options.............................................................................................................................................11
Calibrating the OM-USB-5203............................................................................................................................... 11
Chapter 3
Sensor Connections................................................................................................................................. 12
Screw terminal pin out ............................................................................................................................................ 12
Sensor input terminals (C0H/C0L to C7H/C7L).....................................................................................................................13
Current excitation output terminals (±I1 to ±I4) .....................................................................................................................14
Four-wire, two sensor common terminals (4W01 to 4W67) ..................................................................................................14
Two sensor common terminals (IC01 to IC67).......................................................................................................................14
Ground terminals (GND)..........................................................................................................................................................14
Power terminals (+5V) ................................................................
.............................................................................................14
Digital terminals (DIO0 to DIO7)............................................................................................................................................14
CJC sensors...............................................................................................................................................................................14
Thermocouple connections ..................................................................................................................................... 14
Wiring configuration ................................................................................................................................................................15
RTD and thermistor connections ............................................................................................................................ 15
Two-wire configuration............................................................................................................................................................16
Three-wire configuration..........................................................................................................................................................17
Four-wire configuration............................................................................................................................................................17
Semiconductor sensor measurements ..................................................................................................................... 18
Wiring configuration ................................................................................................................................................................18
Digital I/O connections ........................................................................................................................................... 19
Configuring the DIO channels to generate alarms ..................................................................................................................19
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OM-USB-5203 User's Guide
Chapter 4
Functional Details ..................................................................................................................................... 20
Thermocouple measurements ................................................................................................................................. 20
Cold junction compensation (CJC)..........................................................................................................................................20
Data linearization......................................................................................................................................................................20
Open-thermocouple detection (OTD) ......................................................................................................................................20
RTD and thermistor measurements ........................................................................................................................ 21
Data linearization......................................................................................................................................................................21
External components ............................................................................................................................................... 21
Screw terminals.........................................................................................................................................................................22
USB connector..........................................................................................................................................................................22
LED .......................................................................................................
CompactFlash
Data logging button ..................................................................................................................................................................23
®
memory card slot............................................................................................................................................23
....................................................................................22
External power supply............................................................................................................................................. 23
Disconnecting the OM-USB-5203 from the computer .......................................................................................... 23
Transferring binary data after a logging session .................................................................................................... 23
Converting binary data after a logging session .....................................................................
Chapter 5
................................. 24
Specifications............................................................................................................................................ 25
Analog input section................................................................................................................................................ 25
Channel configurations .....................................................................
...................................................................... 26
Compatible sensors.................................................................................................................................................. 26
Accuracy .................................................................................................................................................................. 27
Thermocouple measurement accuracy.....................................................................................................................................27
Semiconductor sensor measurement accuracy ........................................................................................................................27
RTD measurement accuracy ....................................................................................................................................................28
Thermistor measurement accuracy .........
.................................................................................................................................28
Throughput rate to PC ............................................................................................................................................. 29
Digital input/output ..............................................................................................................................
................... 30
Temperature alarms................................................................................................................................................. 30
Memory.................................................................................................................................................................... 30
Microcontroller..................................................................
...................................................................................... 30
Data Logging ........................................................................................................................................................... 31
Real time clock ........................................................................................................................................................ 32
USB +5V voltage .
................................................................................................................................................... 32
Power ....................................................................................................................................................................... 32
USB specifications ..................................................................................
................................................................ 33
Current excitation outputs (Ix+).............................................................................................................................. 33
Environmental ......................................................................................................................................................... 33
Mechanical...................................................
............................................................................................................ 33
Screw terminal connector type and pin out ............................................................................................................ 34
Screw terminal pin out..............................................................................................................................................................34
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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 OM-USB-5203 so that you get the most out of
its temperature measurement and data logging 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:
Never touch the exposed pins or circuit connections on the board.
Where to find more information
For additional information relevant to the operation of your hardware, refer to the Documents subdirectory
where you installed the software, or search for your device on our website at www.omega.com.
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Chapter 1
Introducing the OM-USB-5203
Overview: OM-USB-5203 features
This user's guide contains all of the information you need to connect the OM-USB-5203 to your computer and
to the signals you want to measure.
The OM-USB-5203 is a USB 2.0 full-speed, temperature measurement device that is supported under popular
Microsoft
®
Windows® operating systems. The OM-USB-5203 is fully compatible with both USB 1.1 and USB
2.0 ports.
The OM-USB-5203 provides eight differential input channels that are software-programmable for different
sensor categories including thermocouple, RTDs, thermistors and semiconductor sensors.
Eight independent, TTL-compatible digital I/O channels are provided to monitor TTL-level inputs,
communicate with external devices, and to generate alarms. The digital I/O channels are software-
programmable for input or output.
With the OM-USB-5203, you can take measurements from four sensor categories:
Thermocouple – types J, K, R, S, T, N, E, and B
Resistance temperature detectors (RTDs) – 2, 3, or 4-wire measurements of 100 _ platinum RTDs
Thermistors – 2, 3, or 4-wire measurements
Semiconductor temperature sensors – LM36 or equivalent
The OM-USB-5203 provides a 24-bit analog-to-digital (A/D) converter for each pair of differential analog input
channels. Each pair of differential inputs constitutes a channel pair.
You can connect a different category of sensor to each channel pair, but you cannot mix categories among the
channels that constitute a channel pair (although it is permissible to mix thermocouple types).
The OM-USB-5203 provides two integrated cold junction compensation (CJC) sensors 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 OM-USB-5203 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 of
each alarm is software configurable as active high or low. You set up the temperature threshold conditions to
activate each alarm. When an alarm is activated, the associated DIO channel is driven to the output state.
You can log your sensor measurements to a CompactFlash
®
memory card. CompactFlash is a removable nonvolatile storage device. A 512!MB CompactFlash memory card is shipped with the device to store your data.
For more information, refer to the section "Logging data with the OM-USB-5203" on page 7.
External power is required for data logging operations
Due to processing limitations, data logging to the memory card is not allowed when the OM-USB-5203 is
connected to your computer's active USB bus. When operating as a data logger, disconnect the USB cable from
the computer, and connect the external power supply shipped with the device.
The OM-USB-5203 is a standalone plug-and-play device. External power is required for data logging mode
only. All configurable options are software programmable. The OM-USB-5203 is fully software calibrated.
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OM-USB-5203 User's Guide Introducing the OM-USB-5203
Logging data with the OM-USB-5203
The OM-USB-5203 has many software-configurable options for setting up data logging.
You can record:
temperature (° C) or raw data from selected input channels
timestamp data
CJC sensor readings
You can also specify the number of seconds between samples. You can begin logging data at power up, when
you press the data logging button, or at a specific date and time.
OM-USB-5203 block diagram
OM-USB-5203 functions are illustrated in the block diagram shown here.
Figure 1. OM-USB-5203 functional block diagram
Software features
For information on the features of InstaCal and the other software included with your OM-USB-5203, refer to
the OMB-DAQ-2416 Series and OM-USB Series Data Acquisition Software User’s Guide that shipped with
your device.
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OM-USB-5203 User's Guide Introducing the OM-USB-5203
Connecting a OM-USB-5203 to your computer is easy
Installing a data acquisition device has never been easier.
The OM-USB-5203 relies upon the Microsoft Human Interface Device (HID) class drivers. The HID class
drivers 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 for
your OM-USB-5203. No third-party device driver is required.
In addition to utilizing the HID class drivers, the OM-USB-5203 also utilizes the Mass Storage Device
interface to allow the CompactFlash Card adapter to appear as a storage device. This feature allows direct
access to data files stored on the OM-USB-5203.
The OM-USB-5203 is plug-and-play. There are no jumpers to position, DIP switches to set, or interrupts to
configure.
You can connect the OM-USB-5203 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 and
configures the necessary software. You can connect and power multiple HID peripherals to your system
using a USB hub.
You can connect your system to various devices using a standard four-wire 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 device for normal operation. The USB automatically delivers the
electrical power required by each peripheral connected to your system. However, for data logging
operations, an external power supply is required.
Data can flow two ways between a computer and peripheral over USB connections.
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Installing the OM-USB-5203
What comes with your OM-USB-5203 shipment?
The following items are shipped with the OM-USB-5203.
Hardware
The following items should be included with your shipment.
OM-USB-5203 with memory card
Chapter 2
USB cable (2 meter length)
External power supply – 2.5 watt USB adapter for data logging operations.
Omega part number USB Power Adapter.
Additional documentation
In addition to this hardware user's guide, you should also receive the OMB-DAQ-2416 Series and OM-USB
Series Data Acquisition Software User’s Guide). This booklet supplies a brief description of the software you
received with your OM-USB-5203 and information regarding installation of that software. Please read this
booklet completely before installing any software or hardware.
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OM-USB-5203 User's Guide Installing the OM-USB-5203
Unpacking the OM-USB-5203
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the OM-USB-5203 from its packaging, ground yourself using a wrist strap or by
simply touching the computer chassis or other grounded object to eliminate any stored static charge.
If any components are missing or damaged, notify Omega Engineering immediately by phone, fax, or e-mail.
Installing the software
Refer to the OMB-DAQ-2416 Series and OM-USB Series Data Acquisition Software User’s Guide for
instructions on installing the software on the OMB-DAQ-2416 Series and OM-USB Series Data Acquisition
Software CD. This booklet is available in PDF at http://omega.com/manuals.
Installing the hardware
To connect the OM-USB-5203 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 OM-USB-5203.
Caution! If you are connecting the OM-USB-5203 to an external self-powered hub, connect the USB hub to
the computer before you connect the device to the hub. This ensures that the device detects the hub
as an active USB port.
The OM-USB-5203 installs as a composite device with separate devices attached. When you connect the OMUSB-5203 for the first time,
version) open as each OM-USB-5203 interface is detected.
It is normal for multiple dialogs to open when you connect the OM-USB-5203 for the first time. For additional
information, refer to the "Notes on installing and using the OM-USB-5201 and OM-USB-5203 data logging
devices" that shipped with the OM-USB-5203.
When the last balloon or dialog closes, the installation is complete. The LED on the OM-USB-5203 should
flash and then remain lit. This indicates that communication is established between the OM-USB-5203 and your
computer.
Caution! Do not disconnect any device from the USB bus while the computer is communicating with the
OM-USB-5203, or you may lose data and/or your ability to communicate with the OM-USB-
5203.
If the LED turns off
If the LED is lit but then turns off, the computer has lost communication with the OM-USB-5203. 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.
Found New Hardware popup balloons (Windows XP) or dialogs (other Windows
Configuring the OM-USB-5203
All hardware configuration options on the OM-USB-5203 are programmable with software. Use InstaCal to set
the sensor type for each channel.
The configurable options dynamically update according to the selected sensor category. Configuration options
are stored on the OM-USB-5203 's isolated microcontroller in EEPROM, which is non-volatile memory on the
OM-USB-5203 device. Configuration options are loaded on power up.
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OM-USB-5203 User's Guide Installing the OM-USB-5203
Default configuration
The factory default sensor type configuration is Disabled. The disabled mode disconnects the analog inputs
from the terminal blocks and internally grounds all of the A/D inputs. This mode also disables each of the
current excitation sources.
Warm up
Allow the OM-USB-5203 to warm up for 30 minutes before taking measurements. This warm up time
minimizes thermal drift and achieves the specified rated accuracy of measurements.
For RTD or thermistor measurements, this warm-up time is also required to stabilize the internal current
reference.
Configuring data logging options
The following data logging options are programmable with InstaCal.
select the input channels to log
set the data format
set the start mode
set up alarm conditions
copy and convert saved binary files
delete data files
All data logging options are stored on the OM-USB-5203 in non-volatile memory in EEPROM, and are loaded
on power up.
Calibrating the OM-USB-5203
The OM-USB-5203 is fully calibrated with InstaCal. Calibration coefficients are stored in EEPROM. InstaCal
prompts you to run its calibration utility when you change from one sensor category to another.
Allow the OM-USB-5203 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
Sensor Connections
The OM-USB-5203 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 _ platinum RTDs.
Thermistors – 2, 3, or 4-wire measurement modes.
Semiconductor temperature sensors – LM36 or equivalent
Sensor selection
The type of sensor you select will depend on your application needs. Review the temperature ranges and
accuracies of each sensor type to determine which is best suited for your application.
Screw terminal pin out
The OM-USB-5203 has four rows of screw terminals — two rows on the top edge of the housing, and two rows
on the bottom edge. Each row has 26!connections. Between each bank of screw terminals are two integrated
CJC sensors used for thermocouple measurements. Signals are identified in Figure 2.
Figure 2. OM-USB-5203 screw terminal pin numbers
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OM-USB-5203 User's Guide Sensor Connections
OM-USB-5203 screw terminal descriptions
Pin Signal Name Pin Description Pin Signal Name Pin Description
1 I1+ CH0/CH1 current excitation source 27 I4- CH6/CH7 current excitation return
2 NC Not connected 28 GND Ground
3 C0H CH0 sensor input (+) 29 C7L CH7 sensor input (-)
4 C0L CH0 sensor input (-) 30 C7H CH7 sensor input (+)
5 4W01 CH0/CH1 4-wire, 2 sensor common 31 IC67 CH6/CH7 2 sensor common
6 IC01 CH0/CH1 2-sensor common 32 4W67 CH6/CH7 4-wire, 2 sensor common
7 C1H CH1 sensor input (+) 33 C6L CH6 sensor input (-)
8 C1L CH1 sensor input (-) 34 C6H CH6 sensor input (+)
9 GND Ground 35 NC Not connected
10 I1- CH0/CH1 current excitation return 36 I4+ CH6/CH7 current excitation source
CJC sensor CJC sensor
11 I2+ CH2/CH3 current excitation source 37 I3- CH4/CH5 current excitation return
12 NC Not connected 38 GND Ground
13 C2H CH2 sensor input (+) 39 C5L CH5 sensor input (-)
14 C2L CH2 sensor input (-) 40 C5H CH5 sensor input (+)
15 4W23 CH2/CH3 4-wire, 2 sensor common 41 IC45 CH4/CH5 2 sensor common
16 IC23 CH2/CH3 2 sensor common 42 4W45 CH4/CH5 4-wire, 2 sensor common
17 C3H CH3 sensor input (+) 43 C4L CH4 sensor input (-)
18 C3L CH3 sensor input (-) 44 C4H CH4 sensor input (+)
19 GND Ground 45 NC Not connected
20 I2- CH2/CH3 current excitation return 46 I3+ CH4/CH5 current excitation source
21 +5V +5V output 47 +5V +5V output
22 GND Ground 48 GND Ground
23 DIO0 Digital Input/output 49 DIO7 Digital Input/output
24 DIO1 Digital Input/output 50 DIO6 Digital Input/output
25 DIO2 Digital Input/output 51 DIO5 Digital Input/output
26 DIO3 Digital Input/output 52 DIO4 Digital Input/output
Use 16 AWG to 30 AWG wire for your signal connections.
Tighten screw terminal connections
When making connections to the screw terminals, fully tighten the screw. Simply touching the top of the screw
terminal is not sufficient to make a proper connection.
Sensor input terminals (C0H/C0L to C7H/C7L)
You can connect up to eight temperature sensors to the differential sensor inputs (C0H/C0L to C7H/C7L).
Supported sensor categories include thermocouples, RTDs, thermistors, or semiconductor sensors.
Do not mix sensor categories within channel pairs. It is permitted to 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 OM-USB-5203 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 channel pair
(input terminals).
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OM-USB-5203 User's Guide Sensor Connections
Current excitation output terminals (±I1 to ±I4)
The OM-USB-5203 has four dedicated pairs of current excitation output terminals (±I1 to ±I4). These terminals
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 for channel 0 and channel 1
I2+ is the current excitation source for channel 2 and channel 3
I3+ is the current excitation source for channel 4 and channel 5
I4+ is the current excitation source for channel 6 and channel 7
Four-wire, two sensor common terminals (4W01 to 4W67)
These terminals are used as the common connection for four-wire configurations with two RTD or thermistor
sensors.
Two sensor common terminals (IC01 to IC67)
These terminals are used as the common connection for two-wire configurations with two RTD or thermistor
sensors.
Ground terminals (GND)
The six ground terminals (GND) provide a common ground for the input channels and DIO bits and are isolated
(500 VDC) from the USB GND.
Power terminals (+5V)
The two +5V output terminals are isolated (500 VDC) from the USB +5V.
Caution! Each +5V terminal is an output. Do not connect to an external power supply to these terminals or
you may damage the OM-USB-5203 and possibly the computer.
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 is
software-configurable for input or output.
If a digital bit is set up as an alarm, the bit is configured for output on power-up, and assumes the state defined
by the alarm configuration.
CJC sensors
The OM-USB-5203 has two built in high-resolution temperature sensors. One sensor is located on the right side
of the package, and one sensor is located on the left side.
Thermocouple connections
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junction of the
metals is heated or cooled, a voltage is produced that correlates to temperature.
The OM-USB-5203 makes fully-differential thermocouple measurements without the need of groundreferencing resistors. A 32-bit floating point value in either a voltage or temperature format is returned by
software. An open thermocouple detection feature is available for each analog input which automatically detects
an open or broken thermocouple.
Use InstaCal to select the thermocouple type (J, K, R, S, T, N, E, and B) and one or more sensor input channels
to connect the thermocouple.
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OM-USB-5203 User's Guide Sensor Connections
Wiring configuration
Connect the thermocouple to the OM-USB-5203 using a differential configuration, as shown in Figure 3.
Figure 3. Typical thermocouple connection
The OM-USB-5203 GND pins are isolated from earth ground, so connecting thermocouple sensors to voltages
referenced to earth ground is permissible as long as the isolation between the GND pins (9, 19, 28, 38) and earth
ground is maintained.
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
OM-USB-5203 is powered on, and ±40 VDC when the OM-USB-5203 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.
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 a
small 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 can
be measured differentially across the sensor. The OM-USB-5203 features four built-in current excitation
sources (±I1 to ±I4) for measuring resistive type sensors. Each current excitation terminal is dedicated to one
channel pair.
The OM-USB-5203 makes two, three, and four-wire measurements of RTDs (100 _ platinum type) and
thermistors.
Use InstaCal to select the sensor type and the wiring configuration. Once the resistance value is calculated, the
value 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 resistance
Resistance values greater than 660 Ω cannot be measured by the OM-USB-5203 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.
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OM-USB-5203 User's Guide Sensor Connections
Thermistor maximum resistance
Resistance values greater than 180 kΩ cannot be measured by the OM-USB-5203 in the thermistor mode. The
180 k Ω 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 OM-USB-5203 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 C#H and C#L are made
internally.
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 C#H (first sensor) and
C#H/C#L (second sensor) are made internally.
When configured for two-wire mode, both sensors must be connected to obtain proper measurements.
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OM-USB-5203 User's Guide Sensor Connections
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 OM-USB-5203 measures the lead
resistance on the first channel (C#H/C#L) and measures the sensor itself using the second channel (C#H/C#L).
This configuration compensates for any lead-wire resistance and temperature change in lead-wire resistance.
Connections to C#H for the first channel and C#H/C#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 and
Figure 8.
You can configure the OM-USB-5203 with either a single-sensor-per-channel, or a two-sensor–per-channel
pair.
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.
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OM-USB-5203 User's Guide Sensor Connections
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 two-wire 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 to
thermocouples and RTDs. However, semiconductor sensors can be accurate, inexpensive, and easy to interface
with other electronics for display and control.
The OM-USB-5203 makes high-resolution measurements of semiconductor sensors, such as the LM36 or
equivalent, and returns a 32-bit floating point value in either a voltage or temperature format.
Use InstaCal to select the sensor type (TMP36 or equivalent) and the sensor input channel to connect the
sensor.
Wiring configuration
You can connect a TMP36 (or equivalent) semiconductor sensor to the OM-USB-5203 using a single-ended
configuration, as shown in Figure 10. The OM-USB-5203 also provides
sensor.
+5V and GND pins for powering the
Figure 10. Semiconductor sensor measurement configuration
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OM-USB-5203 User's Guide Sensor Connections
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. 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. You can configure each digital bit for either input or output.
Caution! If a digital bit is set up as an alarm, the bit will be configured for output on power-up, and assume
the state defined by the alarm configuration.
When you configure the digital bits for input, you can use the OM-USB-5203 digital I/O terminals to detect the
state of any TTL-level input. 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 OM-USB-5203 (pins 9, 19, 28, 38) are common and are 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 be referenced to earth ground.
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 http://www.omega.com/manuals/manualpdf/M4830.pdf).
Configuring the DIO channels to generate alarms
The OM-USB-5203 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 and
assume 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 the
temperature 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 is
driven 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.
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Chapter 4
Functional Details
Thermocouple measurements
A thermocouple consists of two dissimilar metals that are joined together at one end. When the junction of the
metals is heated or cooled, a voltage is produced that correlates to temperature.
The OM-USB-5203 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 OM-USB-5203 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 OMUSB-5203 terminal blocks produce an additional thermocouple junction. 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 OM-USB-5203 subtracts the cold junction voltage from
the thermocouple voltage.
The OM-USB-5203 has two high-resolution temperature sensors that are integrated into the design of the OMUSB-5203. One sensor is located on the right side of the package, and one sensor is located at the left side. The
CJC sensors measure the average temperature at the terminal blocks so that the cold junction voltage can be
calculated. A software algorithm automatically corrects for the additional thermocouples created at the terminal
blocks by subtracting 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 automatically
linearizes 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 OM-USB-5203 is equipped with an 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.
Input leakage current
With open-thermocouple detection enabled, 105 nA (max.) of input leakage current is injected into the
thermocouple. This current can cause an error voltage to develop across the lead resistance of the thermocouple
that is indistinguishable from the thermocouple voltage you are measuring. You can estimate this error voltage
with the following formula:
error voltage = resistance of the thermocouple x 105 nA
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OM-USB-5203 User's Guide Functional Details
To reduce the error, reduce the length of the thermocouple to lower its resistance, or lower the AWG of the wire
by using a wire with a larger diameter. With open-thermocouple detection disabled, 30 nA (max) of input
leakage current is injected into the thermocouple.
RTD and thermistor measurements
RTDs and thermistors are resistive devices that require an excitation current to produce a voltage drop that can
be measured differentially across the sensor. The OM-USB-5203 measures the sensor resistance by forcing a
known excitation current through the sensor and then measuring (differentially) the voltage across the sensor to
determine 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 (±
of the ±
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 a voltage, resistance or temperature
format.
Ix source is stored in local memory.
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 the
coefficients from the sensor manufacturer's data sheet).
Ix) source. The value
External components
The OM-USB-5203 has the following external components, as shown in Figure 12.
Screw terminals
USB connector
LED
CompactFlash slot with memory card
Figure 12. OM-USB-5203 component locations
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OM-USB-5203 User's Guide Functional Details
Screw terminals
The device's four banks of screw terminals are for connecting temperature sensors and digital I/O lines. These
terminals also provide ground and power output connections. Refer to the "Sensor Connections" chapter for
screw terminal descriptions.
USB connector
When not logging data, connect the USB cable to a USB port on your computer or to an external USB hub that
is connected to your computer. When connected to an active USB bus, the device's USB connector provides
+5 V power and communication. The voltage supplied through the USB connector is system-dependent, and
may be less than 5 V. No external power supply is required.
Due to processing limitations, you cannot log data when the device is attached to an active USB bus. For data
logging operations, connect the device's USB connector to the external power supply.
LED
The LED uses up to 5 mA of current. The function of the LED varies according to whether the OM-USB-5203
is connected to an active USB port, or when the device is logging data and connected to the external power
supply.
The table below lists the function of the LED when the device is connected to an active USB port and not
logging data.
LED function when the OM-USB-5203 is connected to an active USB port
LED Illumination Indication
Steady green The OM-USB-5203 is connected to a computer or external USB hub.
Blinks continuously Data is being transferred.
Upon connection, the LED should flash a few times and then remain lit (indicates a successful
installation).
Blinks several times Initial communication is established between the OM-USB-5203 and the computer.
Off The OM-USB-5203 is not connected to an active USB port.
The table below lists the function of the LED when the device is connected to the external supply and is logging
data. The function of the LED varies according to the selected logging mode.
LED function when the OM-USB-5203 is logging data
Logging mode LED Illumination Indication
Logging off
Start Logging on Power
Up
Start Logging on Button
Start Logging at
Specified Time
Any logging mode Blinks rapidly (250 ms period) and continuously. The memory card is full.
The LED is off. The OM-USB-5203 is not logging data,
and/or the device is not powered
The LED turns on when external power is
connected, then blinks each time data is captured.
The LED stays off until the data logging button is
pressed and held for approximately 1 second. At
that time, the LED turns on and blinks each time
data is captured.
The LED is off – blinks on once per second until
the specified date/time to start logging is reached.
At that time, the LED turns on – blinks off each
time data is captured.
Blinks when logging data.
Blinks when logging data.
Blinks on once per second until specified
data/time to log data occurs. Then it turns
on and blinks each time data is captured.
The memory card was removed during
logging. Insert the memory card again
to stop the device blinking.
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OM-USB-5203 User's Guide Functional Details
CompactFlash® memory card slot
The CompactFlash slot accepts standard memory cards. A 512 MB memory card is shipped with the device. For
extensive data logging, you can insert a higher capacity card of up to 2 GB. You must format the memory card
before logging data for the first time.
Data logging button
The data logging button is used to end a data logging session. The data logging button is also used to start
recording data when the logging mode is set in InstaCal to Start Logging on Button.
To begin recording data, press and hold the button until the LED begins to blink. The first sample is taken
one second after the LED illuminates.
When you first power on the OM-USB-5203, wait at least five seconds before pressing the data logging
button. To achieve rated accuracy, allow the OM-USB-5203 to warm up for 30 minutes before logging
data.
To stop recording data, press and hold the button again until the LED is off.
Caution! To prevent loss of data, always use the button to stop logging. Make sure the data is written to the
memory card before you disconnect the device from the power source.
The device caches log data in volatile memory prior to writing to the memory card.
Pressing the data logging button has no effect when the OM-USB-5203 is connected to an active USB port and
not logging data.
External power required for data logging
Due to processing limitations, data logging is not allowed when the OM-USB-5203 is attached to an active USB
bus. The OM-USB-5203 must be connected to the standalone power supply to perform data logging.
External power supply
The external power supply is used to power the OM-USB-5203 during data logging operations. This power
supply is a 2.5 W USB power adapter.
Disconnecting the OM-USB-5203 from the computer
You don't need to shut down your computer to disconnect the OM-USB-5203. Refer to the instructions below
when disconnecting the OM-USB-5203 from your computer's USB port.
When running Windows XP, use the Unplug or Eject icon on the computer's taskbar to safely stop the OMUSB-5203 before you unplug the device. To do this, right-click on the icon, select the OM-USB-5203 and click
Stop. Windows will notify you when it is safe to disconnect the device from your computer.
When running Windows 2000, the Unplug or Eject icon does not appear in the taskbar when the OM-USB-5203
is connected to the USB port. Do not disconnect the OM-USB-5203 from the computer when the device's LED
is flashing (transferring data), or data may be lost. When you disconnect the device, an Unsafe Removal of
Device warning may appear. However, no data is lost on the device when you remove the OM-USB-5203 when
the LED is steady green. This information applies to all OM-USB-5203 devices, regardless of the firmware
version installed.
Transferring binary data after a logging session
Data is stored on the memory card in binary files. After logging measurements, you can transfer the files to your
computer by reconnecting the OM-USB-5203 to a USB port on your computer or by removing the
CompactFlash card from the OM-USB-5203 and using a card reader connected to your computer.
Note that when installed with firmware version 3 and later the OM-USB-5203 appears as a Mass Storage
Device when connected to a USB port on your computer, so you can copy files using Windows Explorer.
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OM-USB-5203 User's Guide Functional Details
Converting binary data after a logging session
If your OM-USB-5203 is connected to a USB port on your computer, you can use InstaCal or TracerDAQ to
convert the files on the CompactFlash card to .CSV format for use in Microsoft Excel files, or to .TXT format
for use in other applications.
If you transferred binary files to your computer hard drive or removed the CompactFlash card from your OMUSB-5203 and are using a card reader connected to your computer, use TracerDAQ to import the files and save
them as .CSV or.TXT format. InstaCal can only convert files when the CompactFlash card is in a OM-USB5203 connected to your computer.
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Specifications
All specifications are subject to change without notice.
Typical for 25 °C unless otherwise specified.
Specifications in italic text are guaranteed by design.
Analog input section
Table 1. Generic analog input specifications
Parameter Conditions Specification
A/D converters Four dual 24-bit, Sigma-Delta type
Number of channels 8 differential
Input isolation 500 VDC minimum between field wiring and USB
interface
Channel configuration Software programmable to match sensor type
Differential input voltage
range for the various sensor
categories
Absolute maximum input
voltage
Input impedance 5 Gigohm, min.
Thermocouple ±0.080 V
RTD 0 to 0.5 V
Thermistor 0 to 2 V
Semiconductor sensor 0 to 2.5 V
±C0x through ±C7x relative to GND
(pins 9, 19, 28, 38)
Open thermocouple detect disabled 30 nA max.Input leakage current
±25 V power on, ±40 V power off.
Chapter 5
Open thermocouple detect enabled 105 nA max.
Normal mode rejection ratio fIN = 60 Hz
Common mode rejection
Ratio
Resolution 24 bits
No missing codes 24 bits
Input coupling DC
Warm-up time 30 minutes min.
Open thermocouple detect Automatically enabled when the channel pair is
fIN=50 Hz/60 Hz
15°C to 35°C ±0.25°C typ.,±0.5°C max.CJC sensor accuracy
0°C to 70°C -1.0 to +0.5°C max
90 dB min.
100 dB min.
configured for thermocouple sensor.
The maximum open detection time is 3 seconds.
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OM-USB-5203 User's Guide Specifications
Channel configurations
Table 2. Channel configuration specifications
Sensor Category Conditions Max number of
sensors (all channels
configured alike)
Disabled
Thermocouple J, K, S, R, B, E, T, or N 8 differential channels
Semiconductor sensor 8 differential channels
RTD and thermistor
Note 1: Internally, the device has four, dual-channel, fully differential A/Ds providing a total of eight
differential channels. The analog input channels are therefore configured in four channel pairs
with CH0/CH1 sensor inputs, CH2/CH3 sensor inputs, CH4/CH5 sensor inputs, and CH6/CH7
sensor inputs paired together. This "channel-pairing" requires the analog input channel pairs 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 channel 0 and a type T thermocouple on
channel 1) is valid.
Note 2: Channel configuration information is stored in the EEPROM of the isolated microcontroller by
the firmware 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 3: The factory default configuration is Disabled. The Disabled mode will disconnect the analog
inputs from the terminal blocks and internally ground all of the A/D inputs. This mode also
disables each of the current excitation sources.
2-wire input configuration with a single sensor per channel pair 4 differential channels
2-wire input configuration with two sensors per channel pair 8 differential channels
3-wire configuration with a single sensor per channel pair 4 differential channels
4-wire input configuration with a single sensor per channel pair 4 differential channels
4-wire input configuration with two sensors per channel pair 8 differential channels
Compatible sensors
Table 3. Compatible sensor type specifications
Parameter Conditions
Thermocouple
RTD
Thermistor Standard 2,252 ohm through 30,000 ohm
Semiconductor / IC TMP36 or equivalent
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 ohm PT (DIN 43760: 0.00385 ohms/ohm/°C)
100 ohm PT (SAMA: 0.003911 ohms/ohm/°C)
100 ohm PT (ITS-90/IEC751:0.0038505 ohms/ohm/°C)
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OM-USB-5203 User's Guide Specifications
Accuracy
Thermocouple measurement accuracy
Table 4. Thermocouple accuracy specifications, including CJC measurement error
Sensor Type Maximum error Typical error Temperature range
±1.499 °C ±0.507 °C -210 to 0°CJ
±0.643 °C ±0.312 °C 0 to 1200°C
±1.761 °C ±0.538 °C -210 to 0°CK
±0.691 °C ±0.345 °C 0 to 1372°C
±2.491 °C ±0.648 °C -50 to 250°CS
±1.841 °C ±0.399 °C 250 to 1768.1°C
±2.653 °C ±0.650 °C -50 to 250°CR
±1.070 °C ±0.358 °C 250 to 1768.1°C
±1.779 °C ±0.581 °C 250 to 700°CB
±0.912 °C ±0.369 °C 700 to 1820°C
±1.471 °C ±0.462 °C -200 to 0°CE
±0.639 °C ±0.245 °C 0 to 1000°C
±1.717 °C ±0.514 °C -200 to 0°CT
±0.713 °C ±0.256 °C 0 to 600°C
±1.969 °C ±0.502 °C -200 to 0°CN
±0.769 °C ±0.272 °C 0 to 1300°C
Note 4: Thermocouple measurement accuracy specifications include linearization, cold-junction
compensation and system noise. These specs are for one year, or 3000 operating hours,
whichever comes first, and for operation of the device between 15 °C and 35 °C. For
measurements outside this range, add ±0.5 degree to the maximum error shown. There are CJC
sensors on each 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. Please contact your thermocouple supplier for details on the actual thermocouple error.
Note 5: Thermocouples must be connected to the device such that they are floating with respect to GND
(pins 9, 19, 28, 38). The device GND pins are isolated from earth ground, so connecting
thermocouple sensors to voltages referenced to earth ground is permissible as long as the
isolation between the GND pins and earth ground is maintained.
Note 6: 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.
Semiconductor sensor measurement accuracy
Table 5. Semiconductor sensor accuracy specifications
Sensor Type Temperature Range (°C) Maximum Accuracy Error
TMP36 or equivalent -40 to 150°C ±0.50 °C
Note 7: Error shown does not include errors of the sensor itself. These specs are for one year while
operation of the device is between 15 °C and 35°C. Please contact your sensor supplier for
details on the actual sensor error limitations.
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OM-USB-5203 User's Guide Specifications
RTD measurement accuracy
Table 6. RTD measurement accuracy specifications
RTD Sensor
Temperature
PT100, DIN, US
or ITS-90
Note 8: Error shown does not include errors of the sensor itself. The sensor linearization is performed
-200°C to -150°C ±2.85 ±2.59
-150°C to -100°C ±1.24 ±0.97
-100°C to 0°C ±0.58 ±0.31
0°C to 100°C ±0.38 ±0.11
100°C to 300°C ±0.39 ±0.12
300°C to 600°C ±0.40 ±0.12
Maximum Accuracy Error (°C)
Ix+ = 210 µA
Typical Accuracy Error (°C)
Ix+ = 210 µA
using a Callendar-Van Dusen linearization algorithm. These specs are for one year while
operation of the device is between 15 °C and 35 °C. The specification does not include lead
resistance errors for 2-wire RTD connections. Please contact your sensor supplier for details on
the actual sensor error limitations.
Note 9: Resistance values greater than 660 ohms cannot be measured by the device in the RTD mode.
The 660 ohm resistance limit includes the total resistance across the current excitation (±Ix) pins,
which is the sum of the RTD resistance and the lead resistances.
Note 10: For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal value.
Thermistor measurement accuracy
Table 7. Thermistor measurement accuracy specifications
Thermistor Temperature Range Maximum Accuracy Error (°C)
I
= 10 µA
x+
2252 Ω -40 to 120°C ±0.05
3000 Ω -40 to 120°C ±0.05
5000 Ω -35 to 120°C ±0.05
10000 Ω -25 to 120°C ±0.05
30000 Ω -10 to 120°C ±0.05
Note 11: Error shown does not include errors of the sensor itself. The sensor linearization is performed
using a Steinhart-Hart linearization algorithm. These specs are for one year while operation of the
device is between 15°C and 35 °C. The specification does not include lead resistance errors for
2-wire thermistor connections. Please contact your sensor supplier for details on the actual sensor
error limitations. Total thermistor resistance on any given channel pair must not exceed
180 k ohms. Typical resistance values at various temperatures for supported thermistors are
shown in Table 8.
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OM-USB-5203 User's Guide Specifications
Table 8. Typical thermistor resistance specifications
Temp 2252 _
thermistor
-40°C 76 kΩ 101 kΩ 168 kΩ 240 kΩ (Note 12) 885 kΩ (Note 12)
-35°C 55 kΩ 73 kΩ 121 kΩ 179 kΩ 649 kΩ (Note 12)
-30°C 40 kΩ 53 kΩ 88 kΩ 135 kΩ 481 kΩ (Note 12)
-25°C 29 kΩ 39 kΩ 65 kΩ 103 kΩ 360 kΩ (Note 12)
-20°C 22 kΩ 29 kΩ 49 kΩ 79 kΩ 271 kΩ (Note 12)
-15°C 16 kΩ 22 kΩ 36 kΩ 61 kΩ 206 kΩ (Note 12)
-10°C 12 kΩ 17 kΩ 28 kΩ 48 kΩ 158 kΩ
-5°C 9.5 kΩ 13 kΩ 21 kΩ 37 kΩ 122 kΩ
0°C 7.4 kΩ 9.8 kΩ 16 kΩ 29 kΩ 95 kΩ
Note 12: Resistance values greater than 180k ohms cannot be measured by the device in the thermistor
3000 _ thermistor 5 k_ thermistor 10 k_ thermistor 30 k_ thermistor
mode. The 180 k ohm resistance limit includes the total resistance across the current excitation
(±Ix) pins, which is the sum of the thermistor resistance and the lead resistances.
Note 13: For accurate three wire compensation, the individual lead resistances connected to the ±Ix pins
must be of equal value.
Throughput rate to PC
Table 9. Throughput rate specifications
Number of Input Channels Maximum Throughput
1 2 Samples/second
2 2 S/s on each channel, 4 S/s total
3 2 S/s on each channel, 6 S/s total
4 2 S/s on each channel, 8 S/s total
5 2 S/s on each channel, 10 S/s total
6 2 S/s on each channel, 12 S/s total
7 2 S/s on each channel, 14 S/s total
8 2 S/s on each channel, 16 S/s total
Note 14: 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 temperature data is provided
by the USB unit is approximately 0.5 seconds. Throughput to CompactFlash memory card is
limited to 1 S/s per channel.
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Digital input/output
Table 10. Digital input/output specifications
Digital type CMOS
Number of I/O 8 (DIO0 through DIO7)
Configuration Independently configured for input or output.
Power on reset is input mode unless bit is configured for alarm.
Pull up/pull-down configuration All pins pulled up to +5 V via 47 K resistors (default). Pull down to ground
(GND) also available.
Digital I/O transfer rate
(software paced)
Input high voltage 2.0 V min., 5.5 V absolute max.
Input low voltage 0.8 V max., -0.5 V absolute min.
Output low voltage (IOL = 2.5 mA) 0.7 V max
Output high voltage (IOH = -2.5 mA) 3.8 V min.
Note 15: All ground pins on the device (pins 9, 19, 28, 38) are common and are 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 be referenced to earth ground.
Digital input – 50 port reads or single bit reads per second typ.
Digital output – 100 port writes or single bit writes per second typ.
Temperature alarms
Table 11. Temperature alarm specifications
Number of alarms 8 (one per digital I/O line)
Alarm functionality Each alarm controls its associated digital I/O line as an alarm output. The input to each
alarm may be any of the analog temperature input channels. When an alarm is enabled, its
associated I/O line is set to output (after the device is reset) and driven to the appropriate
state determined by the alarm options and input temperature. The alarm configurations are
stored in non-volatile memory and are loaded at power on. Alarms will function both in
data logging mode and while attached to USB.
Alarm input modes
Alarm output modes
Alarm update rate 1 second
Alarm when input temperature > T1
Alarm when input temperature > T1, reset alarm when input temperature goes below T2
Alarm when input temperature < T1
Alarm when input temperature < T1, reset alarm when input temperature goes above T2
Alarm when input temperature is < T1 or > T2
Note: T1 and T2 may be independently set for each alarm.
Disabled, digital I/O line may be used for normal operation
Enabled, active high output (digital I/O line goes high when alarm conditions met)
Enabled, active low output (digital I/O line goes low when alarm conditions met)
Memory
Table 12. Memory specifications
EEPROM 1,024 bytes isolated micro reserved for sensor configuration
256 bytes USB micro for external application use
256 bytes USB micro reserved for data logging configuration
Microcontroller
Table 13. Microcontroller specifications
Type Two high performance 8-bit RISC microcontrollers
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OM-USB-5203 User's Guide Specifications
Data Logging
Table 14. Data logging specifications
Standalone power
supply
Memory card type CompactFlash
Supplied memory
card
Memory card host
access
File systems
supported
Log file format binary
Logging rate Min 1 second between entries, max 232 seconds, 1 second granularity
Data items logged Timestamp, temperature or raw reading from selected channels, state of DIO lines, CJC sensor
Logging start
methods
Logging stop
methods
Logging status
indication
USB power adapter (part number OM-USB-Adapter):
2.5 Watt USB adapter with interchangeable plugs (includes plug for USA)
512 MB CFCard: 512 MB Compact Flash Card for Omega Engineering dataloggers
USB Mass Storage Device (MSD)
FAT16, FAT32
The device only creates 8.3 file names in the root subdirectory.
readings
Configurable:
Start Logging on Power Up – Logging begins 5 seconds after power on to allow hardware to
settle.
Start Logging on Button – Device is idle on power on, press and hold button until LED comes
on to begin logging. The first sample will be taken 1 second after LED comes on unless less
than 5 seconds have elapsed since power on.
Start Logging at Specified Time – Device is idle until the real time clock indicates the time is
equal to or greater than the specified time, at which time the LED will come on. The first
sample will be taken 1 second after LED comes on unless less than 5 seconds have elapsed
since power on.
Note: Data logging is not allowed when the device is attached to an active USB bus due to
processing limitations. The device must be connected to the standalone power supply to perform
data logging.
Stop on button press – To stop logging, press and hold button until LED turns off.
Note: The device caches log data in volatile memory prior to writing to memory card. When
logging, always use the button to stop logging and ensure data is written to memory card prior to
removing power.
The LED operations when connected to the AC adapter power supply are different than when
connected to USB:
Logging modes:
Logging Off mode: the LED is off (disabled).
Start Logging on Power Up mode: the LED is on, with a momentary off flash every time data
is captured.
Start Logging on Button mode: the LED is initially off. When the button is pressed and held
for approximately 1 second the LED will turn on and act the same as Start Logging on Power
Up mode.
Start Logging at Specified Time mode: the LED is off, with a momentary on flash every
second until the specified date/time is reached. At that time, the LED will turn on and act the
same as Start Logging on Power Up mode.
Other indication:
To stop logging and store the remaining data to memory card, press and hold the button until
the LED turns off. It is then safe to remove the memory card.
If the memory card becomes full the LED will blink rapidly (250 ms period).
If the memory card is removed while logging is in progress the LED will blink rapidly (250 ms
period). Inserting a memory card will stop the blinking.
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OM-USB-5203 User's Guide Specifications
Real time clock
Table 15. Real time clock specifications
Battery backup CR-2032 lithium coin cell, replaceable
Accuracy ±1 minute per month
USB +5V voltage
Table 16. USB +5V voltage specifications
Parameter Conditions Specification
USB +5V (VBUS) input voltage range 4.75 V min. to 5.25 V max.
Power
Table 17. Power specifications
Parameter Conditions Specification
Connected to USB
Supply current USB enumeration <100 mA
Supply current (Note 16) Continuous mode 500 mA max.
User +5V output voltage range
(terminal block pin 21 and 47)
User +5V output current
(terminal block pin 21 and pin 47)
Isolation Measurement system to PC 500 VDC min.
AC Adapter Power Supply (used for data logging operation)
Output voltage 5V ±5%
Output wattage 2.5W
Input voltage 100 – 240 VAC
Input current 0.2A
Note 16: This is the total current requirement for the device which includes up to 10 mA for the status
LED.
Note 17: Self-Powered Hub refers to a USB hub with an external power supply. Self-powered hubs allow
a connected USB device to draw up to 500 mA. This device may not be used with bus-powered
hubs due to the power supply requirements.
Connected to a self-powered hub. (Note 17) 4.75 V min. to
5.25 V max.
Connected to a self-powered hub. (Note 17) 10 mA max.
50 – 60 Hz
Root Port Hubs reside in the PC’s USB Host Controller. The USB port(s) on your PC are root
port hubs. All externally powered root port hubs (desktop PC's) provide up to 500 mA of current
for a USB device. Battery-powered root port hubs provide 100 mA or 500 mA, depending upon
the manufacturer. A laptop PC that is not connected to an external power adapter is an example
of a battery-powered root port hub.
32
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OM-USB-5203 User's Guide Specifications
USB specifications
Table 18. USB specifications
USB device type USB 2.0 (full-speed)
Device compatibility USB 1.1, USB 2.0
Self-powered, 500 mA consumption max.
USB cable type A-B cable, UL type AWM 2527 or equivalent. (min 24 AWG VBUS/GND, min
28 AWG D+/D-)
USB cable length 3 meters max.
Current excitation outputs (Ix+)
Table 19. Current excitation output specifications
Parameter Conditions Specification
Configuration 4 dedicated pairs:
±I1 - CH0/CH1
±I2 - CH2/CH3
±I3 - CH4/CH5
±I4 - CH6/CH7
Thermistor 10 µA typ.Current excitation output ranges
RTD 210 µA typ.
Tolerance ±5% typ.
Drift 200 ppm/°C
Line regulation 2.1 ppm/V max.
Load regulation 0.3 ppm/V typ.
Output compliance voltage (relative
to GND pins 9, 19, 28, 38)
Note 18: The device has four current excitation outputs, with ±I1 dedicated to the CH0/CH1 analog inputs,
±I2 dedicated to CH2/CH3, ±I3 dedicated to CH4/CH5, and ±I4 dedicated to CH6/CH7. The
excitation output currents should always be used in this dedicated configuration.
Note 19: The current excitation outputs are automatically configured based on the sensor (thermistor or
RTD) selected.
3.90 V max.
-0.03 V min.
Environmental
Table 20. Environmental specifications
Operating temperature range 0 to 70°C
Storage temperature range -40 to 85°C
Humidity 0 to 90% non-condensing
Mechanical
Table 21. Mechanical specifications
Dimensions 127 mm (L) x 88.9 mm (W) x 35.56 (H)
User connection length 3 meters max.
33
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OMB-USB-5203 User's Guide Specifications
Screw terminal connector type and pin out
Table 22. Screw terminal connector specifications
Connector type Screw terminal
Wire gauge range 16 AWG to 30 AWG
Screw terminal pin out
Table 23. Screw terminal pin out
Pin Signal Name Pin Description Pin Signal Name Pin Description
1 I1+ CH0/CH1 current excitation source 27 I4- CH6/CH7 current excitation return
2 NC 28 GND
3 C0H CH0 sensor input (+) 29 C7L CH7 sensor input (-)
4 C0L CH0 sensor input (-) 30 C7H CH7 sensor input (+)
5 4W01 CH0/CH1 4-wire, 2 sensor common 31 IC67 CH6/CH7 2 sensor common
6 IC01 CH0/CH1 2-sensor common 32 4W67 CH6/CH7 4-wire, 2 sensor common
7 C1H CH1 sensor input (+) 33 C6L CH6 sensor input (-)
8 C1L CH1 sensor input (-) 34 C6H CH6 sensor input (+)
9 GND 35 NC
10 I1- CH0/CH1 current excitation return 36 I4+ CH6/CH7 current excitation source
CJC sensor CJC sensor
11 I2+ CH2/CH3 current excitation source 37 I3- CH4/CH5 current excitation return
12 NC 38 GND
13 C2H CH2 sensor input (+) 39 C5L CH5 sensor input (-)
14 C2L CH2 sensor input (-) 40 C5H CH5 sensor input (+)
15 4W23 CH2/CH3 4-wire, 2 sensor common 41 IC45 CH4/CH5 2 sensor common
16 IC23 CH2/CH3 2 sensor common 42 4W45 CH4/CH5 4-wire, 2 sensor common
17 C3H CH3 sensor input (+) 43 C4L CH4 sensor input (-)
18 C3L CH3 sensor input (-) 44 C4H CH4 sensor input (+)
19 GND 45 NC
20 I2- CH2/CH3 current excitation return 46 I3+ CH4/CH5 current excitation source
21 +5V +5V output 47 +5V +5V output
22 GND 48 GND
23 DIO0 Digital Input/Output 49 DIO7 Digital Input/Output
24 DIO1 Digital Input/Output 50 DIO6 Digital Input/Output
25 DIO2 Digital Input/Output 51 DIO5 Digital Input/Output
26 DIO3 Digital Input/Output 52 DIO4 Digital Input/Output
34
Page 35
WARRANTY/DISCLAIMER
OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a
period of 13 months from date of purchase. OMEGA’s WARRANTY adds an additional one (1) month
grace period to the normal one (1) year product warranty to cover handling and shipping time. This
ensures that OMEGA’s customers receive maximum coverage on each product.
If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service
Department will issue an Authorized Return (AR) number immediately upon phone or written request.
Upon examination by OMEGA, if the unit is found to be defective, it will be repaired or replaced at no
charge. OMEGA’s WARRANTY does not apply to defects resulting from any action of the purchaser,
including but not limited to mishandling, improper interfacing, operation outside of design limits,
improper repair, or unauthorized modification. This WARRANTY is VOID if the unit shows evidence of
having been tampered with or shows evidence of having been damaged as a result of excessive corrosion;
or current, heat, moisture or vibration; improper specification; misapplication; misuse or other operating
conditions outside of OMEGA’s control. Components in which wear is not warranted, include but are not
limited to contact points, fuses, and triacs.
OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any
damages that result from the use of its products in accordance with information provided by
OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by the
company will be as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR
REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESSED OR IMPLIED, EXCEPT THAT OF
TITLE, AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF
LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of
OMEGA with respect to this order, whether based on contract, warranty, negligence,
indemnification, strict liability or otherwise, shall not exceed the purchase price of the
component upon which liability is based. In no event shall OMEGA be liable for
consequential, incidental or special damages.
CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or
activity, medical application, used on humans, or misused in any way, OMEGA assumes no responsibility
as set forth in our basic WARRANTY/ DISCLAIMER language, and, additionally, purchaser will indemnify
OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the
Product(s) in such a manner.
RETURN REQUESTS/INQUIRIES
Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE
RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN
(AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID
PROCESSING DELAYS). The assigned AR number should then be marked on the outside of the return
package and on any correspondence.
The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent
breakage in transit.
FOR WARRANTY
RETURNS, please have the
following information available BEFORE
contacting OMEGA:
1. Purchase Order number under which the product
was PURCHASED,
2. Model and serial number of the product under
warranty, and
3. Repair instructions and/or specific problems
relative to the product.
FOR NON-WARRANTY REPAIRS,
consult OMEGA
for current repair charges. Have the following
information available BEFORE contacting OMEGA:
1. Purchase Order number to cover the COST
of the repair,
2. Model and serial number of the product, and
3. Repair instructions and/or specific problems
relative to the product.
OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords
our customers the latest in technology and engineering.
OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2010 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,
reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the
prior written consent of OMEGA ENGINEERING, INC.
Page 36
M4896/0410
Where Do I Find Everything I Need for
Process Measurement and Control?
OMEGA…Of Course!
Shop online at omega.com
SM
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