Owner's manual

6
Chapter 1
Introducing the OM-USB-TEMP
Overview: OM-USB-TEMP features
This user's guide contains all of the information you need to connect the OM-USB-TEMP
to your computer and
to the signals you want to measure.
The OM-USB-TEMP is a USB 2.0 full-speed, temperature measurement module that is supported under popular
Microsoft
®
Windows
®
operating systems. The OM-USB-TEMP is fully compatible with both USB 1.1 and USB
2.0 ports.
The OM-USB-TEMP 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-TEMP, 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 Ω platinum RTDs
Thermistors – 2, 3, or 4-wire measurements
Semiconductor temperature sensors – LM36 or equivalent
The OM-USB-TEMP 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-TEMP 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-TEMP 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 OM-USB-TEMP is fully software calibrated.