OM-USB-5203 User's Guide
Sensor Connections
14
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. The software outputs the
measurement data as 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 the
sensor.
Wiring configuration
Connect the semiconductor sensor to the OM-USB-5203 using a single-ended configuration, as shown in Figure
10. The OM-USB-5203device provides
+5V
and
GND
pins for powering the sensor.
Figure 10. Semiconductor sensor measurement configuration
