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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 Ω platinum RTDs.
Thermistors – 2, 3, or 4-wire measurement modes.
Semiconductor temperature sensors – LM35 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 pinout
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
Use 16 AWG to 30 AWG wire for your signal connections.
Tighten screw terminal connections
Fully tighten the screw when making connections to the screw terminals. 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.
