Resistance and RTD Input Mode

Resistance and RTD Readings

The FAC-2100 uses a three-wire technique to read resistors and RTD sensors. This technique involves having one wire (signal) connected to one end of the resistor and two wires (common) be connected to the other end. The advantage of this technique is that the resistance associated with the cable negated and only the resistance of the sensor element is measured.

Wiring Diagram

The following figure shows the typical wiring for a resistor or RTD:

Example Analog Input Wiring for Reading a Resistor or RTD

If the reading error associated with the resistance of the cable is not significant for your system (or can be compensated for using some other means) then it is possible to use a two wire cable and short the ground and A_IN- pins together in the FAC-2100 connector.