Measuring Temperature with an RTD

An RTD is a temperature sensing device with resistance that increases with temperature.

Signal conditioning is generally required to measure temperature using an RTD. Because an RTD is a passive resistive device, you must pass a current through the device to produce a measurable voltage. Providing current to take a resistive measurement is a form of signal conditioning called current excitation. In addition to producing current excitation for the RTD, signal conditioning amplifies the output voltage signal, and filters the signal to remove unwanted noise. You also can use signal conditioning to electrically isolate the RTD and the monitored system from the DAQ system and the host computer.