See the related feature article:
Getting the Best Sensor Data
Careful selection of temperature measurement devices can improve the efficiency of your system.
In almost every industrial environment, radio frequency interference (RFI) and electromagnetic interference (EMI) can have negative effects on process signals.
The low level signals generated from RTDs and thermocouples are susceptible to the signal-degrading effects of RFI and EMI when using direct wiring. Further, the sensor extension wires even can act as an antenna and draw noise to the wires.
Temperature transmitters will negate the effects of RFI noise by converting the low level signal received from the sensor to a high level analog signal. This high-level signal is resistant to RFI/EMI and can travel through a noisy plant to the control room.