RTD Advantages and Disadvantages
Advantages:
The response time compared to thermocouples is very fast – in the order of fractions of a second.
An RTD will not experience drift problems because it is not selfpowered.
Within its range it is more accurate and has higher sensitivity than a thermocouple.
In an installation where long leads are required, the RTD does not require special extension cable.
Unlike thermocouples, radioactive radiation (beta, gamma and neutrons) has minimal effect on RTDs since the parameter measured is resistance, not voltage.
Disadvantages:
Because the metal used for a RTD must be in its purest form, they are much more expensive than thermocouples.
In general, an RTD is not capable of measuring as wide a temperature range as a thermocouple.
A power supply failure can cause erroneous readings
Small changes in resistance are being measured, thus all connections must be tight and free of corrosion, which will create errors.
Failure Modes:
An open circuit in the RTD or in the wiring between the RTD and the bridge will cause a high temperature reading.
Loss of power or a short within the RTD will cause a low temperature reading.