Both thermocouples and RTDs are useful sensors for determining process temperature.
Thermocouples are generally less expensive than RTDs. They are more durable in high vibration or mechanical shock applications and are usable to higher temperatures. Thermocouples can be made smaller in size than most RTDs and they can be formed to fit a particular application.
It is best to use thermocouples when:
• Point, rather than area sensing, improves control.
• The element will be used in applications with temperatures in excess of 650°C
• The element will be used in high vibration or mechanical shock applications.
• Cost is an issue.
RTDs provide higher accuracy than thermocouples in their temperature range because platinum is a more stable material than most thermocouple materials. RTDs also use standard instrumentation wire to connect to the measurement or control equipment, which has the ability to decrease the overall installation cost.
It is best to use RTDs when:
• Accuracy and stability are requirements of the customer’s specification.
• Accuracy must extend over a wide temperature range.
• Area, rather than point sensing, improves control.
• A high degree of standardisation is desirable.
When choosing a sensor, it is advisable to always seek technical advice to ensure that you select the best sensor, most suitable sensor for your unique needs. Contact our experienced sales team at Pyrosales for assistance in finding the right temperature sensor for your application.
Both thermocouples and RTDs are available from Pyrosales .