How to Select an RTD?


When selecting the right Platinum Resistance Thermometers (also known as RTDs, Pt100 rtd & rtd probe), there are many things that need to be considered.

By asking a few questions we can normally work out what RTD sensor you want. However, in many cases our customers are left to source items with minimal information provided to them from a third party customer or engineer within the organisation.

Alternatively, you may simply have a new application which needs temperature measurement and have never purchased this type of product. Again, we are able to help.

Below we discuss the 7 steps you need to consider in order to get the right RTD sensor for your application.

1. Element Type

Do you know the RTD element type you need? Such as Pt100 or Pt1000. If not, this is the first thing you need to consider. Whatever you are connecting the RTD sensor to normally determines this.

2. Application

What is being measured? Is the rtd probe measuring a liquid, surface or a gas? Does it have to sit in a pipe or a vessel or is it part of a machine or apparatus?

3. Environment

What considerations need to be thought about? E.g. Does it need to be chemically resistant, IP rated, ATEX approved, food use, high vibration?

4. Location

How is the RTD fixed to the application, such as; wall mounted, hand held, outside or inside. Does it need a fitting to be held in place?

5. Operating Range

(E.g. 0 – 1000 Deg C) This is the main limiting factor when choosing RTD sensors as it determines the materials used in the construction.

6. Physical Considerations

What are the length, diameter and size requirements? Does is need to be bent or extremely long?

7. Connection to Application

What is the RTD being connected to? Does it need a terminal head, connector, wire or transmitter? You also need to understand if you need 2 wire, 3 wire or 4 wire configuration.

Reference : sterlingsensors