How to Convert 2 wire RTD into 3 or 4 wire RTD?

Learn how to convert a 2 wire RTD into 3 or 4 wire RTD sensors. This procedure helps us to reduce the temperature measurement error of 2 wire RTD.

Do you have a 2 wire RTD?

The lead wire resistance of 2 wire RTD impacts the temperature measurement and gives a considerable amount of error reading. If the distance between the 2 wire RTD sensor and transmitter is more then your error will be more.

For example, If the real process temperature is 150 deg c then the moderate distance between sensor and transmitter gives a large measurement error. Say we may get 154 deg c.

These types of errors are not acceptable. Its always recommended using a 3 wire RTD or a 4 wire RTD sensor in industrial measurement applications.

Are you getting a large temperature reading error due to two-wire RTD?

Are you stuck with 2 wire RTD but looking to reduce the measured temperature error?

Then you have to connect your 2 wire RTD to the temperature transmitter in either a 3 wire RTD connection or 4 wire RTD connection.

Is this really work? Yes, it is. Your error will be drastically reduced.

Is this configuration will be as same as using a 3 wire RTD or 4 wire RTD? NO, it just helps you to improve the temperature measurement with 2 wire RTD.

Convert 2 wire RTD to 3 wire RTD

Learn how to convert your 2 wire RTD into a 3 wire RTD.

You have to connect an extra cable between any one of the terminals of RTD and 3rd terminal of the temperature transmitter.

The temperature transmitter must be configured as a 3 wire RTD sensor.

This configuration helps you to reduce the temperature measurement error of 2 wire RTD. You can follow this procedure when you don’t have the option to use a 3 wire RTD sensor.

Note: This is procedure is not a replacement for using a 3 wire RTD sensor.

The measurement error will be reduced when compared to the 2 wire RTD. The measurement error will be more when compared to the 3 wire RTD.

Convert 2 wire RTD to 4 wire RTD

Learn how to convert your 2 wire RTD into a 4 wire RTD.

You need two extra cables to connect the 2 wires to the temperature transmitter.

The temperature transmitter must be configured with a 4 wire RTD sensor even though we are using the 2 wire RTD.

Please note, this configuration only helps you to reduce the temperature measurement error and it is not a recommended method to replace a 4 wire RTD sensor. It just reduces the measurement error of 2 wire RTD.

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