Pressure transmitter 4–20 mA in natural gas: how pressure is converted into a signal

In installations with PLC or BMS, natural gas pressure is often measured with a pressure transmitter that sends an analog 4–20 mA signal.

What does 4–20 mA mean?

4 mA typically corresponds to the lower limit of the scale and 20 mA to the upper limit.

Example

If the transmitter is 0–1 bar, the PLC converts the electrical signal into the corresponding pressure value.

Scaling in the PLC

If the scale is configured incorrectly, the display may show incorrect pressure even though the sensor is functioning correctly.

Advantages

Continuous measurement allows for trends, alarms, and correlation of pressure with load and flow rate.