A pressure transmitter is one of the most common instruments in a process plant. In order to assure its accuracy, it needs to be calibrated. But what do you need to calibrate it and how is it done?
The pressure transmitter’s purpose is to convert the pressure signal into an electric signal that is easy to transport into the control system, which may be located far from the pressure measurement location. Most commonly the pressure is converted into a 4 … 20 mA standardized signal.
Anyhow, the transmitter’s accuracy is about how accurately it converts the input pressure into the mA signal. If you want to know that, then you need to calibrate the transmitter.
In order to calibrate a pressure transmitter, you need:
- loop supply (if not connected to controls system’s loop supply)
- a pressure generator to generate input pressure
- an accurate calibrator to measure the input pressure
- an accurate calibrator to measure the output mA current.
Typically, the pressure transmitter is a HART protocol transmitter, so in case there is any need to adjust/trim it, you will need to use a device supporting HART communication.
So, how to calibrate? Explaining how to do the calibration would result in quite a long text, so we have put together a video for you instead. The video shows you how to calibrate and trim a HART pressure transmitter.
Please have a look at the video:
- Video: How to calibrate a profibus pressure transmitter
- Blog post: Why must also "Smart" transmitters be calibrated?
- Blog post: Calibration of a HART transmitter and the most common misconceptions about a HART communicator
- Blog post: Why calibrate?