Pressure switch calibration procedure

The pressure switch is used in The industry to alert the operator by the means of alarm. It is used as an interlock to start/stop any equipment. It is one of the important instrument play a major role in safe operation, hence the proper calibration is essential. And let us discuss the procedure of Low and high switch.

Low pressure switch calibration procedure

1.Follow the safety and standard procedure before calibration

2.Make ready of equipment And tools before starting the calibration

3.Connect the pressure calibrator, deadweight tester or handpump with proper fitting. Check for leakage arrest it before start calibrating.

For example, we want to calibrate the Low switch for 2kg/cm2. 

4.Apply the pressure above 2. If the hysteresis of the switch is 0.2 then rise to 2.2 kg and adjust the set point in the pressure switch. Low switch setpoint has to be set while falling pressure.

5.Now drop the pressure and rise above 2.2 kg and gradually release the pressure And check whether the contact is getting changed on 2kg. If an error occurs rise the pressure and again repeat the above step until the setpoint is set to 2 kg/cm2 while falling.

High pressure switch calibration procedure

The calibration procedure is the same as low pressure but instead of setting the limit while falling pressure, the pressure limit has to be set while raising pressure itself. In the process, the normal pressure is maintained in case the pressure reaches a high pressure the switch will be get activated. So to keep the circuit during normal process condition the contact of the switch is taken as NORMALLY CLOSED. And the circuit will open in case the high switch acted.

For example, we want to calibrate the High switch for 5kg/cm2. 

Gradually apply the pressure using any calibrator until 5kg/cm2. And set the limit by adjusting the port given in the switch. And again drop the pressure, check the reset point. Again rise the pressure and check whether the contact getting change over at 5kg/cm2. If any deviation occurs repeat the procedure until the switch set to the required setpoint.