The model PSM-630 is used in industrial control, monitoring and alarm applications. The switch point can be adjusted by the customer on site. The instrument can switch electrical loads of up to AC 440 V, 16 A. The integrated relief valve (option) is used for depressurising the pressure chamber of the compression piston before starting the compressor. With the manual On/Off knob, the contact system can be locked in the open position, irrespective of the process pressure.