Pneumatic Threshold Valves are ideally suited to turn on or off a light, or to send an electric signal to another function in the system. They are supplied with core cable and can be used with AC or DC voltages.

A pneumatic sensor fitting detects the absence of pressure and translates it to a high pressure pneumatic output. The exhaust pressure is sensed by a N/O, N/C contract relay switch. When used to monitor the decaying or exhausting side of a pneumatic cylinder's piston, this threshold sensor emits a positive output. When the cylinder comes to the end of its stroke, wherever that may be, the signal emitted from the sensor can then be used to pilot the next step pressure.

Hence, a threshold sensor fitting detects pressure drop and the cylinder end-of-travel and thus provides an outlet pilot signal. These sensors eliminate on going normal adjustment associated with limit valves and replaces traditional sequence valves and/or limit switches.

The threshold sensor can be mounted on the cylinder, on the control valve or on a terminal block (provided it is between the cylinder and the flow control). For accuracy, the flow control should be mounted as close as possible to the cylinder. It can be fitted to a sensor fitting mounted on the cylinder.