Electronic sensors

Electronic sensors include inductive, optical and capacitive proximity sensors. They generally have three electrical connections for:

• supply voltage,

• earth,

• output signal. In the case of electronic sensors, no movable contact is switched over. Instead the output is either electrically connected with the supply voltage or to earth (= output voltage 0 V).

When it comes to the polarity of the output signal, there are two different designs of electronic proximity sensor:

• In the case of positive-switching electronic sensors, the output has a voltage of zero (OFF) when there is no part within the sensor's response range. The approach of a workpiece results in the output being switched over (ON) so that supply voltage is applied.

• In the case of negative-switching sensors, supply voltage is applied to the output when there is no part within the sensor's response range. The approach of a workpiece results in the output being switched over to a voltage of 0 V.