Frequently asked questions

PNP and NPN type outputs are available as 3-wire sensors with a DC voltage power supply (the voltage limits are dependent on the specific sensor):

 

PNP type: switching on the positive voltage load

NPN type: switching on the negative voltage load

These outputs are typical of photoelectric detectors, inductive proximity and other types of sensors.

 

PNP output

The load (relay coil, contactor relay input, PLC input) must be connected between the "-" negative terminal and the midpoint.

The corresponding PLC input is Sink.

 

NPN output

The load must be connected between the "+" positive terminal and the midpoint.

The corresponding PLC input is Source.


 

Some sensors have two PNP and NPN outputs (4-wire sensors) which are wired according to the diagram below.



Note that wiring diagrams can be found on the instructions provided with / for a sensor, or in the catalogue. All this documentation is found online at www.se.com or www.tesensors.com