Normally open (NO) and normally closed (NC), the difference between:
Normally open (NO) is a common condition signal output wire for the disconnected state, no output signal is only closed when the sensed object, the output signal.
Normally closed (NC) is a common condition signal output line closed, continuous signal output, only disconnected when the sensing object, turn off signal.
Two types of proximity switches according to the actual needs.

Three-wire connection method:
Color cast is the positive pole of the power supply, blue is the negative pole of the power supply, black is the load (output signal). For details, please read the wiring diagram on the baby.

Two connection methods of line (DC or AC):
Brown line cathode connected load, load the positive line and then connect the power of the cathode, anode of direct connection blue power supply.

Specific methods please refer to the wiring diagram on the switch plate to wiring, do not reverse wrong!