How To Connect This Proximity Sensor?

1) There are two-wire and three-wire proximity sensors. Three-wire proximity switches are divided into NPN type and PNP type, and their wiring is different. Please see the following diagram.  

  (2) The wiring of the two-wire proximity sensor is relatively simple; the proximity sensor can be connected in series with the load and then connected to the power supply. 

  (3) Three-wire proximity sensor wiring: the red (brown) wire is connected to the positive side of the power supply; the blue wire is connected to the 0V side of the power supply; the yellow (black) wire is the signal, which should be connected to the load. The other end of the load is connected in this way: for NPN type proximity switch, it should be connected to the positive side of the power supply; for PNP type proximity switch, it should be connected to the 0V side of the power supply. 

  4) The load of the proximity sensor can be a signal lamp, a relay coil or a digital input module of the PLC of the programmable logic controller. PLC digital input modules can be divided into two categories: one common input for the power supply 0V, current flow out of the input module (Japanese mode), at this time, must use the NPN type proximity switch; the other common input for the positive power supply, current flow into the input module, that is, the trap input (Europe). (mode), in this case, always use a PNP type proximity sensor. Do not choose the wrong one. 

  6) The two-wire proximity sensor is limited by the working conditions, a certain voltage drop is generated by the switch itself when it is on, and a certain residual current flows when it is off, which should be considered when choosing the switch. Three-wire proximity switch, though having one more wire, is not troubled by the unfavorable factors such as residual current and works more reliably.