The input components commonly used in industrial control are mainly switches, such as knob switch, push button switch, travel switch, proximity switch, encoder, etc., as shown below: Commonly used PLC input switch These switches are available in two-wire (button, knob, travel switch), three-wire (proximity switch), four-wire (encoder), and the input types of these switches are NPN, PNP. The output signal of the NPN type sensor switch is connected to the low level (Power Supply 0V) through the switch tube. When the sensor receives the signal action, the switch tube is turned on and outputs a low level signal; the PNP type output signal is connected with the high level ( The power supply 24v) is connected. When the sensor receives the signal action, the switch tube is turned on and outputs a high level signal. Line PLC input type: PLC external wiring has leakage type, source type input, PLC leakage type input, as shown below: Sink input The so-called leakage and source type input is for the common S/S of the PLC. When the 24V DC power supply flows from the common S/S terminal and flows out from the input terminal (X), it becomes a sink type input, when 24v DC When the power supply flows from the input terminal (x) to the common terminal, it is the source input. It can be seen that when the leakage type input, the common terminal S/S is connected to the DC power supply +24v, and the source input is connected to the S/S DC power supply 0v. . Source input How to choose the input type of the switch? In the use of a PLC basic unit, only one type of connection type or source type can be used. For a two-wire type of switch, both methods can be used, as shown below: Sink input Source input For the wiring of the three-wire sensor, it is necessary to pay attention to the connection. According to the above description of the NPN to the PNP sensor, the NPN open-collector sensor corresponds to the PLC sink input. NPN type sensor For the PNP open collector type sensor, the PLC source type input needs to be selected. For example, the proximity switches and sensors listed in the above figure are all NPN type, and the connection is as follows: NPN type proximity switch and PLC connection NPN type encoder and PLC connection The above is the common connection diagram between the industrial control input device and the PLC. According to the switch type, select the corresponding PLC input type to connect successfully. When wiring, be sure to check the switch type. Available Usb Receiver Mouse,Wireless Mouse Bluetooth,Office Pc Bluetooth,Pc General Purpose Bluetooth Guangzhou Lufeng Electronic Technology Co. , Ltd. , https://www.lufengelectronics.com
