Function: test whether AC 220V exists Output TTL level: MCU can be used for testing, the voltage is 3-5V Output can be connected to PLC 24V wiring: When connecting the PLC input, the terminal of the PLC is connected to the 24V power supply, the input end is connected to the signal output S1-S8 of the board, and the optocoupler GND is connected to the negative pole of the power supply. The blue 5.0 terminal is connected to 220V voltage, and the yellow pin is signal output. When the 220V voltage is normal, the output is low level; when the 220V power is off, the output is high level. size:73mm X15mm Material:PCB colour:green Package Contents: 1 * optocoupler module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.