feature: Function: test whether AC 220V exists Output TTL level: can be tested with MCU, voltage 3-5V Output can be connected to PLC 24V wiring: When connecting to the PLC input, the COM terminal of the PLC is connected to the 24V power supply, the input connection board signal output S1-S8, 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 220V voltage is normal, it outputs low level; when 220V power is off, it outputs high level. notes: Do not touch any part of the white wire frame on the board after the module is powered on, because it is a high voltage. Pay attention to electricity safety. size: 138 x 56MM Material:PCB colour:Green Package Contents: 1 x 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.