1 Channel 220V AC optocoupler module can be used to detect the presence or absence of 220V AC power; The output TTL level can be detected by a microcontroller, stabilizing the output of high and low levels (NPN output); When detecting 220V input, the LED light is on, and the optocoupler is conducting and outputting a low level; When there is no 220V input, the LED light does not light up, the optocoupler is not connected, and the output is pulled high by a resistor; The output power supply can be
DC: 3V~24V, or it can be connected to a PLC 24V level