This is an 8 channel one-way transmission digital signal converter
When connecting the PLC input, the PLC's COM terminal is connected to the 24V power supply, the input is connected to signal outputs S1-S8 of the board, optocoupler GND is connected to the power supply negative.
When the 220V voltage is normal, it output low level; when 220V is powered off, it output a high level.
Blue 5.0 terminal is connected to 220V voltage, yellow pin signal output. 3.When the 220V voltage is normal, it output low level; when 220V is powered off, it output a high level.