LEVEL OUTPUT: When the 220V voltage is normal, photoelectric isolated module outputs a low level. When the 220V is powered off, it outputs a high level, output can be connected to PLC 24vb APPLICATION: Voltage detection board is used to detect whether AC 220V exists, can also use MCU for testing, and the working voltage is 3‑5V PLC CONNECTION: When connecting the PLC input, the COM terminal is connected to the 24V power supply, the input terminal is connected to the output S1‑S8 of the board, and the optocoupler GND is connected to the negative pole of the power supply MATERIAL: 8 channel optocoupler board adopts PCB material, not easy to malfunction, very for long term use, small in size, light in weight EASY INSTALLATION: The optocoupler photoelectric isolator module blue 5.0 terminal is connected to the 220V voltage, and the yellow pin is the output, convenient to use and install Specification:
Item Type: Optocoupler Isolation Board
Material: PCB
Function: Test whether AC 220V exists. 
Output TTL Level: MCU can be used for testing, the voltage is 3-5V. 
Connection: Output can be connected to PLC 24Vb. 

Package List:
1 x Optocoupler Isolation Board

Note:
After the module is powered up, do not touch any part of the white wire frame on the board high voltage. Pay attention to electrical safety.