Welcome to the store! TTL output level can be detected by the microcontroller. Power supply can be 3-5V. Can also connect to PLC 24V level. Then PLC input terminal of PLC COM power supply 24V input termination of the board's signal output OUT, optocoupler board GND power supply negative. Blue 2P 5.0 terminal connected to 220V voltage. 3P terminal connected to the microcontroller input. Specification: 1. Board size: 73x15mm 2. Function: Tests if AC 220V is present. Color: Green Material: Plastic Package Contents: 5 x Optocoupler Isolation Module Warning: When the power module on the board is powered, the white wire frame cannot contact any device, as it is high voltage. Please be careful with electricity. (Note: Only the above package content is included; other products are not. Light and different displays may cause the color of the item in the picture to be slightly different from the real thing. The allowed measurement error is +/- 1-3cm.) Your satisfaction is our top priority. We will provide you with the best service. If you find any issues after receiving the product, such as damage, incorrect quantity, etc., please contact us immediately, and we will provide you with the best solution!