Item Type: 4-Channel Relay Module_x000D_Relay Communication: Multi-unit network 485 communication, the default communication address is 1, and the user can modify the address by himself_x000D_Note: IN1-IN4 are used to connect to the switch and read the switch status through 485, not to control the relay output through the input._x000D_The switch status of IN1-IN4 needs to be read by the computer every time it is inquired, and data cannot be sent to 485 actively._x000D_Note: IN1-IN4 cannot be connected to 220V (some buyers will make this mistake)_x000D_The Wiring Method is as Follows: _x000D_IN1-GND (default is high level, low level after the switch is turned on) The computer sends instructions to read the switch status._x000D_IN2-GND (default is high level, low level after the switch is turned on) the computer sends instructions to read the switch status._x000D_IN3-GND (default is high level, low level after the switch is turned on) the computer sends instructions to read the switch status._x000D_IN4-GND (default is high level, low level after the switch is turned on) the computer sends instructions to read the switch status._x000D_Board Resources: _x000D_1. S1 reset button_x000D_2. D5 running LED indicator_x000D_Control instruction into group sharing download_x000D_1. 4 relay outputs (one normally open, one normally closed)_x000D_2. STM8S103F3 MCU_x000D_3. 4 optocoupler isolation relay output_x000D_4. 4 relay closed LED indicators_x000D_5. Circular DC interface, and terminal DC interface. Convenient power connection (power supply voltage 5V or 12V depends on the voltage of the relay)_x000D_6. 4 input interfaces (dry node input, passive input, connected to GND)_x000D_7. One RS485 communication interface._x000D_8. A power indicator_x000D_9. One user LED light_x000D_10. Reset button_x000D_11. A SWIM download interface-(STLINK-V2 download program, users can develop the program twice)_x000D_1. Connect LED to user LED_x000D_2. TX RX connects to port 485 and pin header TTL port_x000D_3. KEY user button (red button on the left)_x000D_4. EN 485 use end_x000D_5. IN1 -IN4 input ports are directly connected to the terminals_x000D_6.K1 -K4 relay output control_x000D_7. SWIM programming program J13 _x000D_Size: Approx. 76 x 67mm / 3 x 2.6in 1This is a 4?channel 12V relay output board module. easy and convenient to install 2High quality material can make sure the durability and stability of the product 3The module has low power consumption, high accuracy, suitable for RS485 / TTL communication 4Adopted of high quality electronic components, and accuracy process, ensure for the durability 5The connecting part has good contact performance, ensure stable working1 x 4-Channel Relay Module