Modbus water meter communication protocol

Modbus water meter communication protocol Introduction of RS485 module Four wires: RS485 needs four wires, of which the second wire is rs485a, rs485b, the second wire is positive and negative 12V power line, the pulse signal line is not divided into positive and negative poles, and the 485 communication line is connected. Red (12V positive), blue (12V negative), yellow (485a), green (485b). Note: wiring must be done carefully! An error will result in damage to the instrument