User Manual of EM760 High-Performance Inverter Chapter 10 MODBUS Communication Protocol 10.1Applicable scope 1. Applicable series: EM760 series 2. Applicable network: Support the “single-master multi-slave” communication network with MODBUS-RTU protocol and RS-485 bus. Fig. 10-1 Schematic Diagram of Communication Network 10.2Interface mode RS-485 asynchronous half-duplex communication mode, with the least significant bit sent first; RS-485 network address: 1-247; 0 is the broadcast address; Default data format of RS-485 terminal: 1-8-N-1 [2] (1-8-E-1, 1-8-O-1, 1-8-N-2, 1-8-E-2 and 1- 8-O-2 are optional); Default baud rate of RS-485 terminal: 9600bps (options:
4800bps, 19200bps, 38400bps, 57600bps and 115200bps); It is recommended to use twisted-pair shielded cable as the communication cable to reduce the impact of external interference on communication. [2] : 1-8-N-1, meaning 1 start bit - 8 characters per byte of data - no parity - 1 stop bit. E: evenparity. O: oddparity. 10.3Protocol Format 10.3.1 Message format As shown in the figure below,a standard MODBUS message includes a start tag, RTU (Remote Terminal Unit) message, and end tag. 253