User Manual of EM730 Series Inverter Chapter 11 MODBUS Communication Protocol 11.1 Applicable scope 1 、 Applicable series: EM730 series 2 、 Applicable network: Support the “single-master multi-slave” communication network with MODBUS-RTU protocol and RS-485 bus. 11.2 Interface 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] (options: 1-8-E-1, 1-8-O-1, 1-8-N-2, 1-8-E-2 and 1-8-O-2); 57600bps and 115200bps) Default baud rate of RS-485 terminal: 9600bps (options:
4800bps, 19200bps, 38400bps, 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: even parity. O: odd parity. 11.3 Protocol Format 11.3.1 Message format As shown in Fig. 12-20, a standard MODBUS message includes a start tag, RTU (Remote Terminal Unit) message, and end tag. 368