6. Modbus Communication Protocol
EM-GU User’s Manual
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6. Modbus Communication Protocol
6.1 About Modbus RTU protocol
series soft start provides RS485 communication interface and supports Modbus-RTU slave communication
protocol, users can achieve centralized control through the computer or PLC.
Electrical interface:
RS485
Half-Duplex Mode
Communication parameter:
Baud rate: 9600, 8 bits, No parity bit, 1 stop bit.
Communication data format:
Data format
Address
Function Code
Data Area
CRC Verify
Length of the Data
1 byte
1 byte
N bytes
2 bytes
6.2 Bus Structure
6.2.1 Support Code
Soft starter only supports following code, if other codes were used, there will feedback messy code 01.
Code
03
06
Function description
Read register
Write in one register
代码
03
只能用单字（
WORD
）读取
6.2.2 Address Definition
Addresses corresponding to parameters:
Parameter Code
Address
F00~F50
0x0000~0x0032
Control command input:
Address
Command function
0x0196
0001: Start
0002: Reserved
0003: Stop
0004: Fault reset
Read soft starter state:
Address
Command function
0x0050
0000: Ready state
0001: Starting state
0002: Running state
0003: Stopping state
0005: Fault state
Read soft starter fault state:
Address
Name
Soft starter fault information
0x0051
Current fault record
0: No fault
80: No fault
81: Input phase failure
82: Input phase failure
83: Output phase failure
84: Output phase failure
8A: Over heat
8B: Over voltage
8C: Under voltage
8D: Reserved
8E: Reserved
8F: Reserved
0x012C
1
st
fault record
0x012D
2
nd
fault record
0x012E
3
rd
fault record
0x012F
4
th
fault record
0x0130
5
th
fault record
