Rhymebus RM6F5 series, Operation Manual

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Chapter 8 Communication Description
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7-7 Communication Troubleshooting
1. When error occurs at the communication network, the drive provides the
self-testing function to identify where error occurs. Please check
communication function settings to verify the validity of functions.
2. When the host receives returned error messages from a drive, the host
sends the invalid operation command to drive. The following table is the error
message format.
Address OP Code Error Code
CRC Checksum
LSB MSB
02H 1xxxxxxxB xxH xxH xxH
OP code sets MSB (bit7) as 1 for the original command message, but error code
gives different values according to different types of errors. The below table is
describing types of error code:
Error
Code
Error Type Descriptions
0 0
Serial communication
format error
Parity error of serial communication
0 1 Data frame error of serial communication
0 2 Over-bit error of serial communication
0 3 Modbus OP code error OP code is not in either 03H,06H,08H, or 10H
0 4 Modbus CRC error CRC checksum error
0 5
Modbus data range
error
1. Data length in transmission not matched
with the protocol
2.
Data range over the register length at ―write‖
0 6
Modbus register
characteristics error
Registers writes into read-only registers
0 7
Modbus register error No-defined registers