WebRelay-10 Users Manual
Operation
Exception Codes (1 byte):
0x01 – Function not supported.
0x02 – Incorrect combination of start address and input quantity
Error Response Frame Example
Field Name
Length
Function
Example Data
Transaction Identifier
2 bytes
Synchronization between messages of
server and client.
0x0001
Protocol Identifier
2 bytes
Zero for Modbus/TCP
0x0000
Message Length
2 bytes
Number of bytes in frame (below)
0x0003
Unit Identifier
1 byte
Slave Address (0xff if not used)
0xFF
Function Code
1 byte
Error code
0x83
Data
1 byte
Exception code (
0x01 - 0x02
)
0x02
RX String: 00 01 00 00 00 03 FF 83 02
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