Bender ISOMETER isoRW425 - Exception Code; Structure of the Exception Code

Data access using the Modbus RTU protocol
47
isoRW425_D00052_03_M_XXEN / 02.2017
7.3 Exception code
If a request cannot be answered for whatever reason, the ISOMETER® will send
a so-called exception code with which possible faults can be narrowed down.
7.3.1 Structure of the exception code
Exception
code
Description
0x01
Impermissible function
0x02
Impermissible data access
0x03
Impermissible data value
0x04
Internal fault
0x05
Acknowledgement of receipt (answer will be time delayed)
0x06
Request not accepted (repeat request, if necessary)
Byte Name Example
Byte 0 ISOMETER® Modbus address 0x03
Byte 1 Function code (0x03) + 0x80 0x83
Byte 2 Data (exception code) 0x04
Byte 3, 4 CRC16 Checksum 0xE133