Siemens SIMATIC TI500 - Code 07 - Read Exception Status; Read Exception Status Example - Request; Read Exception Status Example - Response

Modbus Commands
C-15
TIWAY I Gateway User Manual
Code 07 instructs the Gateway to read 8 predefined Cs within a secondary .
This implementation will read the first 8 Cs in the discrete image register in
a secondary and pack them into one data byte.
NOTE: The programmer of a non-Modbus PLC must make certain that the
application program running within the PLC will place meaningful data in
these locations. This data can reflect status information.
Example:
I000000
Request: 11 07 XXXX
Checksum (XXXX)
Function code (07)
Slave address (11)
Figur e C-17 Read Exception Status Example — Request
This request to secondary 17 (decimal) is asking for exception status data.
I000000
Response: 11 07 3B XXXX
Checksum (XXXX)
Data value (3B)
Function code (07)
Slave address (11)
Figur e C-18 Read Exception Status Example — Response
Code 07 — Read
Exception Status