Siemens SIMATIC S7-400 Reference Manual page 426

Diagnostic data of signal modules
B.5 Diagnostic data of the analog input modules as of byte 2
Byte 6
Byte 7
Bytes 8 to 23 of the SM 431; AI 8 x 16 bit
Data record 1 contains the channel-specific diagnostic data, starting at bytes 8 to 23. The
following table shows the assignment of the even diagnostic bytes (bytes 8, 10, to 22) for a
channel of the module.
Table B-27
Bytes 8-23
even
426
Byte Bit
7 Number of channels of the same type in one module: 8 channels
0
7 Channel error 7
6 Channel error 6
5 ......
4 ......
3 ......
2 ......
1 Channel error 1
0 Channel error 0
Even diagnostic byte for a channel of the SM 431; AI 8 x 16 bit
Byte Bit
7 Overflow
6 Underflow
5 Reference channel error
4 Wire break
3 0
2 0
1 0
0 Configuring/parameter assignment error
Meaning
Meaning
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08