Byte
Bit
Meaning
Byte 8
7
Channel error 15
6
Channel error 14
5
...
4
...
3
...
2
...
1
Channel error 9
0
Channel error 8
Bytes 9 and 24 of the SM 421; DO 16 x DC 20-125 V/1.5 A
Data record 1 contains the channel-specific diagnostic data, starting at bytes 9 to 24. The figure
below shows the assignment of the diagnostic byte for a channel of the module.
Table B-11
Diagnostic byte for a channel of the SM 422; DO 16 x DC 20-125 V/1.5 A
Byte
Bit
Meaning
Bytes 9 - 24
7
0
6
External load voltage missing
5
0
4
0
3
Short-circuit to M
2
0
1
0
0
Configuring/parameter assignment error
Bytes 2 and 3 of the SM 422; DO 32 x DC 24 V/0.5 A
Table B-12
Bytes 2 and 3 of the diagnostic data of the SM 422; DO 32 x DC 24 V/0.5 A
Byte
Bit
Meaning
Byte 2
7
0
6
0
5
0
4
Module-internal supply voltage failure
3
0
2
Operating mode 0: RUN; 1: STOP
1
0
0
0
Diagnostic data of signal modules
B.4 Diagnostic data of the digital output modules as of byte 2
S7-400 Automation System Module Data
414
Reference Manual, Ausgabe 11/2016, A5E00850736-08