Siemens Simatic S7-400 - Manual (Page 584)

Diagnostic Data of the Signal Modules
B-10
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Bytes 2 and 3 of the SM 422; DO 32 24 VDC/0.5 A
Byte 2
7 6 0
Operating status 0: RUN
1: STOP
Module-internal supply voltage failure
5 4 3 2 1
0
Byte 3
7 6 0
EPROM error
5 4 3 2 1
0
0 0 0 0 0
0 0 0 0 0 0
Figure B-11 Bytes 2 and 3 of the Diagnostic Data of the SM 422; DO 32 x 24 VDC/0.5 A