B.3
Diagnostic data of the digital input modules as of byte 2
Overview
The structure and contents of the different bytes of the diagnostic data for special digital input
modules are described below. General rule: When an error occurs, the bit concerned is set to
"1".
You will find a description of possible error causes and appropriate remedies in the section
"Diagnostics of the modules".
Bytes 2 and 3 of the SM 421; DI 16 x DC 24 V
Table B-3
Bytes 2 and 3 of the diagnostic data of the SM 421; DI 16 x DC 24 V
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
Byte 3
7
0
6
Hardware interrupt lost
5
0
4
0
3
0
2
EPROM error
1
0
0
0
Diagnostic data of signal modules
B.3 Diagnostic data of the digital input modules as of byte 2
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
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