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Siemens Simatic S7-400 User Manual

Page 578

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Diagnostic Data of the Signal Modules

B-4

S7-400, M7-400 Programmable Controllers Module Specifications

A5E00069467-07

B.3

Diagnostic Data of the Digital Input Modules

as of Byte 2

The structure and contents of the different bytes of the diagnostic data for special
digital input modules are described below. The following general rule applies:
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 called “Diagnostics of the Modules”.

Bytes 2 and 3 of the SM 421; DI 16

24 VDC

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

Hardware interrupt lost

5 4 3 2 1

0

0

0 0

0

0

0 0 0

0 0

Figure B-2

Bytes 2 and 3 of the Diagnostic Data of the SM 421; DI 16 x 24 VDC

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