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7.4
Slave Diagnostics
7.4.1
Introduction
Errors such as "Sensor not found" trigger a slave diagnostic message. This is
according to the PROFIBUS standards EN 50170 and IEC 61158 / IEC 61784.
Depending on the DP master, it can be read out with STEP 7.
How to read out the slave diagnostic information and how it is structured is
described briefly below. You will find a detailed description in the Distributed I/O
Station ET 200M manual.
7.4.2
Reading Out the Diagnostic Information with S 7
If an error message such as "Sensor not found" occurs on the processing unit and
you are using an S7-CPU as the DP master, the diagnostic interrupt OB (OB82) is
started.
Its local variables OB_82_EV_CLASS, OB_82_MDL_DEFECT, and
OB82_EXT_FAULT can have the following values:
Variable
OB_82_EV_CLASS
OB_82_MDL_DEFECT
OB_82_EXT_FAULT
Unfortunately it is not possible to obtain the actual cause of the problem from the
local variables of OB82. You can, however, call SFC13 "DPNRM_DG" in OB82 to
obtain the cause.
Bytes 7 through 10 of the slave diagnostic information (diagnostic bytes 0 through
3) read with SFC13 correspond to the 32-bit long field "Unit_Diag_Bit" of the GSD
file SIEM8100.GSD.
The entry "Module fault" appears in the diagnostic buffer and the relevant text from
the GSD file is shown as the module status of the VS 130, for example "Sensor not
found".
Once you have eliminated the problem (in the example here, you have inserted the
sensor again) and acknowledged on the processing unit, the diagnostic interrupt
OB (OB82) is started again.
Vision Sensor VS 130
A5E00199459-01
Value
Meaning
B#16#39
Event entering state
TRUE
Module fault
TRUE
External error
Diagnostics
7-7
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