Every OB 82 call causes an entry in the diagnostic buffer of the CPU
containing error cause and module address. By using the SFC 59 you
may read the diagnostic bytes. At de-activated diagnostic interrupt
you have access to the last recent diagnostic event. If you've acti-
vated the diagnostic function in your hardware configuration, the con-
tents of record set 0 are already in the local double word 8 when
calling the OB 82. The SFC 59 allows you to also read the record set
1 that contains additional information. After leaving the OB 82 a clear
assignment of the data to the last diagnostic interrupt is not longer
possible. The record sets of the diagnostic range have the following
structure:
Byte Bit 7...0
0
n Bit 0: set at module failure
n Bit 1: 0 (fix)
n Bit 2: set at external error
n Bit 3: set at channel error
n Bit 4: set when external auxiliary supply is missing
n Bit 7 ... 5: 0 (fix)
1
n Bit 3 ... 0: Module class
–
0101b: Analog
– 1111b: Digital
n Bit 4: Channel information present
n Bit 7 ... 5: 0 (fix)
Example:
Diagnostic interrupt
processing
Record set 0 Diag-
nostic
incoming
VIPA System 300S Deployment I/O periphery
Counter - Diagnostic and interrupt > Diagnostic interrupt
HB140 | CPU | 314-6CF03 | GB | 16-43 173
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