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B8976111/02
3.3.2.3 Sequence of Diagnostic Interrupt Servicing
If the CP 142-2 detects an interrupt event, it triggers a diagnostic interrupt. The BM147 checks the
source of the interrupt and reads data record 0 from the CP. Following this, it interrupts the cyclic
user program and behaves as follows:
If OB82 is not programmed, the BM147/CPU changes to STOP (default setting).
±
If OB82 is programmed, it is started. Data record 0 is available in the local data bytes 8 to
±
11 of the local data area of OB82. Data record 1 containing the delta list can (but does
not need to be) read in OB82 using an SFC call (SFC59 "RD_REC"). On completion of
OB82, the BM147 acknowledges the diagnostic interrupt on the CP 142-2.
If interrupt events occur in a state in which this cannot be signaled by triggering a diagnostic interrupt
(for example when BM147 is in the STOP mode or when an older diagnostic interrupt has not yet
been acknowledged), the CP 142-2 behaves as follows:
A diagnostic interrupt can be triggered again and when the current entire CP
±
configuration (in other words AS-i slave configuration and internal CP state relevant to
the interrupt) is not the same as the configuration signaled previously with the diagnostic
interrupt, a diagnostic interrupt with current configuration information is signaled.
If triggering of a diagnostic interrupt becomes possible again and if the current entire CP
±
configuration is the same as the configuration signaled previously by the diagnostic
interrupt, no diagnostic interrupt is signaled. This means that brief slave failures (for
example caused by a faulty contact) may not be indicated in some circumstances.
3.3.2.4 Response to Interrupts in Various CP States
The CP 142-2 generates diagnostic interrupts only in the protected mode and not in the configuration
mode. (Exception: internal hardware fault, for example EEPROM defective)
When the BM147 changes to STOP, the interrupt history is reset, in other words bit
OB82_MDL_DEFECT and all other error bits in data record 0 are reset.
When the module changes from the protected mode to the configuration mode, the interrupt history is
also reset. If the CP changes from the configuration mode to the protected mode and if a
configuration error exists at this time, this is indicated by a diagnostic interrupt. If the signaling of a
diagnostic interrupt is temporarily not possible (for example because the PLC is in the STOP mode),
a diagnostic interrupt is only generated at the next possible point in time when the error still exists.
3-11
AS-i Master Module CP 142-2
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