Cyclic Interrupt Ob With Special Handling - Siemens SIMATIC PCS 7 Operating Manual

Configuring S7F/FH hardware
6.2 Adapting CPU parameters (fault-tolerant F system)
6.2.2

Cyclic interrupt OB with special handling

Priority class
In order to prevent time monitoring (F-CYC_CO or the monitoring time of modules) from
being triggered in the event of a CPU that is starting up in the H system being
coupled/updated, you need to set the priority of the cyclic interrupt OBs allocated to the F-
program (OB 30 to OB 38) to > 15 on the "Cyclic Interrupts" tab (see Monitoring times).
"Cyclic interrupt OB with special handling" is an H parameter containing the number of the
cyclic interrupt OB which is called specifically by the operating system when the standby
CPU is updated, once all interrupts have been disabled. Here, enter the number of the cyclic
interrupt OB with the highest priority, to which F-blocks are assigned in CFC.
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Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB