Technical data

Basics of Designing a Program Structure
4.2 Blocks in the User Program
Programming with STEP 7
Manual, 05/2010, A5E02789666-01 101
Deactivating the Time-of-Day Interrupt
You can deactivate Time-Of-Day interrupts that have not yet been executed with SFC29
CAN_TINT. Deactivated Time-Of-Day interrupts can be set again using SFC28 SET_TINT and
activated with SFC30 ACT_TINT.
Priority of the Time-of-Day Interrupt OBs
All eight Time-Of-Day interrupt OBs have the same priority class (2) as default and are therefore
processed in the order in which their start event occurs. You can, however, change the priority
class by selecting suitable parameters.
Changing the Set Time
You can change the Time-Of-Day set for the interrupt as follows:
• A clock master synchronizes the time for masters and slaves.
• SFC0 SET_CLK can be called in the user program to set a new time.
Reaction to Changing the Time
The following table shows how Time-Of-Day interrupts react after the time has been changed.
If... Then...
you move the time ahead and one or more
Time-Of-Day interrupts were skipped,
OB80 is started and the Time-Of-Day interrupts that
were skipped are entered in the start information of
OB80.
you have not deactivated the skipped Time-Of-Day
interrupts in OB80,
the skipped Time-Of-Day interrupts are no longer
executed.
you have not deactivated the skipped Time-Of-Day
interrupts in OB80,
the first skipped Time-Of-Day interrupt is executed, the
other skipped Time-Of-Day interrupts are ignored.
you move the time back, the start events for the
Time-Of-Day interrupts occur again,
the execution of the Time-Of-Day interrupt is repeated
with S7-300-CPUs
and not
repeated for S7-400-CPUs and CPU 318.