Interruptions
Owing to the default, the TIMED INTERRUPTS layer has the highest
priority of the basic layers (can be modified in DX 0).
In time-controlled program execution, the execution of
clock-controlled interrupts has the lowest priority. This can therefore
be interrupted by the processing of a delayed interrupt or a cyclic
timed interrupt.
Special features
••
A clock-controlled interrupt is only processed in the RUN mode.
Clock-controlled interrupts occurring in the STOP mode, when
there is a power failure or during START-UP are discarded.
••
Once a clock-controlled interrupt has been generated (= OB 151
call has been processed) it is retained in a WARM RESTART and
following POWER DOWN/POWER UP; it is, however, deleted
during a COLD RESTART.
••
If you generate a new clock-controlled interrupt, i.e. call
OB 151 with new time values, a previously set clock-controlled
interrupt is cancelled. A clock-controlled interrupt currently
being processed is continued. This means that only one
clock-controlled interrupt is valid at any one time.
••
If a time-controlled interrupt occurs without the previous one
being completely processed, the clock time-controlled interrupt is
discarded. Clock-controlled interrupts are not checked for
collisions!
••
Note the special functions OB 122 and OB 142 with which you
can disable or delay the servicing of clock-controlled interrupts.
RUN Mode
CPU 948 Programming Guide
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C79000-G8576-C848-04
Summary of Contents for CPU 948
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Page 324: ...Examples of Parameter Assignment CPU 948 Programming Guide 7 18 C79000 G8576 C848 04 ...
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Page 370: ...Addressable System Data Area CPU 948 Programming Guide 8 46 C79000 G8576 C848 04 ...
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Page 522: ...PG Functions via the S5 Bus CPU 948 Programming Guide 11 38 C79000 G8576 C848 04 ...
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Page 538: ...Contents CPU 948 Programming Guide 13 2 C79000 G8576 C848 04 ...
Page 546: ...List of Key Words CPU 948 Programming Guide Index 6 C79000 G8576 C848 04 ...