Siemens S7-300 appendix Reproducibility of delay interrupts and watchdog interrupts

Cycle and reaction times 5.5 Interrupt response time

Process interrupt processing

Process interrupt processing begins after process interrupt OB40 is called. Higher-priority interrupts stop process interrupt processing. Direct I/O access is executed during runtime of the instruction. After process interrupt processing has terminated, cyclic program execution continues or further interrupt OBs of equal or lower priority are called and processed.

See also

Overview (Page 5-1)

5.5.2Reproducibility of delay interrupts and watchdog interrupts

Definition of "Reproducibility"

Delay interrupt:

The period that expires between the call of the first instruction in the interrupt OB and the programmed time of interrupt.

Watchdog interrupt:

The fluctuation width of the interval between two successive calls, measured between the respective initial instructions of the interrupt OBs.

Reproducibility

The following times apply for the CPUs described in this manual:

•Delay interrupt: +/- 200 μs

•Watchdog interrupt: +/- 200 μs

These times only apply if the interrupt can actually be executed at this time and if not interrupted, for example, by higher-priority interrupts or queued interrupts of equal priority.

CPU 31xC and CPU 31x, Technical data	5-23
Manual, Edition 08/2004, A5E00105475-05