4 PLC configuration
4.4 Task monitoring by watchdog
82 Modular PLCs XControl: XC-104-…, XC-204-…, XC-303-… 01/23 MN050005EN Eaton.com
Example: Watchdog deactivated
The interval time (IZ) is 10 ms.
Variant a: The interval time (IT) of a task was set to 10 ms.
The actual task time (TT) is 15 ms. The task is started on the first call but is
not terminated before the second cycle. Therefore, the task is not started
again in the second cycle. Only in the third cycle – after 20 ms – is it possible
to restart the task. The task does not run every 10 ms but rather only at a
time interval of 2 x 10 ms.
Variant b: The running cycle is not ended.
Figure 58: Watchdog deactivated
Multiple tasks with the same priority
You can assign several tasks with the same priority. The tasks are split
according to the “Time Slice” principle and are practically executed simulta-
neously as part intervals (Round Robin).
TZ > IZ
IZ
IZ IZ IZ
IZ
a TZ > IZ
b TZ > WZ
(endless loop)
TZ f WZ
TZ > IZ TZ > IZ
IZ = 10 ms
IZ
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