Festo CECX-X-C1 Series, Manual

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CECX modular control system
Information on application
The cycle time for the motion task is configured depending on the used drives. If you use
CMMS-AS, CMMS-ST, SFC-LAC oder SFC-LACI the minimal cycle time is 8 ms.
For more information see the systemdescription of the drives.
Unused [SLOT]
Not used at the moment.
Notes on system behavior
The system behavior can, in certain cases, be influenced via application programming e.g. for:

Watchdog exception
Watchdog exception
A watchdog exception occurs when during a task in CoDeSys it is determined that the current cycle of the
maximum allowed time according to task configuration has been exceeded. This leads to the watchdog
exception callback of the Iec application being executed.
The system stops the task in which the exception has occured and the execution of al assigned
programms. The tasks subsequently execute no further cycle until an application reset was performed.
Other tasks of the taskconfiguration are not stopped. When the whole application is stopped, a start is only
possible after an application reset.
If a reaction is desired from the user, a watchdog exception handler must be added (Task configuration-
>System events):
The system behavior can be influenced as desired in this e.g. by call of a callback function. The name of
the called function must begin with "callback".
The behavior for a watchdog exception must be considered with the application design, e.g.:
switching from automatic to manual mode or reboot of the control. It is dependent on the
device function and the effects which the failure of the affected task can trigger.
The called callback function may not contain long continuing procedures (e.g. writing of files,
etc.) since otherwise the control will be totally blocked.
If a task with assigned programmcall is not defined in the project, a default task (realtime,
priority 10) with 10 ms cyle-time and active watchdog (time: t#11ms / sensitivity: 1) is used.
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