Spontaneous Program Execution - Siemens CP-8000 User Manual

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If the cycle time is set to the value 0, no cyclic program execution takes place.
Under certain circumstances the cycle time can be changed independently by the system:
·
If no cycle time is set, it is set to 100 ms (default)
·
Extended due to timeout
·
Retriggering due to spontaneous program execution
Affecting the Processing Time
The processing time is the duration of a complete program run. It is primarily determined by
the size of the application program (number of operations).
Note
Consider that the processing time of the application program may be inconstant.
The processing time can be extended due to:
·
Number of communication connections (to further automation units, control system)
·
Number of I/O Modules on the TM-Bus
·
Conditional program calls
·
Diagnosis and error handling
·
Test- and commissioning functions such as status and simulation of inputs/outputs
·
Saving the application program (download)
·
Change of parameters online
The processing time of the application program is displayed on the user interface (online)
under PLC | Diagnosis .
Timeout
The processing time must not be greater than the cycle time. If the maximum processing time
successively exceeds 50% of the set cycle time five times, then the cycle time is increased by
50% independently by the system. Simultaneously an error information is set.

9.2.1.4.2 Spontaneous Program Execution

For faster reaction times, the application program can be executed spontaneous (event-
controlled). This must be defined in the startup part of the IL (PLC_RESET).
Possible events are:
·
Status change of a data point from the periphery
·
Status change of a data point from the communication
The spontaneous program execution is enabled in the IL by setting the variable PLC_SINGLE
to 1 (single run).
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Unrestricted SICAM A8000 / CP-8000 • CP-8021 • CP-8022 Manual
DC8-037-2.02, Edition 10.2017