Automatic control function programming manual ladder language

Operation of the Background Tasks
NOT READY —> READY
Structure of an Application
When the system is reset, tasks %TF are in NOT READY state. The call to function tfstart(n) causes %TFn to go into
READY state.
WAITING or READY or RUNNING —> NOT READY
The call to function tfstop(n) causes task %TFn to go into NOT READY state.
READY —> RUNNING
In READY state, a task %TF is executed as soon as no task is RUNNING and no %TF task with higher priority is in
READY state.
The hierarchy of tasks %TF is determined by their number:
RUNNING —> SUSPENDED
%TF0 priority > %TF1 priority > ... > %TF15 priority
Task %TF is suspended to allow execution of a task %TS or %TH. Tasks %TF are not mutually preemptible.
SUSPENDED —> RUNNING
When no %TS or %TH task is running, the suspended %TF task is resumed.
RUNNING —> WAITING
Task %TF calls function whtr() or ends (end of task reached).
REMARK Function whtr(..) programmed in a background task interrupts the task during
execution to allow the execution of other %TF tasks in READY state.
WAITING —> READY
The task was placed on wait by function whtr(..) for a given number of RTC cycles which have now elapsed.
The task is completed, and the occurrence of the RTC returns it to READY state.
en-938846/3 2 - 7
2