Fanuc C-Executer Operating Manual
B-62443EN-3/03E
- 895 -
5.1.2.3 When are each tasks executed ?
(1) CNC interruption tasks
They are waked and executed by timer interruptions without relation to
the currently displayed screen.
(2) CNC display task
It is executed while any CNC screens are being displayed. Even while user
screen is displayed, it is also executed sharing the CPU time with the user
tasks.
(3) User main task
It is executed only while any user screens are being displayed.
(4) User background tasks
They are waked by the events and executed without relation to the
displayed screen.
After power is ON, following tasks are waked in the order listed below, next
to the CNC's power on task.
CNC interruption tasks
Alarm task
Communication task
Main task
CNC display task
The communication task and the main task is waked after the alarm task and the
communication task, respectively, calls the first function which waits for
events. It is after the screen display is switched from user screen to the CNC
screen that the CNC display task starts displaying.
5.1.2.4 Task switching time chart
The following are conceptual descriptions. Actually the timer interruptions
which wake the CNC interruption tasks occur much more frequently.
(1) While CNC screens are being displayed. (without user background tasks)
CNC INT |******| |******| |******|
| | | | | |
| | | | | |
CNC DISP //----| |-------| |-------| |----//
Timer INT //----^--------------^--------------^-----------//
The CNC interruption tasks are waked by the timer interruptions which start
the CNC interruption tasks. The CNC display task is executed while no CNC
interruption tasks are being executed.