Yaskawa MP920 User's Manual Design - Manual (Page 86)

3 Basic System Operation
3.4.2 Execution Control of Parent Drawings
3-12
„ Execution Scheduling of Scan Process Drawings
The scan process drawings are not executed simultaneously. As shown in Fig. 3.3, they are
scheduled based on the priority level and are executed according to the schedule.
* Used for internal system processes, such as self diagnosis.
Fig. 3.3 Execution Scheduling of Scan Process Drawings
The low-speed scan process is executed in the unused time of the high-speed scan process. Therefore,
as a guideline, set a time that is twice the execution time of all the DWG.H drawings as the high-speed
scan time.
„ Hierarchical Arrangement of Drawings
Drawings are arranged in the following order: Parent drawing, child drawings, grandchild
drawings. A parent drawing cannot call a child drawing of a different type, and a child draw-
ing cannot call a grandchild drawing of a different type. A parent drawing also cannot
directly call a grandchild drawing. A child drawing is called from a parent drawing, and a
grandchild drawing is called from that child drawing. This is called the hierarchical arrange-
ment of drawings.
: Executed
High-speed
scan
High-speed
scan
High-speed
scan
High-speed
scan
Low-speed scan
DWG.H
DWG.L
Ground*
IMPORTANT