3.1 Basic Functionality
3.1.1 Programs
3-3
3
CPU Module Functionality
•
Hierarchical Configuration
There are four types of ladder drawings: parent drawings, child drawings, grandchild draw-
ings, and operation error drawings.
•
Parent Drawings
These drawings are automatically executed by the system program when the execution
conditions are met.
•
Child Drawings
These drawings are executed when they are called from a parent drawing with a SEE
instruction.
•
Grandchild Drawings
These drawings are executed when they are called from a child drawing with a SEE
instruction.
•
Operation Error Drawings
These drawings are automatically executed by the system program when an operation
error occurs.
A parent drawing cannot call a child drawing from a different type of drawing. Similarly, a child
drawing cannot call a grandchild drawing from a different type of drawing. A parent drawing
cannot call a grandchild drawing directly. The parent drawing first must call the child drawing,
and then the child drawing must call the grandchild drawing. This is called the hierarchical
configuration of drawings.
The following figure shows the parent-child-grandchild structure in which a program is cre-
ated.
U
s
er Function
s
Grandchild
Drawing
s
Child
Drawing
s
Parent
Drawing
Note:
= A, I, H, or L
DWG.
DWG.
01
DWG.
nn
DWG.
01.01
DWG.
01.02
FUNC-001
FUNC-006
FUNC-0
3
2
FUNC-064
DWG.
01.0
3
DWG notation:
Grandchild drawing number
Parent drawing type (A, I, H, or L)
Child drawing number
Note: The following notation i
s
u
s
ed for operation error drawing
s
.
Parent drawing type (A, I, H, or L) of the
drawing where the error occur
s
Fixed value (00)
DWG.
.
DWG.
00
