7 FBD/LD LANGUAGE
7.2 Program Execution Order
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7
Caution
■When using label
• Labels whose name ends with "_" cannot be used as an array index. To use such a device or label as an array index,
assign it to another device or label and specify that device or label as an index.
• Members of labels (structures or function blocks) whose name ends with "_" cannot be specified.
• Indexes cannot be specified to labels (arrays) whose name ends with "_".
7.2 Program Execution Order
The order of executions of program units
The order of executions of the units in the FBD/LD editor is determined depending on the positional relation of the units and
on the status of connecting wires.
The number of the order of the execution is shown on each unit placed on the FBD/LD editor.
CTD_E
EN
CD
LD
ENO
Q
PV
CV
Var_CU
Var_R
Var_PV
CTD_E_1
Var_Q
Var_CV
RETURN
M0
SM400
SM400
Y0
12
3
4
5
6
7
8
9
10
11
Executed from
the left side to
the right side
Executed from
the top to the
bottom
ADD
IN1
IN2
Var001
Var002
Var003
13
14
15
12