For the same time point, faster cycle times are executed first.
A function block that is placed after a function block in the
execution flow must have the same or a higher cycle time and/or
execution order. See Figure 38.
IEC09000615 V2 EN-US
Figure 38: Cycle time and execution order
A function block type can be defined to be a member of one or several cycle times.
A function block instance can be set only to one cycle time.
IEC08000271.vsd
Execution order
group 1
Execution order
group 2
Execution order
group 3
Execution Flow
IEC08000271 V1 EN-US
Figure 39: ACT: Concept of Execution order sequence
In the conceptual MainApplication example in Figure 39, the execution order of
the main function block in the execution order group 2 defines the execution orders
needed in group 1 and 3. The preceding logic done with function blocks in group 1
must have a lower execution order than the ones in group 2. The following function
Section 6 1MRK 511 398-UEN C
Protection and control engineering
74 670 series 2.2 IEC
Engineering manual
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