Blocks S5-115F Manual
Optimization of Call Frequency
Establish which functions you require frequently
Draw up a diagram of the PLC cycle and mark all calls
- on their individual axis and
- on a shared axis
Example:
The following are used for a PLC cycle time of 300 ms, (user program 200 ms, operating system 100
ms)
a every 160 ms User timer updating
b every 30 ms Interrupt handling (OB 2) and time OB processing (OB 13)
c every 100 ms Programmer input processing
d every 120 ms SINEC L1 processing
a
b
c
d
b cbb
BS 115F
t
t
30ms
t
t
t
bba
b
d
BS 115F
160 ms
User program (8 calls)
100 ms
120 ms
a User timer updating
c Programmer input processing
d SINEC L1 processing
a
b
c
d
b
c
d
b
c
d
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d
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d
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b Interrupt handling and
time-interrupt OB processing
Figure 6-2. FB 254 Calls (Ideal Schematic)
FB 254 is called 8 times per cycle.
6-12
EWA 4NEB 811 6149-02
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