Siemens SIMATIC S5 Manual page 214

S5-115F Manual
Reduce the intervals to a common time multiple. Optimize the call intervals to keep the
frequency of calls to a minimum.
Example:
30 ms Common time multiple
a all 150 ms User time updating
b all 30 ms Interrupt handling (OB 2) and time OB processing (OB 13)
c all 90 ms Programmer input processing
d all 120 ms SINEC L1 processing
a
b b b
b
c c c
c
d d d
d
BS 115F
FB 254 is called only six times.
Distribute the calls in your program in such a way that a call becomes effective at the latest
every 29 ms Note all paths along which the program can run.
Note
Take account of the call intervals defined here when you are setting the monitoring
times with COM 115F.
EWA 4NEB 811 6149-02
a
b b b
b
c
c
d
d
User program (6 calls)
a
a User time updating
b
b b
b Interrupt handling and
time-interrupt OB processing
c
c Programmer input processing
d
d SINEC L1 processing
Figure 6-3. FB 254 Calls (Final Schematic)
a
b b
b b
c c
d
a
b b b b
c
c
d
Blocks
a
b
c
d
t
BS 115F
t
t
t
t
6-13