Different Cycle Times - Siemens SIMATIC S7-400H System Manual

S7-400 cycle and reaction times

16.3 Different cycle times

16.3 Different cycle times
The cycle time (T
different cycle times T
OB 1 is interrupted by a TOD interrupt OB (here: OB 10).
Figure 16-2
A further factor in different cycle times is the variable block execution time (e.g. OB 1)
caused by:
● conditional statements,
● conditional block calls,
● different program paths,
● loops etc.
Maximum cycle time
You can edit the default maximum cycle time (cycle monitoring time) in STEP 7. On expiration
of this time OB 80 is called, in which you can define the CPU's reaction to the timeout error.
Provided you do not retrigger the cycle time using SFC 43, OB 80 doubles the cycle time on
its first call. In this case the CPU goes into STOP on the second call of OB 80.
The CPU goes into STOP if there is no OB 80 in its memory.
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) is not of the same length for every cycle. The figure below shows the
cyc
and T . T
cyc1 cyc2
Different cycle times
is longer than T
cyc2 cyc1
System Manual, 09/2007, A5E00267695-03
because the cyclically executed
S7-400H