Different Cycle Times - Siemens SIMATIC S7-300 Manual

Cycle and response times
7.2 Cycle time
7.2.3

Different cycle times

Overview
The length of the cycle time (T
different cycle times, T
OB 1 is interrupted by a time-of-day interrupt OB (here, OB10).
PIO
Figure 7-2
Block processing times may fluctuate
Fluctuation of the block processing time (e.g. OB 1) may also be a factor causing cycle time
fluctuation, due to:
• Conditional instructions,
• Conditional block calls,
• Different program paths,
• Loops, etc.
Maximum Cycle Time
STEP 7
In
called, and in it you can define how you want the CPU to respond to the time error.
The CPU switches to STOP mode if OB80 does not exist in its memory.
7-6
and T
cyc1
T
PIO
PII
Different cycle times
you can modify the default maximum cycle time. If this time has expired, OB 80 is
) is not identical in each cycle. The following figure shows
cyc
. T is longer than T
cyc2 cyc2
PII
-
OB OB
, because the cyclically scanned
cyc1
PIO
S7-300 CPU Data: CPU 315T-2 DP
Manual, 12/2005, A5E00427933-02