Siemens SIMATIC BATCH Operating Manual page 72

Product introduction and installation
3.6 Configuration limits
Action
RESUME after HOLD command
PAUSE command
RESUME after PAUSE command
Close batch
Archive batch
Change parameter
Step change time
Result of the AS runtimes for AS-based mode
The measured results shown in the following table serve as the basis for the calculations made
below.
Recipe structure
Completing recipe phase (average measured value)
Updating setpoint (average measured value)
Processing a transition (average measured value)
Starting recipe phase (average measured value)
Processing a recipe phase (average measured value)
These measured values result in a step change time of 8.4 ms (1.8 ms + 5 * 0.07 ms + 4 ms
+ 1.9 ms + 5 * 0.07 ms) for a recipe phase with 5 parameters. As a result, with, for example,
100 simultaneously active recipe phases and 32 simultaneous step changes, the recipe
processing time can be calculated as follows:
Recipe processing time = 32 * 8.4 ms + 100 * 2 ms = 469 ms.
This calculation does not, however, apply to parallel branches, alternative branches or when
there is synchronization since more than three recipe objects are then involved in a step
change. 32 simultaneous step changes with such constructs would lead to a loss of
performance.
A reduction in the number of simultaneous step changes increases the number of
simultaneously active recipe phases and vice versa.
To guarantee optimum performance in the automation systems, remember the following:
● The calculated total cycle time (times for communication, firmware, recipe processing and
user program) should always be shorter than the cycle time of the OB in which the
UNIT_PLC and the user blocks are installed.
● Take into account all the CPU requirements relating to the cycle time (you should also refer
to the documentation for the automation system S7-400 CPU Data).
72
Runtime
< 2
< 2 s
< 2 s
5 to 10 min
< 50 s
< 3 s
4 s PC-based
< 1 ms AS-based
AS runtime
1.8 ms
0.07 ms
4 ms
1.9 ms
2 ms
SIMATIC BATCH V8.2
Operating Manual, 02/2016, A5E35958174-AA