S7-400 cycle and response times
19.4 Communication load
S7-400H
368
System Manual, 03/2012, A5E00267695-11
Dependency of the actual cycle time on communication load
The figure below describes the non-linear dependency of the actual cycle time on
communication load. In our example we have chosen a cycle time of 10 ms.
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Figure 19-6 Dependency of the cycle time on communication load
Further effects on the actual cycle time
Seen statistically, the extension of cycle times due to communication load leads to more
asynchronous events occurring within an OB 1 cycle, for example interrupts. This further
extends the OB 1 cycle. How much it is extended depends on the number of events per
OB 1 cycle and the time required for processing these events.
Remarks
●
Change the value of the "communication load" parameter to check the effects on the
cycle time during system runtime.
●
Always take the communication load into account when you set the maximum cycle time,
otherwise you risk timeouts.
Recommendations
●
Use the default setting whenever possible.
●
Increase this value only if the CPU is used primarily for communication, and if time is not
a critical factor for the user program! In all other situations you should only reduce this
value!
Содержание SIMATIC S7-400H
Страница 24: ...Preface 1 1 Preface S7 400H 24 System Manual 03 2012 A5E00267695 11 ...
Страница 46: ...Getting Started 4 5 Special layout features of SIMATIC Manager S7 400H 46 System Manual 03 2012 A5E00267695 11 ...
Страница 120: ...Memory concept 10 1 Overview of the memory concept of S7 400H CPUs S7 400H 120 System Manual 03 2012 A5E00267695 11 ...
Страница 258: ...Communication 14 8 General issues regarding communication S7 400H 258 System Manual 03 2012 A5E00267695 11 ...
Страница 354: ...Synchronization modules 18 3 Selecting fiber optic cables S7 400H 354 System Manual 03 2012 A5E00267695 11 ...
Страница 434: ...Technical data 20 6 Runtimes of the FCs and FBs for redundant I Os S7 400H 434 System Manual 03 2012 A5E00267695 11 ...
Страница 460: ...Function modules and communication processors supported by the S7 400H S7 400H 460 System Manual 03 2012 A5E00267695 11 ...