Siemens SIMATIC ET 200AL, System Manual

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High-speed analog modules
8.1 Basics
Analog value processing
116
Function Manual, 06/2014, A5E03461439-AC
Cycle time of an analog input module
If you have configured the system property "Isochronous mode" for HS modules, all analog
input modules are synchronized to a shared time within the send clock (cycle)
①
. The cycle
time is made up of the following time intervals: t
Z
= t
1
+ t
2
+ t
3
+ t
4
①
Synchronization time for all analog input modules in isochronous mode and simultaneously
time of the converted input signal at the terminal in this cycle
②
Digitalized input signal is transferred to the backplane bus
t
Z
Cycle time
t
1
Time between cycle start and synchronization
t
2
Hardware-related runtime up to the analog-digital converter
t
3
Processing time of digitalized input data in the module
t
4
Transfer time of the backplane bus
t
W
Conversion time of the module
Figure 8-3 Cycle time of the analog input module