Siemens SIMATIC PCS 7 CPU 410-5H System Manual page 310

Supplementary information
15.15 Cycle and response times of the CPU 410-5H
Longest response time
The figure below shows the conditions under which the longest response time is achieved.
Figure 15-33 Longest response time
Calculation
The (longest) response time is calculated as follows:
● 2 x process image transfer time of the inputs +
● 2 x process image transfer time of the outputs +
● 2 x operating system processing time +
● 2 x program processing time +
● 2 x delay of the DP slave frame (including processing in the DP master) +
● Delay of the inputs and outputs
This is equivalent to the sum of twice the cycle time and the delay in the inputs and outputs
plus twice the DP cycle time.
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CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB