Siemens SIMATIC S7-400H System Manual page 372

S7-400 cycle and response times
19.5 Response time
Longest response time
The figure below shows the conditions under which the longest response time is achieved.
Figure 19-9
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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Longest response time
System Manual, 03/2012, A5E00267695-11
S7-400H