Siemens Simatic S7-1500 Function Manual page 47

Cyclic program execution
3.5 Summary of response time with cyclic and time-controlled program execution
Estimation of the longest response time
The longest response time is the sum of:
1 x delay of the input/output module for inputs
+ 2 x (update PROFINET IO or PROFIBUS DP)*; (update time of the backplane bus for the
ET 200SP CPUs)
+ 2 x transfer time of the process image input
+ 2 x execution of the user program
+ 2 x transfer time of the process image output
+ 2 x (update PROFINET IO or PROFIBUS DP)*; (update time of the backplane bus for the
ET 200SP CPUs)
+ 1 x delay of the input/output module for outputs
_________________________________________________________________________________
= Longest response time
* Time is dependent on the configuration and the extent of the network.
The longest response time is equivalent to the sum of twice the cycle time plus the delay
times of the inputs and outputs. Twice the update time for PROFINET IO or twice the DP
cycle time on PROFIBUS DP is added to the longest response time.
46
Cycle and response times
Function Manual, 10/2018, A5E03461504-AD