Response Time Of R/H Cpus - Siemens Simatic S7-1500 Function Manual

Cycle and response times of the S7-1500R/H redundant system

5.4 Response time of R/H CPUs

5.4 Response time of R/H CPUs
Relationship between the cycle time and response time
The cycle time of the system also forms the basis for its response time. The response time
depends, among other things, on the cycle time of the individual program cycles.
Fluctuation of the response time
The actual response time fluctuates between one and two cycles during cyclic program
execution. The actual response time fluctuates between one and two cyclic interrupt cycles
for time-controlled program execution.
You should always assume the longest response time when configuring your system.
In the figure below the process image is updated immediately after the change of the
encoder signal. The output can therefore respond to the signal change after a cycle has
ended.
①
Synchronization of the encoder signal change in the backup CPU
②
Time lag of the backup CPU to the primary CPU
③
Synchronization of the output signal change in the backup CPU
④
Time lag of the backup CPU to the primary CPU until actual output of the signal change to the IO devices in the
PROFINET ring
Figure 5-6 Shortest response time
66
Cycle and response times
Function Manual, 10/2018, A5E03461504-AD