Siemens Simatic S7-1500R - Product Overview; Mode Selector

Cyclic program execution
3.2 Cycle time
Cycle and response times
24 Function Manual, 10/2018, A5E03461504-AD
3.2
Cycle time
Definition of cycle time
The cycle time is the time the CPU needs for:
● Updating the process image inputs/outputs
● Executing the cyclic program
● All program parts and system activities interrupting this cycle
● Waiting for the minimum cycle time (if it is parameterized and is longer than the program
execution time)
3.2.1
Different cycle times
Introduction
The cycle time (T
cyc
) is not the same in each cycle because the processing times may vary.
Causes of this include:
● For example, different program runtimes:
– Program loops
– Conditional commands
– Conditional block calls
– Different program paths
● Lengthening due to interruptions, for example:
– Time-driven interrupt processing
– Event-driven interrupt processing
– Communication