Component Parts Of The Cycle Time - Siemens SIMATIC ET 200S Manual

Cycle and Response Times
9.1 Cycle time
Cycle time – a definition
The cycle time is the time that the operating system requires to process a program
cycle – i.e. an OB 1 cycle – as well as all the program sections and system
activities interrupting this cycle.
This time is monitored.
Components of the cycle time
Operating system execution time
Process image transfer time (PII and
PIQ)
User program execution time
Loading through interrupts
The following figure shows the components that make up the cycle time:
Acyclic user
program (e.g. OB
40/82)
Figure 9-1
9-2
Factors
Operating
system
Interrupts

Component parts of the cycle time

Remarks
See Table 9-1
See Table 9-2
Is calculated from the execution times of the
individual instructions and a CPU-specific factor
(see Table 9-3).
See Table 9-4
PII
Operating
system
Cyclic user program
(OB 1)
PIQ
ET 200S IM 151-7 CPU Interface Module
A5E00058783-04