Siemens SIMATIC IM 151/CPU User Manual

Cycle and Response Times
7-8
ET 200S Interface Module IM 151/CPU
A5E00058783-01
Longest Response Time
The following figure shows what the longest response time consists of.
Operating
system
User
program
PII
While the PII is being read in, the status of
the observed input changes. The change in
the input signal is no longer taken into
account in the PII.
PIQ
The change in the input signal is taken
account of in the PII here.
The change in the input signal is processed
by the user program here.
The response of the user program to the
input signal change is passed on to the
outputs here.
Response Time
Delay of the inputs
Delay of the outputs
Operating
system
User
program
PII
PIQ
Figure 7-3 Longest Response Time
Calculation
The (longest) response time consists of the following:
 2  process image transfer time for the inputs +
 2  process image transfer time for the outputs +
 2  operating system processing time +
 2  program scanning time +
 Processing time of the S7 timers +
 Delay of the inputs and outputs
This corresponds to the sum of the doubled cycle time and the delay of the inputs
and outputs.

Siemens SIMATIC IM 151/CPU Specifications

General

Brand	Siemens
Model	SIMATIC IM 151/CPU
Category	Control Unit
Language	English