Siemens SIMATIC S5-90U System Manual page 137

S5-90U/S5-95U
Longest Possible Response Time:
PII
PIQ
Operating
system
User
program
PII
Res-
ponse
PIQ
time
Operating
system
User
program
PII
PIQ
Operating
system
The (longest possible) response time is composed of the following:
• 3 x process image transfer time +
• 3 x operating system runtime +
• 2 x program execution time +
• Execution times for internal timers+
(This time is not shown in the diagram since the internal timers are updated at regular intervals
of 10 ms throughout the entire period under consideration.)
• Delay of the inputs and outputs
The input delay is also not marked in the diagram (see Appendix B, Technical Specifications -
Onboard I/Os or Section 15, Technical Specifications for the individual modules).
The delays for electronic outputs are negligible. When using relay outputs, you should take into
account the typical delay of 10 ms to 20 ms. The delay of the relay outputs depends, among
others, on the temperature and voltage. In the case of analog outputs, the conversion time for
the analog value must additionally be considered (sse Appendix B or Section 15).
EWA 4NEB 812 6115-02b
The status of the respective input changes while the PII is being
read. The input signal change is not taken into account in the PII.
The input signal change is now entered in the PII.
The input signal change is processed by the user program.
The response of the user program to the input signal change is
written to the outputs.
(Please note that the units surrounded by a broken line represent
sections that are not available for user program execution.)
Addressing and Access to I/Os
6-17