Influences On Time Response - Siemens SIMATIC PCS 7 CPU 410-5H System Manual

Link-up and update
8.3 Time monitoring
8.3.4

Influences on time response

The period during which no I/O updates take place is primarily determined by the following
influencing factors:
● The number and size of data blocks modified during the update
● The number of instances of SFBs in S7 communication and of SFBs for generating block-
specific messages
● System modifications during operation
● Expansion of distributed I/Os with PROFIBUS DP (a lower baud rate and higher number
of slaves increases the time it takes for I/O updates).
● Expansion of distributed I/Os with PROFINET IO (a higher update time and higher
number of devices increases the time it takes for I/O updates).
In the worst case, this period is extended by the following amounts:
● Maximum cyclic interrupt used
● Duration of all cyclic interrupt OBs
● Duration of high-priority interrupt OBs executed until the start of interrupt delays
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CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB