Cpu 410 Cycle And Reaction Times; Cycle Time - Siemens SIMATIC CPU 410 System Manual

An overhead is only required if you operate modules from the following table as redundant
modules.
Table 18- 8
Module type
ET200M: Standard output modules
ET200M: HART output modules
ET200M: F-output modules
Follow the steps below:
● Calculate the overhead from the table. If you use several module types from the table
redundantly, apply the largest overhead.
● Add this to all of the monitoring times calculated so far.
18.16

CPU 410 cycle and reaction times

18.16.1

Cycle time

This chapter describes the decisive factors in the cycle time, and how to calculate it.
Definition of cycle time
The cycle time represents the time that the operating system needs to execute a program,
that is, one OB 1 cycle, including all program sections and system activities interrupting this
cycle.
This time is monitored. The CPU 410-5H has a fixed cycle monitoring of 6 seconds.
Time slice model
Cyclic program processing, and therefore also user program processing, is based on time
slices. To demonstrate the processes, let us presume a global time slice length of exactly 1
ms.
Process image
During cyclic program execution, the CPU requires a consistent image of the process
signals. To ensure this, the process signals are read/written prior to program execution.
During the subsequent program execution, the CPU does not access the signal modules
directly when addressing the input (I) and output (O) address areas. It accesses the CPU's
system memory area containing the image of the inputs and outputs.
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
For the monitoring times with redundant I/O
Supplementary information
18.16 CPU 410 cycle and reaction times
Overhead in ms
2
10
50
357