Lenze PROFINET Controller-based Automation - Manual (Page 34)

8 Defining the cycle time of the PLC project
8.1 Determining the task utilisation of the application
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Lenze · Controller-based Automation · PROFINET® Communication Manual · DMS 1.2 EN · 04/2014 · TD17
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How to determine the task utilisation:
Initial situation: A complete project, e.g. with a PROFINET task and 2 lower priority tasks has
been created.
1. For a first measurement of the task utilisation, set the cycle times of all cyclic tasks
available in the PLC system "high" (e.g. PROFINET task = 10 ms, all other cyclic
tasks = 20 ms).
2. Use the menu command Online  Login, or log in on the Lenze controller with <Alt>+<F8>.
With the log-in, the I/O device configuration is loaded into the controller.
3. Reset the values displayed on the Monitor tab of the Task Configuration to 0 after the
complete run-up of the system.
Execute the Reset command from the context menu of the task name field.
4. Read the displayed maximum computing time of the task with the highest priority.
In the illustration above, the max. cycle time of the PROFINET task is 399 μs.
The task cycle time does not have to be faster than the set PROFINET cycle time.