Corrected from:
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Response of the new version:
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What happens?
In some projects, the cycle times increase after updating the controller firmware to V1.7 or newer.
When does the behaviour occur?
In projects created for controllers c520/c550 with a firmware V1.6 or lower (see version of the device description), after updating the firmware in the controller from a version lower than or equal to V1.6 to V1.7 or higher, runtime extensions and thus watchdog exceptions may occur.
Affected are:
- Projects that contain many accesses to BIT variables (e.g. when accessing the process image of a Profinet card).
or
- Projects in which structures with many BIT variables are transferred via VAR_INPUT or VAR_OUTPUT.
Which products are affected?
Cabinet Controller c520 from V1.7
Cabinet Controller c550 from V1.7
Short-term measures:
For serial commissioning of existing projects, update the PLC projects with the current version of the PLC Designer via the project environment dialogue (menu 'Project' > 'Project environment') to a current status (<Set All to Newest>).
Evaluation / recommendations:
With increased use of BIT accesses in the PLC project, runtime increases may occur if the PLC project was created for a controller with a firmware V1.6 or smaller and this is now loaded in a controller with a firmware V1.7 or larger. This runtime increase can cause a task overflow. In this case, the PLC processing stops with an error message.
The use of the data type BOOL is not affected by this function restriction.
In general, it is recommended not to transfer large amounts of data via VAR_INPUT or VAR_OUTPUT to/from functions or function blocks, as this would result in time-consuming creation of copies of the data. Faster is the transfer via VAR_IN_OUT. Here, only references to the data are transferred.
Automatic Translation
