Overview
In case of Save mode, save will be done at the end of the processing
of every chart.
If a change of the active steps of a chart occurs, the new StepIDs (internal identifier) are stored to the memory and a status is memorized.
This is repeated for all SFC sections following in the scan.
At next execution of the EFB, the cumulated status of save operation is retrieved and shown at the output.
If more than 1 error is detected, the most significant one (see STATUS Error Messages) will be displayed.
Effects of Modifying the Application
If the application is modified (adding, deleting, moving or disabling SFC sections), this will influence the saved data.
Modification |
Effect |
|---|---|
adding an SFC section |
Active steps are immediately saved when section is executed. |
deleting an SFC section |
No more save, data in memory is removed. |
moving an SFC section |
Data will be stored in different order. |
disabling an SFC section |
No more save, but data is still valid. Saved again if enabled. |
Checksum
It will be checked whether the data fits into memory space according to user settings (number of SFC sections and number of active steps per SFC section).
A checksum is created for each section and will provide a certain security, that content is not damaged.
Update of Stored Data
If SFC sections are not executed because execution condition is false, the StepIDs (internal identifier) of the last execution are still available.
If executed again, the StepIDs will be updated.
Newly added SFC sections will store their StepIDs as soon as they are executed.
Stored data of deleted SFC sections will be immediately deleted.
In general after a build/change all data are invalidated as they are not usable because of changed application signature. This avoids memory shortage due to obsolete data.
In this environment, a restore after a CPU failure is probably a mix of chart data of 2 scans, as the CPU failure most likely will occur somewhere within the scan.