Applies To:
  • CitectSCADA 5.xx, 6.xx
  • CitectHMI 5.xx, 6.xx
Summary:
My test project shows that the Pageinfo(7) function does not increment once every page scan.

I tested the same page with different page scan rates, and regardless of whether I set the rate to 500, 1000, or 5000 it appears that the PageInfo(7) counter is incrementing at approximately 400 ms but the tags are still updating at the page scan of 500, 1000 and 5000 respectively.

The WhilePageShown Page Event also seems to increment at the same time as PageInfo(7).

Can you explain what is happening?

 

Solution:
PageInfo(7) returns the previous page display count. The count is incremented at each page refresh.
[Page]ScanTime can be modified to set different delay times between updating a page and starting the next communication requests.

There is a difference between obtaining and displaying tag values from units and updates from any executing cicode. Cicode will run once each page scan time but also run when its requests are fulfilled. This means current data is displayed at a greater rate than the [Page]ScanTime and is why the WhilePageShown Page Event is unlikely to be in synch with tag value updates.

PageInfo(7) is based on page animation count rather than page scan time. The PageInfo(7) display counter is incremented once every [Page]AnmDelay (default 500 ms) and once every [Page]ScanTime (default 250 milliseconds) provided the unit values are obtained this quickly.

 
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