Applies To:
  • CitectSCADA 3.40 4.20

The [Page]Delay parameter has been replaced by the [Page]ScanTime parameter in version 3.40 and 4.20. 

The [Page]Delay parameter would put a small delay into the page update cycle. This delay would limit the maximum rate of update of the graphics pages to prevent overloading of CPU and network with very fast protocol drivers. However this delay was complex to understand and produced varying update times of different pages.

To simplify the setup the [Page]Delay parameter has been replaced with the [Page]ScanTime parameter. When you set the [Page]ScanTime parameter (default 250 ms), Citect will try to make the page update at this rate. For example if all the data is refreshed from the I/O server after 150ms and the [Page]ScanTime=250ms, then Citect will start the next update cycle in 100 ms. If it takes 350 ms for all data to be returned from the I/O server then the next update cycle will start immediately. This will give consistent rate of page updates.

For backward compatibly with projects which have adjusted the [Page]Delay parameter, Citect will add the delay time to the scan time. For example if you have [Page]Delay=1000 and [Page]ScanTime=250, then Citect will set the ScanTime to 1250 ms. So if you set the [Page]ScanTime you should delete the [Page]Delay parameter.

You may also adjust the ScanTime by calling the function PageSetInt(-2, <time>). Setting a new page scan time only effects the page where you called the PageSetIn() function. No other windows are effected and when you change to a new page the scan time will be set from the [Page]ScanTime parameter. You may get the current page scan time by calling PageGetInt(-2).