Applies To:
  • CitectSCADA 5.41, 5.42, 5.5, 6.0, 6.1, 7.0
  • CitectHMI 5.41, 5.42, 5.5, 6.0, 6.1, 7.0
Summary:

My trend pages only show trend data that has been flushed to disk on the trend server.  Data from the current time till the last flush does not display. 

Running TrnFlush("*") on the trend server causes the data to the current time to be viewable.
 
Most of my tags have a trend sample period of 30 seconds.  This causes them to flush to disk every 30 minutes.
For example, the following tag is trended with a 30 second sample time.  Current time is 11:48:26 AM.  Note that the most recent data displayed on the trend is at 11:27:34 AM.  There is a gap in the trend display from the current time to 11:27:34 AM.  It seems that the data from the current time to 11:27:34 is in memory in the trend server it just has not been flushed to yet.
 
 
 
This page is at 12:00:14 PM (~12 minutes later).  The 30 minutes worth of data has now flushed to disk and is viewable.
 
 

Solution:

The Trend Files may have become corrupted. 

Trend files with future data time stamps, due to changing your PC clock time into the future, may cause this type of corruption.

Also, changing the Trend Tag's "No Files" or the "Storage Method" from "Scaled (2-byte samples)" to "Floating Point (8-byte samples)" can cause Trend Data corruption. Please see the MyCitect Toolbox for tools on changing these fields without corrupting your data.  Antivirus Software can also corrupt your Trend data as it will lock the file for a scan while Citect is attempting to write to the trend file location.  It is suggest to exclude the Trend data folder from your antivirus software scans. KB Q3823 recommends less than 3000 files per Trend folder, so if you have more than 3000 files per trend folder it is suggested to segment these folders into smaller sizes.  This helps to avoid a large number of files located in 1 folder especially since the CitectSCADA Trend Server will create, delete, open, or close files quickly or frequently, thus it is a better solution is to logically separate the files into folders so that you can distribute the workload on multiple folders at a time.

Please contact Citect Support for further information and recommendations on recovering your corrupted Trend data.

 
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