Applies To:
  • CitectSCADA x.x

Question: I have a problem with the trend history data. Trend data is saved well on the file server during a month. But after a month, It is eliminated and saved newly. There is no historical data, at the first day of each month. I can't figure out what is going on with this situation? 

When a trend history file becomes full that file is rolled over into history and a new file is created. When you configure the trend tag you specify the number of trend history files to have. The default is 2 files so that you have one history file and one active file. If you specify 1 history file then when the file becomes full it will be rolled over into history, the new history file will be created and the history file with the last data will be deleted. This will give the effect that you have your trend history data until the maximum time of the file (I assume one month in your case). When the new month occurs the file will roll over and you will have no history data.

To solve this problem always set the No. Files to at least 2 in the trend tag definition.