Applies To:
  • CitectSCADA 5.x, 6.x, 7.x
Summary:
I have just configured new trends in my system.

When I restarted my trend server, I saw that my trend files were created. However, I cannot display any data on my trend page (n/a values are reported), and my trend files do not seem to contain any numeric data.

I know that the problem is with my trend server, as I can display the variable tag value on a page without any problem.

 

Solution:
If your server is configured as a Trend Server, the problem may be because of your variable tag configuration.

If you did not specify any raw or engineering scale values for the variable tag that you are trying to trend, the trend tag will default to an engineering scale of 0-32000. This is by design.

This means that if the variable tag value is below 0 or above 32000, no data will be recorded in the trend files, this resulting in n/a values being displayed.

For this type of trend tag, you therefore need to make sure that you do not leave your variable tag's scale values empty.

The Trend tag engineering scales will then match the ones of the variable tag.

 

Please read KB Q3960 for further information.

 
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