Citect SCADA 7.20 – Trend Only Showing Real-Time, No Historical Data.

Hi Sasin Kitsawas 

What page / trend view object are you using to display the Trend data? Process Analyst or legacy Trend object on a Page?

Is the Trend Server running? 

It sounds like you are using Process Analyst, since it is displaying Real Time Data (likely coming from the Variable Tag directly).

Try running the Example project and see if the same issue occurs.

As Patrick mentioned, v7.20 is long out of support. It is recommended to upgrade to the latest version "2023 R2".

Kind regards

Olivier

Thanks Olivier for your response.

Yes — I'm using Process Analyst to display the Trend data.

The Trend Server is running correctly. However, the issue happens when I close and reopen Runtime — the historical data from the previous session does not show up in the trend display. It only shows real-time values after Runtime is restarted.

I also tried running the Example project, and I did **not** encounter the issue there. So it seems to be specific to my project.

That said, I have already reviewed and matched the Trend Tag settings with those in the Example project, but the issue still persists.

Do you have any idea what else I should check? Could there be any setting outside the Trend Tag itself that affects historical logging or data retention?

Thanks again!

I’ve also attached a screenshot comparing the configuration between the Example project and my own project.

From what I can see, the settings for the Trend Tag and related components look identical.

Still, the issue only happens in my project — historical data is not showing after restarting Runtime.

Any suggestions are very welcome!

Hi Sasin,

Open the properties panel up in Process Analyst at runtime.

1. Click on each of the Pens.
2. Check if the "Instant Trend" checkbox is checked or not on Connection Tab. (See screen shot)

If it is checked, then the Process Analyst is looking for "Cluster1.Bottler_Tank1_Level" Variable tag - no history.
If it is unchecked, then the Process Analyst is looking for "Cluster1.Bottler_Tank1_Level" Trend tag - will have history.

Thanks for the suggestion!

I checked and found that the "Instant Trend" checkbox was ticked. I tried unchecking it as you recommended, but when I did that, the data no longer appeared on the trend at all — even real-time values didn’t show.

It seems like the system is only able to show data when it's using Instant Trend (i.e., from the Variable Tag), and when I switch to the Trend Tag, nothing appears.

Could this indicate that my Trend Tag isn’t logging properly, or is there anything else I should check?

Use the "Add Pen" button on the process Analyst, this will then allow you to browse the tags based upon Trend, Variable etc. 

Select one of the Trends, and add that. The history will show within a second or so.

Remember, Citect/Plant SCADA has different tags for the variable and the trend(s) associated with it. They can also have different names. So in your case, you may have a variable tag called "RO_SUPPU_FT01" but you trend tag maybe called something different - thus you cannot just tick/untick. You need to put in an actual trend tag from your project - and make sure the Instance Trend checkbox is unchecked. The Add Pen dialog does all this for you automatically.

Hi Sasin,

Your trend tag is configured incorrectly for your purpose. 

The period is set to "00:01:00" which means 1 minute of data is stored starting at 24:00:00 for 10 files, so your historical data only applies for 10 minutes a day.

Set it to eg 24:00:00 to have 10 days of history.

BR ,
Erik

Hi Sasin,

Your trend tag is configured incorrectly for your purpose. 

The period is set to "00:01:00" which means 1 minute of data is stored starting at 24:00:00 for 10 files, so your historical data only applies for 10 minutes a day.

Set it to eg 24:00:00 to have 10 days of history.

BR ,
Erik