TrnExportCSV

You might share the exact command you're using for TrnExportCSV().

TrendReader is primarily for examining the internal data in trend files to troubleshoot errors, but it does have export ability. When you open a trend HST file, the Save button appears and will export the info from the HST and all numbered data files to a CSV file. 

There's a related stand-alone tool called Batch TrnExportCSV which is designed to export multiple trends to CSV files so they can more easily be imported back into Citect or another app if desired.

Another option is the TrnExportCSVMulti tool from the Toolbox. It's a Cicode function that extends the functionality of TrnExportCSV and improves performance. Note that TrnExportCSVMulti has been in the toolbox for years, but it seems to have disappeared so I just uploaded it again.

Thank you very much Erik!!! I was able to export the data with  Batch TrnExportCSV. Great tool. I didn't know it.

I don't know what version of TrendReader I have but mine looks like this:

No save button, that's why I was lost.

I'm glad you got it working.

For TrendReader, make sure to open the .HST file as I said. Your screenshot shows you opening the .010 file.

Eric, with Batch TrnExportCSV, is there some way to navigate to the .HST file if it is in a hidden folder (such as the default location  C:\Program Data\AVEVA\...etc) ? 

Choose to show hidden folders in Windows Explorer Options:

That option is already selected

You could always use Windows Explorer to copy the files into a normal folder that the tool can access. It's not a good idea to access files that may be open in the Citect runtime anyway.

That's probably what I will do in this case.  Thanks Eric.