In my application, several tags does not have their updated value displayed in the historical data viewer.
I can see that the tag has a "live" value that is different than the value displayed in the historical data viewer.
There are no deadbands defined for the tags, and the value should be logged in the historical data viewer directly. The minimum log interval for the tags are set to "0"
I am using VTScada light v.12.0.48(32 bit)

As it is now, the historical data viewer is plotting old tag values, not updating to the correct values. The data is basically useless at this point.

This may have to do with the default deadbands and your tag scale range being large. Try defining deadbands and see if that resolves your issue. I believe the default deadbands are 0.1% of the tag scale range. Note that you may need to wait for the value to update to see the new value written.

Yes, you might definitely be correct about this default deadband being the reason for the problem I was experiencing as I see small value changes from a sensor with a large measurement range.
I was searching through the documentation, but did not find any specific details that mentioned the default deadband, which led me to believe this was not a probable cause. I might not have search thoroughly enough if this information is publicly available, if not, it might be an idea to make it publicly available.

Anyways, I solved the problem this time by setting the "minimum log interval" to a fixed value so that the historical data viewer will log the actual tag value at this interval, which is good enough for me in this application.

Thank you for the quick response Dave!

Thanks for letting me know you got this sorted out.

This is probably a great spot to note that the help is contextual so finding the default deadband can be done by clicking into the deadband field and then pressing F1. That should take you here (on your local machine which will contain the help files for your installed version of VTScada):

https://www.vtscada.com/help/Content/D_Tags/D_IOCalc.htm?cshid=23122#LoggingTab

Note that they have the default deadband listed as 0.25% of the scaled range.