topic Re: Read Tag History (SystemLink API) Gives error -251047 in G Web Development Software

Read Tag History (SystemLink API) Gives error -251047

RagMan — Fri, 13 Dec 2024 17:04:02 GMT

I am using the Read Tag History in the SystemLink Tags palatte. The purpose is the provide some history data to a chart on my WebVI.

But I am getting error -251047: The version of the 'nitaghistorian' web service installed on the configured web server does not support workspaces.

I also get the same error in LabVIEW.

I installed G-Web and SystemLink just 3 months ago, so I think the versions are reasonably new. G-Web is 2022 Q3.

Any tips on how to fix this error?

Thanks!

Re: Read Tag History (SystemLink API) Gives error -251047

RagMan — Mon, 16 Dec 2024 18:04:06 GMT

I was able to get it to work by installing the full version of SystemLink. There is a service called "NI System Link Tag Historian service" that is needed for reading Tag History values.

Currently evaluating this. Overall it works ok, but only after I setup the "Configure Retention" and "Configure Tag History Window" appropriately.

Still getting one very old value that seems to be mixed with recent values. In this screenshot below, the last 10 historical values are shown with latest value first. The first element in the "Data" is a data counter. So 133 is the latest value, 132 is the one before that and so on. Somehow the Data with the data counter 27 is persistent and appears even after it should have long disappeared.

Re: Read Tag History (SystemLink API) Gives error -251047

RagMan — Mon, 16 Dec 2024 20:51:12 GMT

I found the reason for the incongruous data #27 ! Turns out it was my mistake. I realized that I was running a another program on a different PC sending data to the same Tag, in this case it was repeating data #27 (real data that was happened to not be changing for a while). So this caused it to appear in the history which I mistook for old data.