SPC Chart and Tag Name starting with a Number

[Former Member]

On a 11.5.3 (latest build) install, we've found that SPC Charts don't like tag names that start with numeric characters. The data points just don't plot. I can right click and get the data, but there are no points on the chart. All other applets work fine with the same tags. Has anyone else seen this?

[Former Member]

If you manually append an underscore to the tagname when assigning it to one of the SPC fields, it should work.

[Former Member]

Hey Rick,

We did try that and it worked. Also when creating the tags in the UDS Admin, I don't believe the UDS Admin will allow for this scenario (along with funky characters like pipes "|"). However, we are using an alias file (export from Historian into Excel, into SQL, and tweaked via Xacute) where the UDS Admin rules aren't enforced, which might be the inherent problem here.

I just thought that if the applets allowed it, the iSPCChart should also.

Thanks.

Edited by: Ryan Miller on Feb 19, 2008 10:04 AM

I'll leave this thread unanswered for a bit to see if anyone else cares to comment.

[Former Member]

Come on, you shouldn't have tags that start with numbers ! Most SCADA's won't even allow this. But historians (for good or bad) tend to be more forgiving with what characters they allow you to use.

I've had a similar problem before, or worse yet, I had a customer that ran a TAGLIST query in xMII, selected and copied the output of that query into excel, then imported it into historian. Guess what? All the tag names imported into the historian had "&nbsp" on the end of them (from copying the HTML into excel) Their historian accepted the change, however xMII didn't like the tag names anymore, and the historian would not let them delete, or modify those tags anymore. THAT was fun to fix!

[Former Member]

Oh, I absolutely agree! But, the tags are controlled not by us, or even the internal group that is working with us. We've made many recommendations on the set up of Historian tags, collection, and compression.

[Former Member]

Oh I definatly know your pains. If I remember correctly (I haven't worked with tag based data in a while) but when we did have tag names that started with a number, xMII would append an underscore "_" to the beginning of the tag name automatically.

[agentry_src]

Hi Ryan,

I have also dealt with this issue on IP21. Since there were literally thousands of tags starting with numbers, we had little choice in using them. But what we did was build a little transaction that took the raw data and built an output document with two columns, DateTime and Value (can have more if you need Tagname, etc.). First thing done was a little xPath to determine the actual name of the data column and assign it to a local property.

Transaction.InputTagData{name(/Rowsets/Rowset/Row/*[2])}

This will return the name of the column of data regardless of whether there is an underscore in front or not. Then use that local property to reference the field instead of the tagname.

Hope this helps,

Mike