"error performing subscript operation" on Perspective view text box bindings

Ignition
,
1

CaptureNullProb2
CaptureNullProb21920×1440 403 KB

CaptureNullProb
CaptureNullProb863×814 69.3 KB

In a Perspective View, many text boxes that all have a tag history binding to OPC tags, I'm getting 'null' displayed rather than valid values, and in the warning for the property, per the attached message it is Error_ExpressionEval("Error performing subscript operation").
I have a good connection to the PLC tags that these bindings are to, and the binding previews show ok, per the attached screen shot as well. Also, I can add a new text box and create the same kind of binding to the same tag(s) and it displays / works OK. So... , what might be going on here with this problem/error on the existing components, am I missing something obvious? Thanks much!

2

I suspect there's more to that binding than you're showing us.
Make that binding window taller and screenshot it again.

3

image
image1016×1043 64.3 KB

There you go, about as tall as I can get, thx.

4

Can you make a table and use that same binding on it, except without the expression ?

5

image
image1384×1035 94.4 KB

Yeah, here it is. I made sure that all details were the same, with historical vs realtime and the same date range. Let me know if that's wasn't what you were looking for. Thanks.

6

I'm... not sure where to look.

The Error_ExpressionEval("Error performing subscript operation error suggests that there's an issue when trying to retrieve data from the dataset with the subscript operator ([0,2]), but... I don't know what that issue would be.

One last shot: Try changing the return format of the query from dataset to document, and in the expression change {value[0,2]} to {value}[0]['durationOff'], see if that also throws an error.

7

  1. When I do your suggestion, changing it to 'Document', changing the format Transform, then I get null value returned, but not null outlined in red as if there is an error.

  2. Interesting find since my last reply when I was trying this! If I remove the tag path, then apply, OK to exit and save the project, and then go back into the binding, re-add the tag by browsing to it again and then apply, OK, exiting and save the project, it fixes it! The correct value then populates without error. I have a LOT of text boxes on the view to do this to, but it would fix it. So.., some kind of bug/corruption perhaps?

Thanks again Pascal for the help.

8

You might have had a similar situation if you did a refreshBinding on the bindings.