Modify element of tag array from table cell

[simeonw]

I see you have defined the tag data type as a STRING. You might be better to read the tag in as a Document (JSON) data type, as that is how Ignition OPC UA reads in and write to structs.

OPC UA struct data type?

You can take advantage of reading whole structs in OPC UA servers as of Ignition 7.9.12 and 8.0.0. When you bring the tag in you’ll notice Ignition presents a JSON value. The strategy here is a little involved but it works. For each of the UDTs you’ll be subscribing to in the PLC you make a corresponding UDT in Ignition. It should have a “Source” OPC tag member that will correspond to the Node with the struct value in the server and as a result have a JSON value in Ignition. Then for each memb…

You are also attempting to write the data prop directly to the tag. I imagine this would be a dataset, rather than JSON, based on the function you are using to modify the data in run data.

If you look at the QualityCode returned by the system.tag.writeBlocking, you will likely see that it has failed to write to the tag. Try converting your table dataset back to JSON and then writing that to the tag.

As a quick check, you could dump the live tag value in the script console, then also dump the updated value that you are writing back and check whether the structures match.