Reference tags: binding source to an expression

Is it possible to bind the source of a reference tag to an expression? Or alternatively and less preferably, use scripting to change the source? (the reason this is less preferable is as this is script-based and thus user action triggered, whereas bindings are driven automatically by changes in tags, thus being more robust). I would want to bind this expression to a combination of a string tag value and fixed static text e.g.
source = {[.]Connected PLC} + '/Sensor N'

I have a project where there are a number of PLCs with identical code, and many more plants with 3 sensors that can be hooked up to one of these PLCs. Not all plants can be connected at once due to the limited number of PLCs.

So, I would like to make use of the new reference tags for this if possible, so that I can create my x PLC UDT instances each with my 3 sensor OPC tags. Then I can create instances for each of the plants that have reference tags within them. By default, these would not be set (or set to some default, memory tags for example). When they move a PLC to a plant, then in Ignition they would select from a list of PLCs and then that plant’s reference tags would then point to that PLC instances tags.

Or am I going about this the wrong way? I need to be able to historise all plant values whenever they’re connected to a PLC, so history should be done on each plant’s tags, not the PLC tags.

While waiting, I’m trying to use the new system.tag.configure function to edit this tag.

This is what I get from copying the tag from the tag browser, there’s no mention at all of the ‘Source Tag Path’ property? What’s in the clipboard and what’s pasted in ASCII seems to be different… Exporting the tag shows me the source property which is ‘sourceTagPath’.

  "payload": {"tags": [{
    "attributes": [],
    "dataType": "Float8",
    "displayFormat": "#,##0.##",
    "hasChildren": false,
    "objectType": "AtomicTag",
    "subType": "reference",
    "tagPath": "[default]Plant Equipment/WTG-047/Sensor N"
  "type": "tags"

I have the following code semi-working, but it’s setting the tag type to a Memory tag rather than a Reference tag, despite setting it to reference? Also, how can I get the dictionary definition of the tag via script? As I can’t simple set the ‘sourceTagPath’ property alone, otherwise all the other properties are lost.

newPLC = "[default]PLCs/PLC-B/Sensor N"
tags = { 'name': 'Sensor N',
		 'objectType' : 'AtomicTag',
		 'subType': 'reference',
		 'dataType' : "Float8",
		 'sourceTagPath' : newPLC,
		 'attributes' : []
ret = system.tag.configure(basePath="[default]Plant Equipment/WTG-047",
 tags = tags