Best practice for handling large-scale OPC UA Structured DataTypes / ExtensionObjects

Ignition
,
1

Hi all,

We have a shopfloor where most machine data is exposed via OPC UA Structured DataTypes / ExtensionObjects instead of simple atomic tags. This is based on a standard machine information model, so values and metadata like unit, limits, ID, timestamp, status, etc. come together as one structured object.

The overall scale is large around 100k shopfloor tags/signals follow this pattern.

I understand Ignition can connect and read these, but practically they seem to come in as Document/JSON rather than fully expanded member tags.

I wanted to ask what is the best and most scalable way to handle this in Ignition.

  • Should we keep the structured object as the source and only extract required members into derived tags?

  • Should we flatten things upstream before Ignition?

  • Is there a recommended UDT-based abstraction approach in Ignition for this?

  • What are the real performance concerns at this scale for subscriptions, tag count, memory, historian, alarming, and UI bindings?

  • Any known limitations with custom structured datatypes / ExtensionObjects / datatype definitions in current Ignition versions?

Mainly looking for best practice from people who have implemented this in production, especially at large scale.

2

Some key information that will inform whatever decision you make is:

  • does the server also expose the structure members as their own variable nodes in the address space?
  • is this a "real" server that could handle the load of 100k monitored items, or an embedded server on a PLC where it's crucial you only create monitored items for the structure value nodes?
2 Likes
3

Hi Kevin ,

does the server also expose the structure members as their own variable nodes in the address space? - Yes this tags will be exposed to MES via Ignition OPC UA server
is this a "real" server that could handle the load of 100k monitored items, or an embedded server on a PLC where it's crucial you only create monitored items for the structure value nodes? - Not one single server but combination of 4 gateways with EAM

Thanks