JSON Derived Tags

[jlandwerlen]

From ICC yesterday, there was a discussion on using JSON derived tags for OPC-UA. Was curious how many actually do this, besides DMC.

[pturmel]

Commonly used with the built-in OPC server of modern Siemens PLCs:

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…