I have a device which is not capable of Sparkplug, thus I have reverted to using “raw” JSON and a custom namespace in MQTT-Engine, with the JSON Payload flag turned on. This works well enough, except I would like to be able to write metadata to the Ignition tags that get created (i.e. Timestamp, EngUnits, Description, etc). Is this possible using custom namespace? If so, how? I am able to create any JSON layout within the publishing device.
There is no built-in support for this in Custom Namespaces. You could use scripting within Ignition to update Engine tag properties. The values for these properties could even be read from another Custom NS tag so that the property values are still defined at the edge device. Downside would be at least one additional metadata tag per edge tag.
Thanks for that Nathan. I wondered as much, but it was worth asking. I’ll create a script in Ignition to update the properties accordingly.