Ignition Document tag data type in Sparkplug


We are trying to build a solid application that uses the Sparkplug B library to send data to Ignition (MQTT Engine).
We know of the default SpB aliases:

And these all seem to work sending it to Ignition.
We also want to send tags of type ‘Document’ to Ignition. We saw MQTT Transmission is able to do that, but we don’t know what alias Ignition Engine is expecting for the Document type.

We saw the Ignition tag data types here:

But these aliases seem different then the SpB aliases.
What would the Document type alias be?

Document types are not native to Sparkplug even in the current development branch of the Sparkplug Specification. At Cirrus Link we modified our MQTT Transmission and Engine module to support this datatype outside of the Sparkplug spec. Basically we set the MetaData Content Type to JSON. This is how we do it in Java:


That will tell MQTT Engine to set the Document datatype instead of a String.

I should note that because this is outside of the Sparkplug Spec it is subject to change. But, I highly doubt that will happen in the case of MQTT Engine.


Oh, ok. Thanks for your reply!