MQTT Transmission supports custom tag properties to enable certain features. Creating custom properties on MQTT tags is a simple process and is no different than custom properties on any other Ignition tag (as documented here).

A refresh of the associated Transmitter will be required after any custom tag property is added, removed or updated

Custom Tag Properties

ExcludeFromPayload

Name: ExcludeFromPayload

Type: Boolean

Action: Controls whether or not a tag is included in Transmission Sparkplug message payloads.

Prior to v4.0.16, UDTs are not supported.

From v4.0.16 onward when applied to a UDT Definition, the UDT definition will not be added to the NBIRTH payload. If a nested UDT definition has the 'ExcludeFromPayload' property is set to 'true', the parent UDT will also be excluded from payload.


StoreAndForward

Name: StoreAndForward

Type: Boolean

Action: Controls whether or not a tag is stored in a configured HistoryStore when Transmission is offline.

This property works together with the Enable History Storage by Default property set in MQTT Transmission under the Settings > Transmitters > History Settings tab. If added to a tag and set to the reverse of the global parameter, it will override the global setting for that specific tag.


TagEventTracer

Name: TagEventTracer

Type: Boolean

Action: Controls whether or not a tag event tracing is generated for this tag.

  • Logs the timestamp (human readable and ms since epoch) and value when the BIRTH is built
  • Logs a timestamp (human readable and ms since epoch) and every time that tag changes and its value
  • Log a timestamp and value when a metric push happens

Available for any tag consumed by MQTT Transmission or Injector Agents

Available in release 4.0.17 or greater

Applying this custom parameter to multiple tags can result in significant system performance issues

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