Sparkplug NCMD or DCMD workflow using MQTT Modules

This is the Sparkplug command workflow when using MQTT Engine and MQTT Transmission:

• On a Sparkplug edge client (MQTT Transmission) connection subscriptions are made for
  • spBv1.0/GroupId/NCMD/EdgeNodeId
  • spBv1.0/GroupId/DCMD/EdgeNodeId/#
    
    
• A write to an Engine tag generates a CMD message (either DCMD or NCMD depending on the Ignition folder tag hierarchy) encapsulating the tag write
  • Block Node commands and/or Block Device Commands must be disabled in the MQTT Engine configuration
    
    
• The CMD message is published to the appropriate Sparkplug edge client
  
  
• The Sparkplug edge client (MQTT Transmission) receives the CMD message and decodes the payload
  
  • Block Commands must be disabled the MQTT Transmission transmitter configuration
    
    
• MQTT Transmission writes the tag on the Ignition edge gateway which results in two actions:
  • A write to the associated PLC via the Ignition OPC-US Server and associated driver if the tag is an OPC tag
  • Publish of a Sparkplug DATA message with the appropriate metric name, value, etc. 

• MQTT Engine decodes the published Sparkplug DATA message and updates the appropriate tag under the MQTT Engine tag provider