Publisher diagnostic items

The publisher diagnostic items provide diagnostic information specific to the MQTT Publisher.

Publisher Query Items

Query items extract diagnostic data related to the MQTT Publisher based on the edge gateway/device and payload type. The query item syntax for the MQTT Publisher is

• /$SYS$DIAG/<Item Name>?EG&<Payload Type> (at the edge gateway level), or

• /$SYS$DIAG/<Item Name>?D=<Device Name>&<Payload Type> (at the device level)

A default device group <Publisher Node Name>_$DIAG$ has been added in the Publisher to access the diagnostics data of SuiteLink and PCS clients. The query item syntax for SuiteLink and PCS clients is:

• <Publisher node name>_$DIAG$/<Item Name>?EG&<Payload Type> (at the edge gateway level), or

• <Publisher node name>_$DIAG$/<Item Name>D=<Device Name>&<Payload Type> (at the device level)

where,

• <Item Name> is the diagnostic system item. The item name can be one of the following:

  <ItemName>	DataType	Read/ Write	Description
  PublishedItemCount*	Int32	R	Displays the total number of published items under the MQTT broker.
  QoS	String	R	Displays the Quality of Service configured in Publisher Device. [Example = QoS0, QoS1, QoS2]
  RetainLastPublishMessage	Bool	R	Displays 'True' or 'False' based on whether the Retain last message checkbox was selected during the configuration of the MQTT publisher. Value 'True' means that the last published message is kept in the broker.
  PublisherBirthMessageTime	VT_DATE (DateTime)	R	Displays the time when publishing starts. Default value is 01/01/1970 00:00:00 AM and Quality = 0x20.
  PublisherDeathMessageTime	VT_DATE (DateTime)	R	Displays the time when publishing stops. Default value is 01/01/1970 00:00:00 AM & Quality = 0x20.

  * These items can also be accessed at the global level

• EG is the Edge Gateway

• D=<DeviceName> is the name of the specific device under the edge gateway

  Note: D=0 represents the edge gateway

• Payload type is the format of the message payload. The payload type can be one of the following:

  • JSON

  • SP (Sparkplug)

For example, to access the Quality of Service of a publisher device (name: Device_1), the syntax is:

/$SYS$DIAG/QoS?D=Device_1

For a PCS Client to access the Quality of Service of a publisher device (name: Device_1), the syntax is:

pub1_$DIAG$/QoS?D=Device_1 (pub1 is the name of the publisher node)

Note: Diagnostic items for the Publisher (Node Type = MQTTPublisher) under the MQTT Broker are not supported. The node type MQTT_Publisher which is directly under root Configuration node supports diagnostic items.