Environment Variables Used by the MQTT Collector

The environment variables used by the MQTT collector are available in the historian-mqtt-collector-config.json file. The following table describes these variables.
Parameter Description Default Value Valid Values
DebugMode The debug mode for the MQTT collector. 00
  • 00: Indicates that debugging is disabled.
  • ff: Indicates that debugging is enabled.
HistorianNodeName The host name of the Historian server to which you want to send data using the MQTT collector. A value is required.
InterfaceName The name of the MQTT collector. You must not change this value. EdgeMQTT
DefaultTagPrefix The default prefix for the tags created by the MQTT collector. For example, if you enter mqtt, for a tag named pressure, a tag with the following name is created: mqtt.pressure EdgeMQTT
Hostname The host name of the machine on which you the MQTT broker is running. A value is required.
Topic The topic to which you want the MQTT collector to subscribe. A value is required.

You can subscribe to multiple topics. For example, if you subscribe to Home/#, you will receive messages published to the child topics as well (such as Home/FirstFloor, Home/SecondFloor).

HS_NUMBER_OF_LOG_FILES The maximum number of log files to be created. Once this value exceeds, the oldest file will be deleted to accommodate the new one. 100 1 to 100
HS_SIZE_OF_EACH_LOG_FILE The maximum size of a single log file, in MB. If this value exceeds, a new log file will be created. 10 1 to 10
Note: You cannot define tags in the JSON file. Tags are automatically created based on the data collected by the MQTT collector.