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 |
|
| 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). |
historian_data | |
| 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.