© Softing Industrial Automation GmbH
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Chapter 4 - IT Settings
4.3.5 MQTT Last Will Settings
When establishing a connection, MQTT Clients, e.g. the dataFEED Gateway MQTT Publisher module, can transfer
an MQTT Topic name and a message to the MQTT Broker. If the MQTT Broker detects that the connection to the
client does not exist any longer (e.g. because a network switch has failed) the MQTT Broker publishes this
message within the topic.
The
MQTT Last Will Settings
view allows to define the
Last Will and Testament
settings for the MQTT connection:
Topic name
The topic name field includes the complete name of the Last Will topic including all hierarchy levels. The
individual hierarchy levels have to be separated by the
/
character.
Testament
The testament field defines the message to be published by the MQTT Broker as testament.
Enable MQTT Retain
By setting the Retain flag the MQTT Broker is instructed to save the most recent data value for the topic.
Depending on the configuration the broker saves the data into the RAM or persistently into the file system/
data base.
Data values without Retain flag are only transferred from the MQTT Broker to those MQTT Subscribers that
are registered at the broker and have subscribed to the appropriate topic in the moment when sending the
data to the broker.
Enable Last Will Option
This check box allows to specify whether the
Last Will and Testament
MQTT connection options are used or
not.
If they are used, additional configuration fields are available.
Saving and applying settings
1.
Click the
Save
button to save your settings.
A hint will appear reminding you that the application of some other settings is pending:
2.
Click at this link. Your settings will be applied.
Depending on the number of modified settings this process may take some time before being completed.
3.
A message in the upper window part will inform you about the successful modification(s).
4.3.6 MQTT Cloud Sample Configurations
The given websites provide examples how to configure the dataFEED Gateway to use it with the MQTT Broker of
a specific cloud provider.
IBM Watson / Bluemix
Link:
https://developer.ibm.com/recipes/tutorials/send-plc-data-via-softing-datafeed-edgate-or-uagate-
Microsoft Azure IoT-Hub
Link:
https://github.com/SoftingIndustrial/azure-iot-device-ecosystem/blob/master/get_started/
