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gwhite-211-Visitor
1-Visitor
August 21, 2016
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ThingWorx MQTT Extension and DataChanged Events

  • August 21, 2016
  • 1 reply
  • 2065 views

I'm working with the ThingWorx MQTT extension on version 7.2, and I'm finding that updates to properties via MQTT topics aren't firing DataChanged events on my Things. Manual changes to the properties the topics are bound to fire the DataChanged events. For example, if I use the String type of the data coming from MQTT, I can alter the value and see a subscription on the object change. But if that same change happens via the MQTT topic, no event is fired, even though the property data is updated.

Is there a way to see catch property changes when MQTT topics update a property?

Thanks,

G

Best answer by gwhite-21

I dug into this a bit more and figured out the issue. The DataChanged event was firing on the property being updated via MQTT topic. However, the System user was then trying to update another property on the same Thing, but didn't have permissions to write to that property (the default). I solved this by adding property write permissions for the System user account on the Thing Template runtime instances. After that, the updates worked as expected.

1 reply

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gwhite-211-VisitorAuthorAnswer
1-Visitor
August 22, 2016

I dug into this a bit more and figured out the issue. The DataChanged event was firing on the property being updated via MQTT topic. However, the System user was then trying to update another property on the same Thing, but didn't have permissions to write to that property (the default). I solved this by adding property write permissions for the System user account on the Thing Template runtime instances. After that, the updates worked as expected.

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