Configure sensors and observe MQTT delivery

Open IoT Operations to follow the sensors, broker and topics in this prepared lab.

Configure a sensor with its broker, topic, interval and signal recipe, then save.

Start a subscriber on the Linux observer to watch the temperature topic.

Use Publish Now to send a unique reading and check its topic and payload.

The observer receives that same reading, and Control C disconnects the subscriber.

Turn Running on for periodic readings, then stop the sensor when you finish.

Publish a retained reading and replace it with the latest value.

A fresh subscriber receives only the latest retained value for its matching topic.

After deleting the retained value, a fresh subscriber waits for the next live message.

This walkthrough uses the in-lab MQTT client with quality of service zero.

Send Sparkplug JSON birth and data messages for this example edge and sensor.

Check the group, device, metric count and sequence in the Sparkplug view.

A death message marks the example device offline.

Stop the broker and confirm that a manual publication fails without increasing its counter.

Restart the broker and make a new explicit publication to verify recovery.

Switch labs and return to confirm that readings and saved settings belong to the correct lab.

This separate example broker already has a user and a restricted topic.

Wrong credentials and a disallowed topic are refused without changing its retained messages.

The allowed publication succeeds, and a correctly authenticated subscriber receives its value.