MQTT Support in Iot Hub

Question

Hi,

We currently have PLC's with MQTT modules deployed in several locations. The MQTT modules we have chose explicitly only send MQTT messages to and from these PLCs. These messages are super infrequent. We use them for error status and to change a few parameters that determine system performance. This being said we would now like to use Iot Central to display this data use our existing infrastructure. We are pushing data from our current cloud provider to the service and it works as intended. But to keep things simple we would like to move everything to Azure. However, we have run into some issues and would like to know if a solution with Azure's limited MQTT abilities is even possible for what we want. After poking around documentation and the portal for a few weeks we tried two paths, neither gave us the desired result.

1. We are able to directly connect our devices to Iot Central, but we are unable to work with that data in the cloud as Iot Central creates a hub in the background. Is there a way to do this?
2. If we connect our device to the Iot Hub, we could use a data stream to work with the data by storing the data in a blob. However, our data is super infrequent, and streams start at $0.11 an hour so this solution does not make sense as it is significantly more expensive than what we have currently set up on a different cloud provider. Are we forced to use data streams to work with MQTT device in the Iot Hub?

Wondering if there is a solution to either of our paths, or if there is another solution we could not find? If not, is Azure not made for our type of application? Should we continue with our current cloud provider for MQTT processing and continue to push the data to the Iot Central App?

Answer 1

Hi,

In your case (such as the telemetry data are super infrequent), the messages can be routed to the Azure Event Grid service and using an eventing for handling a device telemetry data in the Pub/Sub manner.

Using the Azure IoT Central App, you can pulled up the last value of the telemetry data, send the command, update properties, etc. using the REST APIs, see more details here.
I have still recommending to use the PnP device model created based on your current device infrastructure, when the devices are planned to connect with an IoT Central App. Note, that the Azure IoT Central App is driven by device model.

Thanks
Roman