IIoT (Industrial Internet of Things) is becoming more mainstream, leading to more vendors implementing innovative monitoring capabilities in the new generation of sensors. These sensors are now multifunctional and provide a host of additional features such as self-monitoring.
With these intelligent sensors, it is possible to set up a system that enables continuous monitoring of the machines and production line. However, the essential requirement to use the provided data for analysis and condition monitoring for preventative and predictive maintenance is to get it from the shop floor to the MES, ERP, or other analysis software suites.
There are a variety of ways this can be done. In this post we will look at a few popular ways and methods to do so.
This has certain disadvantages like actively polling for the data, making it unsuitable for a spotty network, and having high packet loss.
MQTT(Message Queuing Telemetry Transport) eliminates the above problem. It’s very low bandwidth and works excellent on unreliable networks as it works on a publish/subscribe model. This allows the receiver to passively listen for the data from the broker. The broker only notifies when there is a change and can be configured to have a Quality of Service(QoS) to resend data if one of them loses connection. This has been used in the IoT world for a long time has become a standard for data transport, so most of software suits have this feature inbuilt.
The third option is to use OPCUA, which is the standard for M2M communication. OPCUA provides additional functionality over MQTT as it was developed with machine communication in mind. Notably, inbuilt encryption allows for secure and authenticated communication.
In summary, below is a comparison of these protocols.
A more detailed explanation can be found for these standards :
REST API : https://www.redhat.com/en/topics/api/what-is-a-rest-api
MQTT : https://mqtt.org/
OPCUA : https://opcfoundation.org/about/opc-technologies/opc-ua/