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MQTT is here to stay. That’s why we built a Sparkplug B MQTT collector for our IIoT platform Factry Historian. Product expert David Dierickx addresses the value it brings to the historian, and what’s in it for your industrial business.
Sparkplug B is an open standard and licence-free messaging system based on the Message Queuing Telemetry Transport protocol (MQTT). It has become extremely popular for IIoT applications, and not without good reason.
The main idea behind MQTT, which was developed as early as 1999, was to create a simple, lightweight and highly reliable communication protocol that could be used for a wide range of use cases in various industries.
Through its open nature, its high reliability and availability, and by requiring minimal resources and network bandwidth, the MQTT protocol is born for industry applications such as real-time process and asset management.
MQTT aimed to implement a publish-subscribe, machine-to-machine network protocol for message queuing. Yet, it left out all specifications around how topics and the payload should be structured and how devices should interact.
Sparkplug B fills this gap by providing a standard and vendor-neutral specification for data formats and state management, and how topologies should be structured within the IIoT architecture. Plain and simple.
As a result, MQTT clients are provided with a framework to seamlessly integrate production data from their applications, sensors, and devices within the MQTT infrastructure, in a bi-directional and interoperable manner.
The OPC-UA standard protocol is mainly used to connect machines, while MQTT is leveraged to connect applications and systems. Each protocol has its own advantages, and each one is better suited for different use cases.
The central concept of OPC UA is a one-to-one topology where clients request data and servers respond with that data. For example: a PLC connected with a SCADA system requests data from sensor values and sends commands from the SCADA to a PLC.
While OPC-UA is a very reliable, open and very feature-rich communication protocol, it does not quite offer the same accessibility and openness as the MQTT protocol.
Using Sparkplug B, a point-to-point IIoT architecture is replaced with a publish & subscribe messaging system, having all connected parties on the same page about how to receive, publish, and interpret the data.
So what’s in it for you?
Using a single technology to rule all systems, combined with heightened visibility and more general expertise that is available for MQTT, will translate into a more sustainable IIoT architecture and therefore also cost savings.
The core benefit of MQTT is that it is extremely lightweight. Packets sent over MQTT are significantly smaller and require less overhead, making this protocol better for networks that are unreliable or have limited bandwidth.
One of the most prominent features of Sparkplug MQTT is that it creates a publish-and-subscribe functionality: a message bus to publish data on different channels, allowing subscribers to receive the data in an easy way.
IT managers will happily embrace the MQTT protocol, as it is very familiar to them and allows the IT department to plug in on it easily, without requiring structural knowledge of the industrial systems behind it.
By using MQTT, plugging into the system and doing custom development becomes a lot easier, and can be done internally by the IT department. As a result, it enables companies to save a huge deal on development costs.
Before MQTT, industrial data could only be made available through protocols such as OPC-DA and Modbus. By enabling our clients to plug in directly into MQTT Sparkplug B, the need for additional software licences is eliminated.
With MQTT, devices aren’t required to be connected point-to-point anymore, e.g. from SCADA to one or more PLCs, but instead uses one central message bus to retrieve and publish data, and exchange commands between them.
MQTT makes the implementation of cyber security measures easier since you can also centralise the security concept. As an additional measure, many companies separate the production networks from the corporate network.
Another benefit of one central message bus over P2P-connections is that it allows for greater visibility. MQTT offers a complete view of the whole set-up without having to consult design schemes, thereby facilitating your workflow.
As a descendant from OPC-DA, OPC-UA has a long history of industrial application. In fact, it was created in 2008 by an industry consortium to boost interoperability between machines of different manufacturers.
OPC-UA will remain the standard for exchanging data between two devices. However, for all the reasons mentioned, chances are that MQTT will outgrow OPC-UA as a communication protocol, especially for larger IIoT set-ups.
In the slipstream of Factry Historian’s v5 update, we are currently adding a series of minor product features, such as this Sparkplug MQTT collector and a new collector failure feature. Both were developed on request by our clients.
Furthermore, we are also planning a few major updates to Factry Historian in the coming year. Along with other exciting stuff, we will be focusing on making our IIoT platform even more useful for various roles in the company.
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