Why is MQTT Sparkplug B revolutionizing Industry 4.0?

What is MQTT?

MQTT (Message Queuing Telemetry Transport) is a publish-subscribe messaging protocol based on TCP/IP. Messages are sent by "publishers" on a channel called a "topic". These messages are then read by "subscribers" to that same "topic".

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MQTT is a simple, secure, and extremely lightweight protocol primarily used in IoT projects.

According to measurements conducted on 3G networks, MQTT's throughput is 93 times faster than HTTP's.

However, MQTT was designed to be as open as possible and does not standardize topics or message structures. These shortcomings prevent its widespread adoption in the industrial IT and SCADA world.

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What is MQTT Sparkplug B?

Sparkplug B is a specification that formalizes topic naming, message content, and element states in MQTT-based information systems. It is the technological answer for industrial IT and SCADA, compensating for the lack of structure offered by classic MQTT.

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The Sparkplug specification defines the following three objectives:

1. Topic labels optimized for industrial systems

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2. A messaging mechanism that enables equipment state management

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The "message types" enable real-time synchronization of each element in the MQTT Sparkplug B infrastructure with the supervisory system. When an element is integrated into the infrastructure, it first introduces itself with a “BIRTH” message. Then, upon state changes, “DATA” messages will be sent (or received in the case of commands). Finally, when an element is removed from the system, a "DEATH" message is sent.

With this mechanism, there is only one source of truth: the site!

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3. An optimized message structure for industrial systems

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This message structure allows for the retrieval of key information perfectly suited for the industrial sector, including:

• Timestamp at the data source
• The data type
• ....

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Example

To illustrate the mechanisms explained previously, here is an example of implementing a MQTT Sparkplug B infrastructure in the context of monitoring a water pumping station.

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In this use case, the pumping PLC includes two pumps, each broken down into three pieces of information. The example below shows the content of a MQTT Sparkplug B message published on the DDATA topic in the event of a state change on one of the pumps.

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To illustrate this example, the message content is intentionally decoded. Indeed, MQTT Sparkplug B natively encodes and decodes messages to maintain efficiency and performance between publisher and subscriber.

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How to connect these devices to the SCorp-io solution

Option 1: use the “Connect” module

Standard solution for connecting equipment to the SCorp-io solution using the module Connect. It enables communication between industrial edge devices and the SCorp-io cloud service. The module Connect can be installed on an infrastructure machine. If no infrastructure is available on site, we provide a pre-configured industrial Raspberry Pi-type mini-PC.

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Option 2: Use the MQTT Sparkplug connector integrated into the SCorp-io cloud module

A solution where you use equipment with integrated MQTT Sparkplug B. In this case, the Connect module is no longer necessary. You simply need to activate the MQTT Sparkplug B connector in your cloud project to see your data appear!

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Key takeaways about MQTT Sparkplug B

• ‍Open source
• ‍Lightweight and secure
• ‍Message structure adapted for industry
• ‍Integrated by an increasing number of manufacturers (Wago, Opto22...)

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MQTT Sparkplug B enables automatic synchronization of site data with your SCorp-io supervisory system. The notorious, tedious step of the "interface file" between the PLC and the supervisory system is eliminated. 

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If you're interested in testing SCorp-io, you can sign up here for our Early Adopter program!

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