What is MQTT Sparkplug?

3. Unified Namespace (UNS)

The Unified Namespace (UNS) is a concept in the field of data management that aims to unify different data sources and types under a common namespace. Essentially, UNS provides a unified view of data, regardless of its physical storage or structure. Instead of having separate namespaces for each data source, all data is organized under a single umbrella, making it much easier to manage and access information. By creating a coherent data landscape, UNS enables seamless data integration and improves the transparency and accessibility of information for organizations and applications.

A significant use of UNS can be found in the area of Sparkplug. Sparkplug uses the ideas of the Unified Namespace to provide a standardized method for transferring data between industrial devices and applications. By creating a unified namespace for devices, sensors and controllers, Sparkplug enables smooth integration and interoperability in complex IIoT ecosystems. This not only simplifies the development and implementation of IIoT solutions, but also increases the efficiency and reliability of industrial processes.

4. Sparkplug A vs B

The Sparkplug specification is equipped with two definitions for the MQTT payload. Thus, Sparkplug A and Sparkplug B also result in two versions for industrial use. Sparkplug A is based on the open source definition of the Google Protocol Buffer from Kura. The Google Protocol Buffer is a data format for serialization with an admixture language for interfaces. Sparkplug B has been developed by many system integrators, experts and end users and provides a comprehensive data model for MQTT communication. Sparkplug version B is much more widely used in industry. When Sparkplug is mentioned, it is usually Sparkplug B that is being referred to.

5. Sparkplug in the industry

The Sparkplug specification was developed for industry and easy deployment in the field level (OT). The lightweight communication creates many different application areas. By using Sparkplug nodes, non-Sparkplug capable devices become communication participants in the Sparkplug network. Therefore, the Sparkplug specification can be used in any industry.

Companies with the goal of digitization, for example from the automotive industry, the oil industry or system integrators, rely on the Sparkplug specification. The lightweight and standards-based communication protocol has quickly secured its place since its development.

6. Sparkplug advantages

The Eclipse Foundation created the Sparkplug Working Group because the industry was looking for a complement in MQTT communication. Allowing machines and devices to communicate with MQTT brings numerous benefits. However, manually creating structured MQTT topics and MQTT payloads at the field level (OT) is very cumbersome. Many machines and devices do not provide the ability to add structure to MQTT messages.

Sparkplug already brings the required structure, ensuring little programming effort and easy and fast deployment in practice.

The MQTT topic and the MQTT payload have a fixed standard in the Sparkplug specification that is consistent throughout the communication. Together with the MQTT technology, Sparkplug accelerates and simplifies internal communication.

7. What is Sparkplug needed for?

The defined structures of the Sparkplug specification facilitate and accelerate internal communication. Machines and devices can thus communicate with IT by sending their data to an MQTT broker. Databases, cloud environments or other Sparkplug-enabled systems can then receive this data and use it for further processing. One cloud environment that can already receive data using the Sparkplug structure is the HiveMQ cloud. The co-founder of the Sparkplug Working Group is making MQTT data available via Sparkplug around the world. Being able to access data around the world is just one of the many benefits of digitization. Sparkplug makes it even easier to implement digitization in your own company.

The lightweight and efficient MQTT communication in combination with the Sparkplug specification offers a fast and secure transfer of data from OT to IT.

8. Safety

Since Sparkplug communicates using the MQTT message protocol, it also benefits from MQTT’s high security standards. MQTT builds a TCP/IP transport layer with which no information is sent unencrypted on the network. In addition, SSL/TLS ensures that the connection of all communication participants is encrypted and secured. This encryption prevents third parties from interfering with the network by posing as communication partners. The encryption detects this attempt and protects the internal communication. An authorization framework divides communication participants into a white and black list and additionally increases security with MQTT.

9. Sparkplug in comparison

Sending data via MQTT from the OT to the IT does not only work with Sparkplug. Data can also be shared via MQTT or OPC UA Pub/Sub. The relevant differences to the Sparkplug specification are shown here.

Sparkplug vs MQTT

Communication via MQTT offers the possibility to individually design the MQTT topic and the MQTT payload free of specifications and structures. Machines and devices that cannot be bound to a structure can thus still operate in the MQTT network. A company’s own standard can also be integrated in this way. This standard is specified for machines and devices as well as systems in IT. In this way, it is possible to communicate internally with the company’s own standard.

Sparkplug vs OPC UA Pub/Sub

With OPC UA Pub/Sub, communication is also based on the MQTT principle. With this type of communication, the data is given the OPC UA standard. Machines and devices can share their OPC UA data directly with the network via MQTT. This standard ensures little programming effort and offers fast deployment in practice. Via the MQTT broker, other devices or systems such as ERP or SQL can be connected and integrated into the network.

10. Sparkplug example

Sparkplug-Topic

All MQTT clients that communicate using the Sparkplug B principle use the following MQTT Topic structure:

[namespace]/[group_id]/[message_type]/[edge_node_id]/{[device_id]}

Sparkplug-payload

A Sparkplug payload consists of the following five components.

• Timestamp: The timestamp is represented as a 64-bit integer indicating milliseconds.
• Metrics: Information is passed here that describes, for example, data types present in the message.
• SEQ: The SEQ is the sequence number. All messages in the Sparkplug network are assigned a sequence number and counted in ascending order.
• UUID: UUID is used to represent a message scheme. For example, an encoding mechanism, should the message content be encoded.
• Body: Body is the message content that can be individually felt and used by the user with data.

Sparkplug Payload Example

The Sparkplug payload is sent in binary form, in protobuff format. Although the structure resembles a JSON structure, this is not the JSON format.

{
“timestamp” : 1486144502122,
“metrics” : [ {
“name” : “algorithm”,
“dataType” : “string”,
“value” : “GZIP”
} ] “seq” : 0,
“uuid” : “SPBV1.0_COMPRESSED”,
“body” :
}