You are currently viewing Conectividad en la Industria 4.0: conociendo los protocolos OPC UA y MQTT

The interconnectivity between systems and machines has reached practically all sectors of the world economy, improving data collection and facilitating integration between different systems. The popularization of concepts related to Industry 4.0. it allowed a transformation of business and processes in companies of the most varied segments.

In another text in the series of articles on communication protocols, we present the history and characteristics of two of the most used models in Industry 4.0 applications: OPC UA and MQTT.

The history of OPC UA

In order to develop a standard communication protocol that would replace previous models and communicate with all of them, companies in the technology segment came together and developed the OPC standard, in 1995. Acronym for "Open Platform Communications", the model allows access to data in real time through the Windows operating system. The first version of this protocol was called OPC Classic and had three standards:

* OPC DA (Data Access): defined the exchange of data, including values, time and quality information.

* OPC A&E (Alarms and events): Responsible for the exchange of information on event and alarm type messages, as well as variable status and status management.

* OPC HDA (Historical Data Access): featured query and analysis methods that could be applied to historical data.

However, even with the creation of the OPC protocol, the problems were not resolved. Although the model offers interconnectivity between devices and has been accepted by the market, it remained restricted to Windows. Thus, it could not be used in other operating systems, such as Linux and Mac (Apple), not even in operating systems that run on industrial controllers, in addition to having very simple security. With that in mind, the OPC UA was developed.

Launched in 2008, the Unified OPC Architecture ensured the connection between the various devices in the plant. The protocol, which is increasingly being implemented in industries, offers platform independent communication, data security, standardization and decentralized intelligence.

Being platform independent, OPC UA implements its own layer of security, based on a public key infrastructure (PKI) that uses an industry standard of x.509 digital certificates and address authentication, authorization, encryption and data integrity. It also has certain additional features like redundancy and connection monitoring, quick and easy installation, and cross-platform deployment.

Knowing MQTT

MQTT, short for "Message Queue Telemetry Transport", is one of the most widely used communication protocols in IoT applications today. Developed in the late 1990s by IBM, the model, which is based on the TCP / IP standard, supports asynchronous communication between the parties, that is, it separates the sender ("editor") and the receiver of the message (" subscriber '), both in space and time. As such, it is scalable in network environments that are not reliable.

The protocol emerged as an alternative for linking sensors in pipelines to satellites and officially became an open standard from OASIS in 2014, when it began to support the most popular programming languages.

With a light and flexible structure, MQTT has become one of the most recognized protocols when developing applications with a high degree of connection. It can be used on very restricted device hardware or on networks with limited bandwidth and high latency. It also supports different application scenarios for IoT devices and services.

Regarding its communication, MQTT defines two contacts on the network: a message broker, which is nothing more than a server that receives messages from clients and routes them to the relevant destination, and innumerable clients, which can be anything that interacts with the broker and signs these messages. That is, the client connects to the broker and publishes the "subject" and message. The broker then sends the messages to other customers who subscribed to that topic. MQTT also uses TLS cybersecurity technology for secure communications through encrypted keys.

Source: BLOG Altus.