MQTT is a publish-subscribe messaging protocol that enables efficient communication between devices over constrained networks. It was developed in the late 1990s by Dr. Andy Stanford-Clark of IBM and Arlen Nipper of Cirrus Link Solutions. Originally designed for remote monitoring and control of oil pipelines, MQTT has evolved into a versatile protocol suitable for a wide range of IoT applications.
In industrial systems, MQTT publishers and subscribers play crucial roles in facilitating communication and data exchange between devices. Let’s explore their functions and how they are used in such systems:
MQTT publishers are devices or applications responsible for generating and sending messages to specific topics on an MQTT broker. In industrial systems, publishers can be sensors, actuators, control systems, or any device that needs to share data with other devices in the network. The MQTT publisher’s workflow typically involves the following steps:
1. Data Generation: Publishers collect data from sensors, process it, or generate it based on the system’s requirements. This data could include temperature readings, pressure values, machine status, or any other relevant information.
2. Topic Selection: Publishers choose an appropriate topic under which to publish their data. Topics serve as a logical channel or label that helps categorize and organize messages within the MQTT broker. For example, a temperature sensor might publish data under the topic “sensors/temperature”.
3. Publishing Messages: Once the data is generated and the topic is selected, the publisher uses the MQTT client library to establish a connection with the MQTT broker and publish the message containing the data to the chosen topic. The MQTT broker then ensures the message is delivered to all interested subscribers.
MQTT subscribers, on the other hand, receive and process messages published to specific topics of interest. Subscribers express their interest in particular topics and receive relevant messages when they become available. In industrial systems, subscribers can be monitoring systems, control systems, dashboards, or any application that needs access to real-time data. The…