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MQTT is a machine-to-machine (M2M) / 'Internet of Things' connectivity protocol that is economical with the available bandwidth allowing for communications to be made in more remote locations.

Unitronics' UniStream range of PLCs can now be set up as an MQTT Publisher or Subscriber meaning it can send and receive information over the exciting new protocol using less bandwidth than many other communication protocols.
Fully integrated with SCADA and SQL this Industry 4.0 addition will help your PLC stay connected in the most remote locations.

What is MQTT?

MQTT stands for Message Queuing Telemetry Transport.
It is a publish/subscribe, extremely simple and lightweight messaging protocol, designed for constrained devices and low-bandwidth, high-latency or unreliable networks. The design principles are to minimise network bandwidth and device resource requirements whilst also attempting to ensure reliability and some degree of assurance of delivery. These principles also turn out to make the protocol ideal of the emerging “machine-to-machine” (M2M) or “Internet of Things” world of connected devices, and for mobile applications where bandwidth and battery power are at a premium.

Who invented MQTT?

MQTT was invented by Dr Andy Stanford-Clark of IBM, and Arlen Nipper of Arcom (now Eurotech), in 1999.

Is MQTT a standard?

As of March 2013, MQTT is in the process of undergoing standardisation at OASIS. The protocol specification has been openly published with a royalty-free license for many years, and companies such as Eurotech (formerly known as Arcom) have implemented the protocol in their products. In November 2011 IBM and Eurotech announced their joint participation in the Eclipse M2M Industry Working Group and donation of MQTT code to the proposed Eclipse Paho project.

How does MQTT relate to SCADA protocol and MQIsdp?

The “SCADA protocol” and the “MQ Integrator SCADA Device Protocol” (MQIsdp) are both old names for what is now known as the MQ Telemetry Transport (MQTT). The protocol has also been known as “WebSphere MQTT” (WMQTT), though that name is also no longer used.

Are there standard ports for MQTT to use?

Yes. TCP/IP port 1883 is reserved with IANA for use with MQTT. TCP/IP port 8883 is also registered, for using MQTT over SSL.

Want to know how to use MQTT with your UniStream PLC?

Get in touch with us and we will be happy to help you with your project, to get started you can download this demo application for a simple MQTT setup HERE

This below image helps explain the Publisher, Broker & Subscriber relationship in MQTT

MQTT explained

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