Improve communications efficiency and reduce reliance on IT.

Included with Ignition Edge in groov EPIC is an MQTT Transmission module. MQTT (Message Queue Telemetry Transport) is a publish-subscribe (pub-sub) protocol that’s suited to many IIoT applications because of its architecture.

In a pub-sub architecture, a central source, called a broker, handles all data. MQTT clients can publish data to the broker or subscribe to get data from it (or both). Clients who publish data send it only when the data changes (report by exception). Clients who subscribe to data automatically receive it from the broker only when it changes.

Contrast this with a request-response architecture. There the client and server must be connected, because the client requests data directly from the server. The client doesn’t know when the data changes, so it must request it at regular intervals.

MQTT pub-sub offers three main advantages over request-response for IIoT applications:
  • Network traffic is reduced overall, because data is published and sent only when it changes, rather than at regular intervals.
  • Because the broker is a central source for data, servers don’t have to strain to serve multiple clients. And even remote devices with irregular connections or low bandwidth can publish or subscribe to data.
  • For data publishers, there’s another important advantage: data is published using an outbound connection. Most firewalls block inbound traffic (for example, an external client requesting data from an internal server), but they allow outbound connections.

What does an outbound connection mean? It means that the device initiates the connection. Once initiated, data can travel in both directions. For example, whether a groov EPIC is publishing or subscribing to data, the EPIC initiates the connection. That's an outbound connection, which the firewall would allow. Once the connection is made, data can travel bidirectionally. 

A groov EPIC Architecture Example using MQTT


MQTT Transmission with either a Strings payload or Sparkplug-B payload, available through both groov EPIC and the groov Edge Appliance, offers advantages for both on-premises and remote data communication.

groov EPIC systems in industrial areas connect to sensors and actuators through their own I/O and through other PACs, PLCs, and RTUs, and publish and subscribe to data through the MQTT broker.

At the main site, Ignition Edge and the groov Edge Appliance also publish and subscribe data through the broker, while providing database connectivity and system visualization.

MQTT Advantages

  • Designed for industrial systems
  • Device-originating communications
  • Centralized security management at broker
  • Data reported by exception. on change only
  • Lightweight data communications
  • Fewer communication links
  • Much less traffic on network
  • Ideal for intermittent connections
  • Broker can be located onsite or offsite
  • No need for VPNs or open firewall ports
  • Less reliance on IT departments

Additional Resources for MQTT

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