MQTT

MQTT is a lightweight, publish-subscribe network protocol that transports messages between two devices. All messages between the devices (clients) go trough an MQTT broker (server). The protocol runs over TCP/IP. It is designed for connections with remote locations where a "small code footprint" is required or the network bandwidth is limited.

Engiby has developed an MQTT client library for Saia PCD^® systems that allows you to publish PCD data and subscribe to defined topics. Other MQTT client, who subscribe to a topic in which you publish data will receive what you publish. On the other way, if you subscribe to some topics you will receive data published by other MQTT clients in those topics.

 The Quality of Service 2 has recently been implemented. This is the highest level of service in MQTT. This level guarantees that each message is received only once by the intended recipients.

 The NG-Configurator has been implemented in the MQTT library. This powerful tool allows you to configure publish and subscribe transmissions easily and efficiently in an Excel file. It's even possible to save PCD ressources, which is not possible with the FBoxes. More info here.

 Simple JSON structures can now be build and publish with the library. The JSON structure must be defined in an Excel file and NG-Configurator generates the necessary code to publish it. PCD ressources can be inserted in the JSON structure like registers, flags, and texts. For more complex JSON structures, scripts can be developed on request. More info about NG-Script here.

Restrictions:
The library complies with the MQTT standard 3.1.1. (The standard 5.0 is not supported)
It is not allowed to use wildcards in the topics you subscribe to.
No secure link is supported by the PCD. (Only the username and password is supported)

Please contact Engiby for any request.

• PG5 V 2.3.xxx