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gert · Member 3 Joined: 02 Jan 2015 Posts: 645

FB "LMQTT_Client" for SIMATIC S7-CPU
https://support.industry.siemens.com/cs/document/109748872/
The “Message Queue Telemetry Transport” is a simple protocol on TCP/IP level. It is suitable for messaging between devices with minimum functionality and for transmission via unreliable networks.
With the function block from the "LMQTT_Client" library, the MQTT protocol is implemented into a SIMATIC S7-1500 and SIMATIC S7-1200.

Lean and fast: MQTT
The “Message Queue Telemetry Transport” is a simply structured binary Publish/ Subscribe protocol on TCP/IP level. It is suitable for messaging between devices with minimum functionality and for transmission via unreliable networks with low bandwith and high latency. With these characteristics, MQTT plays a vital role for the IoT and in M2M communication.

Application-related implementation
The "LMQTT_Client" library provides you with one function block each for the S7-1500 CPU and S7-1200 CPU. The “LMQTT_Client” function block integrates the MQTT client function and allows you to transmit MQTT messages to a broker (publisher role) and to fabricate subscriptions (subscriber role). In this, the communication can be secured via a TLS connection. You can reach the broker with a static ip address or a qualified domain name.

The following picture shows the secure mqtt-messaging with a SIMATIC S7-1500.
MQTT Message Queue Telemetry Transport MQTT Message Queue Telemetry Transport

MQTT Message Queue Telemetry Transport MQTT Message Queue Telemetry Transport

Advantages of MQTT