Broker
An MQTT broker is required to exchange or synchronize process data and messages with a smart device.
 | The MQTT broker must be accessible via the IP address or host name from the TwinCAT PLC and the mobile device. TwinCAT and smartphone do not have to be connected directly. |
MQTT is a publisher/subscriber-based communication protocol, which enables message-based transfer between applications. The message broker is a central component of this transfer type, which distributes messages between the individual applications or the sender and receiver of a message. The message broker decouples the sender and receiver, so that it is not necessary for the sender and receiver to know their respective address information. During sending and receiving all communication devices contact the message broker, which handles the distribution of the messages.
MQTT broker requirements for TC3 IoT Communicator
For optimal use of the TwinCAT IoT Communicator app, the MQTT broker should meet the following requirements:
- MQTT protocol version 3.1.1 (see OASIS standard specification)
- Clients require access to the topic (see Topic structure)
- Retain messages and Quality of Service 0 & 1 (see Quality of Service)