SYSTEM DESCRIPTION
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8027311 / V1-0/2022-04|SICK
Subject to change without notice
O P E R A T I N G I N S T R U C T I O N S | TDC-E (Telematic Data Collector)
Fig. 7:
MQTT protocol
Legend
A
MQTT client
B
MQTT message broker
C
MQTT client
1
Provides topics (publish)
2
Subscribes to topics (subscribe)
•
MQTT is a client-server protocol that follows the publish/subscribe principle.
•
Clients send messages with a topic to the MQTT message broker after the connection
is established, which classifies the message hierarchically (e.g. “TDC-E temperature
sensor/temperature”).
•
Messages always consist of a topic and the message content.
•
Clients can subscribe to these topics, with the MQTT message broker forwarding the
received messages to the appropriate subscribers.
•
It is the TDC-E that assumes the publisher role within the gateway system.
•
It uses the MQTT protocol to send topics containing sensor data within a defined
structure.
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The client server is the subscriber of this data.
•
Thanks to the defined topic structure, this service is able to retrieve the messages and
continue to process them.
MQTT
