Mqtt - Anybus CompactCom 40 Network Manual

MQTT

11 MQTT
MQTT is a publish-subscribe messaging protocol that runs on top of TCP/IP. It was first
developed to transmit data from field devices on remote locations over unreliable satellite links
with limited bandwidth. This initial use case has shaped the protocol to offer a limited number of
features and only adds a small overhead to the data to be transmitted. This resource constrained
protocol has proved useful when pushing data (e.g. diagnostics) from devices to IT systems. The
MQTT message flow is shown in the figure below.
Publisher
Fig. 8
Data is tagged with a topic string. The topic is used by a client, to recognize the messages it is
subscribing to, when they are published by a certain device to the broker.
See also....
• mqtt.org
• Network Configuration Object (04h) (Anybus Module Object)
• MQTT Host Object (E2h) (Host Application Object)
• Application Object (FFh), command Get_Data_Notification (13h) in Anybus CompactCom 40
Software Design Guide
Anybus CompactCom 40 EtherNet/IP IIoT Network Guide
publish(topic, data)
Broker
subscribe(topic)
publish(topic, data)
89 (244)
Subscriber
SCM-1202–069 1.9 en-US