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Topics

Topics in the Databus are the communication channels with other apps. You can create topics with any topic name and assign them to already existing users in the Databus. The topic name is the unique part in the Databus that enables the app to segregate their data points. Users with the right permissions can read data from the assigned topics or publish and subscribe to these topics. Topics do not need a special structure, except for the SIMATIC S7 Connector. If certain apps require specific topic formats, such as the SIMATIC S7 Connector, the topic format must be described in the respective app documentation and applied in the Databus so that the app can communicate with the Databus.

Note:
If you use “/#” at the end of a topic name, you subscribe to all subtopics of the specific topic.

Users and Access Rights to Topics

When creating a user in the Databus, you define the username and password for the user and assign or add topics to the user. When assigning or adding a topic to a user, you define the topic name, if it is a new topic, and the permissions the user have related to this topic. Following permissions are available:

  • No Permission: The user has no access rights
  • Subscribe Only: The user can only read data from the topic and use it for other apps
  • Publish and Subscribe: The user can send data to the topic and use the data for further applications

Receiving Data from SIMATIC S7 PLCs

To receive data from PLCs configured in the SIMATIC S7 Connector, the Databus needs a specific topic format. You find the topic format in the topics section of the SIMATIC S7 Connector.