DeviceHub Data Publishing Formats
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DeviceHub collects data from PLCs, applies OMA (Open Mobile Alliance) tagging to classify the data, and it sends data to a message broker for further distribution. Data flows trigger via an API call or execute according to a schedule. OT Link Platform supports multiple data formats.
- DeviceHub Tags generate a Raw Topic, which is a local topic for publishing and subscribing data through the message broker.
- You can configure the DataHub Cloud Connector to connect to Workload Orchestrator using Raw topics.
- You can also use OT Link Platform flows to access data from within OT Link Platform. See, Use OT Link Platform Flows to Visualize Data Flows.
Raw Topic Format
- The raw topic is the local message broker topic. The collected values are the unformatted readings from the PLC register.
- Values are collected from individual registers. OT Link Platform publishes each value to a register-specific topic, in the following topic format: devicehub.raw.{deviceID}.{registerID}
- See DeviceHub Add a Tag.
Example of a Raw Topic
devicehub.raw.F7F72687-2F29-46E7-95E2-B5532471EBAA.2d7473c0-83a0-4174-83cc-b48a63c1b1cf
OMA IPSO (Standard) Topic Format
- If OT Link Platform finds OMA binding/mapping for a collected value, OT Link Platform converts the data into OMA object format and publishes it to the corresponding topic, in the following topic format: devicehub.standard.{deviceID}.{objectID}.{instanceID}.{resourceID}
- See DeviceHub OMA Binding.
Example of an IPSO Topic
devicehub.standard.3200.0.5500
Write Topic Format
- Use OT Link Platform Flows to create a flow that writes data to a register-specific topic, in the following topic format: devicehub.write.{deviceID}.{registerID}
- Each device instance on the devicehub.write.{deviceID}.* topic receives all messages for the corresponding device.
- The device instance executes a write to the specified register on the connected device.
- See Flow to Write to Tags.
Example of a Write Topic
devicehub.write.F7F72687-2F29-46E7-95E2-B5532471EBAA.2d7473c0-83a0-4174-83cc-b48a63c1b1cf
Poll Once Topic Format
- Use OT Link Platform Flows to create a flow that polls a register for data, in the following topic format: devicehub.pollonce.{deviceID}.{registerID}
- See Flow to Poll a Tag Once for an Event-Driven Poll.
Example of a Poll Once Topic
devicehub.pollonce.F7F72687-2F29-46E7-95E2-B5532471EBAA.2d7473c0-83a0-4174-83cc-b48a63c1b1cf