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Workflow 6: Create DeviceHub Device + Tags

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6. Create DeviceHub Device + Tags

UI trigger: DeviceHub -> Add Device -> (configure) -> Add Tag

This is the most common chain customers struggle with. Each sub-step feeds data into the next.

Step table

Step	API Name	Method	Endpoint / GraphQL Operation	Input	Output / What to capture
1	List of Drivers	`POST`	`{{edgeUrl}}/devicehub/v2` -> `ListDrivers`	No input required	`DriverID`, `Name` per protocol (e.g. Modbus TCP, OPC UA, etc.)
2	Get Driver Template by DriverID	`POST`	`{{edgeUrl}}/devicehub/v2` -> `GetDriver`	`{ID: "<DriverID from step 1>"}`	`DeviceProperties` - required fields/tabs for device config
3	Create New Device	`POST`	`{{edgeUrl}}/devicehub/v2` -> `CreateDevice`	Driver ID + device properties from step 2	`DeviceID`
4	Get Driver Supported Registers	`POST`	`{{edgeUrl}}/devicehub/v2` -> `GetDriver` with `SupportedRegisters`	`{ID: "<DriverID>"}`	`SupportedRegisters[].Name`, `ReadOnly`, `RegisterProperties` - valid register types and value types for this driver
5	Create Tag	`POST`	`{{edgeUrl}}/devicehub/v2` -> `CreateRegisters`	`DeviceID` (step 3) + register type (step 4) + tag properties	Tag ID, tag is live

Why step 4 is critical: Each driver supports a different set of register types (e.g. Modbus TCP supports Holding Register, Input Register, Coil, Discrete Input). Calling CreateRegisters with an unsupported type returns a validation error. Always check SupportedRegisters before building the CreateRegisters payload.

Optional pre-validation: Use ValidateUpdateRegisters (GraphQL query) to dry-run a tag payload before actually calling CreateRegisters. The query returns Errors[] without committing anything.