Create a sensor with SensorDataUnitType - azure-digital-twins

Question

I'm trying to create a new device with sensor(s).
This is the payload I'm sending to create the new device:
{"Name":"DeviceABC","HardwareId":"D4xxx425","SpaceId":"xxxx-xxx-xx-xx-xxx","Status":"Provisioned","CreateIoTHubDevice":false,"Properties":[{"Name":"VendorName","Value":"MyVendor"},{"Name":"VendorDeviceId","Value":"D4xxx19425"},{"Name":"VendorDeviceType","Value":"electricity"}],"Sensors":[{"pollRate":0,"id":null,"dataType":"Json","dataUnitType":"KilowattHourEnergy","deviceId":null,"portType":null,"port":"electricity","spaceId":null,"type":"Classic"}]}
In this case I want to use a built in type. KWh
{
"id": 186,
"category": "SensorDataUnitType",
"name": "KilowattHourEnergy",
"disabled": false,
"logicalOrder": 0,
"friendlyName": "kWh"
}
The SensorDataType is :
{
"id": 314,
"spaceId": "xxxx-xx-xxx-xx-xxxx",
"category": "SensorDataType",
"name": "Json",
"disabled": false,
"logicalOrder": 0
}
When I do this for other devices without specifying a dataUnitType in the sensor object, it works fine. But as soon as I include it i get this:
{
"error": {
"code": "400.600.000.000",
"message": "Invalid datatype/dataunittype combination used on sensor."
}}

Answer 1

There seems to be a naming convention between SensorDataType and SensorDataUnitType. The convention is that the SensorDataUnitType needs to end with the full SensorDataType. In your example you have:
"dataType":"Json",
"dataUnitType":"KilowattHourEnergy",
But according to the convention it should be
"dataType":"Json",
"dataUnitType":"KilowattHourEnergyJson",
Of course you can't just change KilowattHourEnergy because it's in a system ontology. So to get it working I had to create KilowattHourEnergyJson as a new type.
I guess the most complete answer would include that in your case the SensorDataType probably shouldn't be JSON but should be Energy.