I have this dtdl model I upload to local folder in IoT Plug and Play v0.15.4.0 (prior version behaviour is the same):
{
"@id": "dtmi:com:sergio:devkit;1",
"@type": "Interface",
"@context": [
"dtmi:dtdl:context;2"
],
"displayName": "Machine Part -v1",
"description": "Machine Part data",
"contents": [
{
"@type": "Property",
"name": "telemetryInterval",
"displayName": "telemetryInterval",
"description": "The time interval of this data",
"schema": "double",
"writable": true
},
{
"@type": "Property",
"name": "PartId",
"displayName": "PartId",
"description": "The unique id of the machine part",
"writable": true,
"schema": "string"
},
{
"@type": "Property",
"name": "Alert",
"displayName": "Alert",
"description": "whether or not this machine part needs maintenance",
"writable": true,
"schema": "boolean"
},
{
"@type": "Property",
"name": "ledState",
"displayName": "LED state",
"description": "Returns the current state of the onboard LED.",
"writable": true,
"schema": "boolean"
},
{
"@type": "Telemetry",
"name": "Description",
"schema": "string"
},
{
"@type": "Telemetry",
"name": "Code",
"schema": "integer"
},
{
"@type": "Telemetry",
"name": "Temperature",
"displayName": "Temperature",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "Humidity",
"displayName": "Humidity",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "pressure",
"displayName": "Pressure",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "magnetometerX",
"displayName": "Magnetometer X / mgauss",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "magnetometerY",
"displayName": "Magnetometer Y / mgauss",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "magnetometerZ",
"displayName": "Magnetometer Z / mgauss",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "accelerometerX",
"displayName": "Accelerometer X",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "accelerometerY",
"displayName": "Accelerometer Y",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "accelerometerZ",
"displayName": "Accelerometer Z",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "gyroscopeX",
"displayName": "Gyroscope X",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "gyroscopeY",
"displayName": "Gyroscope Y",
"schema": "double"
},
{
"@type": "Telemetry",
"name": "gyroscopeZ",
"displayName": "Gyroscope Z",
"schema": "double"
}
]
}
My expectation is that because properties ledState and Alert properties are writeable, these should be both reported and desired properties. However the IoT Hub Device in Azure portal (see below) shows them differently and I don't know why. How do I set the properties in the DTDL model I upload to IoT P&P to be reported or desired?
{
"deviceId": "mymxchip",
"etag": "AAAAAAAAAAk=",
"deviceEtag": "NDU1NDk0NDM4",
"status": "enabled",
"statusUpdateTime": "0001-01-01T00:00:00Z",
"connectionState": "Connected",
"lastActivityTime": "2023-01-09T07:26:48.611708Z",
"cloudToDeviceMessageCount": 0,
"authenticationType": "sas",
"x509Thumbprint": {
"primaryThumbprint": null,
"secondaryThumbprint": null
},
"modelId": "dtmi:com:sergio:devkit;1",
"version": 164,
"properties": {
"desired": {
"telemetryInterval": 5,
"Alert": true,
"$metadata": {
"$lastUpdated": "2023-01-08T07:27:01.9659284Z",
"$lastUpdatedVersion": 9,
"telemetryInterval": {
"$lastUpdated": "2023-01-08T06:54:11.9502921Z",
"$lastUpdatedVersion": 8
},
"Alert": {
"$lastUpdated": "2023-01-08T07:27:01.9659284Z",
"$lastUpdatedVersion": 9
}
},
"$version": 9
},
"reported": {
"deviceInformation": {
"__t": "c",
"manufacturer": "MXCHIP",
"model": "AZ3166",
"swVersion": "1.0.0",
"osName": "Azure RTOS",
"processorArchitecture": "Arm Cortex M4",
"processorManufacturer": "STMicroelectronics",
"totalStorage": 1024,
"totalMemory": 128
},
"ledState": false,
"telemetryInterval": {
"ac": 200,
"av": 1,
"value": 5
},
"$metadata": {
"$lastUpdated": "2023-01-09T07:28:26.0068306Z",
"deviceInformation": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z",
"__t": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"manufacturer": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"model": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"swVersion": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"osName": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"processorArchitecture": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"processorManufacturer": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"totalStorage": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
},
"totalMemory": {
"$lastUpdated": "2023-01-09T07:28:25.4599426Z"
}
},
"ledState": {
"$lastUpdated": "2023-01-09T07:28:25.7411971Z"
},
"telemetryInterval": {
"$lastUpdated": "2023-01-09T07:28:26.0068306Z",
"ac": {
"$lastUpdated": "2023-01-09T07:28:26.0068306Z"
},
"av": {
"$lastUpdated": "2023-01-09T07:28:26.0068306Z"
},
"value": {
"$lastUpdated": "2023-01-09T07:28:26.0068306Z"
}
}
},
"$version": 155
}
},
"capabilities": {
"iotEdge": false
}
}
CodePudding user response：
You're correct that a DTDL writable property will appear as both a reported and desired property in the device twin. However, this is dependant and the behavior of the device.
If you set a desired property using a service API, that updates the desired property value in the device twin. The device should then send an Ack when it's received and processed the desired property - in your example above, it looks as if the device has done this for the telemetryInterval property. The device hasn't acknowledged the Alert desired property update.
When the device sends a reported property, the device twin is updated with the value sent by the device. In the example above, the device has sent deviceInformation, ledState, and telemetryInterval reported properties. The telemetryInterval was sent in response to a desired property.
You can find more details here: