Defining alarms on asset models - Amazon IoT SiteWise
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Defining alarms on asset models

Asset models drive standardization of your industrial data and alarms. You can define alarm definitions on asset models to standardize the alarms for all assets based on an asset model.

You use composite asset models to define alarms on asset models. Composite asset models are asset models that standardize a specific set of properties on another asset model. Composite asset models ensure that certain properties are present on an asset model. Alarms have type, state, and (optional) source properties, so the alarm composite model enforces that these properties exist.

Each composite asset model has a type that defines the properties for that composite model. Alarm composite models define properties for alarm type, alarm state, and (optional) alarm source. When you create an asset from an asset model with composite models, the asset includes the properties from the composite model alongside the properties that you specify in the asset model.

Each property in a composite model must have the name that identifies it for its type of composite model. Composite model properties support properties with complex data types. These properties have the STRUCT data type and a dataTypeSpec trait that specifies the complex data type of the property. Complex data type properties contain JSON data serialized as strings.

Alarm composite models have the following properties. Each property must have the name that identifies it for this type of composite model.

Alarm type

The type of the alarm. Specify one of the following:

  • IOT_EVENTS – An Amazon IoT Events alarm. Amazon IoT SiteWise sends data to Amazon IoT Events to evaluate the state of this alarm. You must specify the alarm source property to define the Amazon IoT Events alarm model for this alarm definition.

  • EXTERNAL – An external alarm. You ingest the state of the alarm as a measurement.

Property name: AWS/ALARM_TYPE

Property type: attribute

Data type: STRING

Alarm state

The time series data for the state of the alarm. This is an object serialized as a string that contains the state and other information about the alarm. For more information, see Alarm state properties.

Property name: AWS/ALARM_STATE

Property type: measurement

Data type: STRUCT

Data structure type: AWS/ALARM_STATE

Alarm source

(Optional) The Amazon Resource Name (ARN) of the resource that evaluates the state of the alarm. For Amazon IoT Events alarms, this is the ARN of the alarm model.

Property name: AWS/ALARM_SOURCE

Property type: attribute

Data type: STRING

Example alarm composite model

The following asset model represents a boiler that has an alarm to monitor its temperature. Amazon IoT SiteWise sends the temperature data to Amazon IoT Events to detect the alarm.

{
  "assetModelName": "Boiler",
  "assetModelDescription": "A boiler that alarms when its temperature exceeds its limit.",
  "assetModelProperties": [
    {
      "name": "Temperature",
      "dataType": "DOUBLE",
      "unit": "Celsius",
      "type": {
        "measurement": {}
      }
    },
    {
      "name": "High Temperature",
      "dataType": "DOUBLE",
      "unit": "Celsius",
      "type": {
        "attribute": {
          "defaultValue": "105.0"
        }
      }
    }
  ],
  "assetModelCompositeModels": [
    {
      "name": "BoilerTemperatureHighAlarm",
      "type": "AWS/ALARM",
      "properties": [
        {
          "name": "AWS/ALARM_TYPE",
          "dataType": "STRING",
          "type": {
            "attribute": {
              "defaultValue": "IOT_EVENTS"
            }
          }
        },
        {
          "name": "AWS/ALARM_STATE",
          "dataType": "STRUCT",
          "dataTypeSpec": "AWS/ALARM_STATE",
          "type": {
            "measurement": {}
          }
        },
        {
          "name": "AWS/ALARM_SOURCE",
          "dataType": "STRING",
          "type": {
            "attribute": {}
          }
        }
      ]
    }
  ]
}
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