Models and Asset Modeling¶

In EnOS, modeling is a critical step in abstracting assets into digital objects. Models bridge the physical world and the digital platform by defining the characteristics and behaviors of assets, enabling data management and business applications. Depending on business requirements, assets can be abstracted as either device assets or logical assets. This document provides a detailed explanation of their design and implementation.

Note

When you create models in EnOS Model Management , only models with Model Usage set to Device Connection can be used in EnOS Device Connectivity and Management, and can be queried and updated via the Model Service APIs.

Designing Models¶

Models reflect the characteristics and functionalities of physical assets through attributes, measurement points, and commands:

Model Element	Definition	Real-World Mapping	Examples
Attributes	Static information about an asset that rarely changes during operation.	Basic information or fixed parameters of a physical asset, typically determined by the manufacturer or during installation.	Model No., installation location, rated power
Measurement Points	Dynamic time-series data generated during asset operation, used for monitoring and analysis.	Operational status or environmental data of a physical asset, typically collected by sensors.	Wind speed, temperature, current
Commands	Control instructions or operations an asset can respond to, ranging from simple actions to complex logic sequences.	Executable functions or behaviors of a physical asset, typically associated with actuators.	Start motor, shut down device

Abstracting Assets¶

Assets are classified into device assets and logical assets based on whether they correspond to a physical device. The table below compares their differences:

Dimension	Device Asset	Logical Asset
Real-World Object	Physical device	Business entity or aggregated object
Data Source	Directly from device sensors	Aggregated or computed data
Model Source	Device model, based on hardware characteristics	Business model, based on business requirements

For example, consider a wind turbine. From an external perspective, it appears as a single unit, but internally, it comprises multiple devices. On an IoT platform, you can choose to abstract the wind turbine as either a device asset or a logical asset based on your business needs.

Device Assets and Device Models¶

Defining a wind turbine as a standalone device means it is treated as a single device instance bound to a model. Data from internal components (e.g., generator, blades, sensors) is represented as attributes, measurement points, or commands of that device.

In this scenario, you only need to prepare one wind turbine model. An example is provided below:

Attributes	Measurement Points	Commands
Turbine ID Location Installation Date Generator Model Blade Count Sensor Type	Generator Temperature Generator Speed Generator Power Blade Vibration Frequency Blade Angle Wind Speed Ambient Temperature Wind Direction	Start/Stop Generator Reset Generator Adjust Blade Angle Lock Blades Calibrate Sensor Restart Sensor

Logical Assets and Business Models¶

Defining a wind turbine as a combination of devices means it is treated as a logical asset bound to a business model. Its internal components (e.g., generator, blades, sensors) are treated as independent devices, each bound to its own device model. These models define their respective attributes, measurement points, and commands, with mapping relationships established between the wind turbine model and the device models.

In this scenario, the wind turbine corresponds to one business model, while its internal components (e.g., generator, blades, sensors) each correspond to a device model. This requires designing 4 models and defining the mapping relationships between them.

1. Designing Business Models¶

The business model defines the global characteristics of the wind turbine. Below is an example of a wind turbine business model:

Attributes	Measurement Points	Commands
Turbine ID Location Installation Date	Site-Wide Power Output Site-Wide Wind Speed Site-Wide Vibration Frequency	Start All Devices Stop All Devices Reset All Devices

2. Designing Device Models¶

Each sub-device has its own model, defining its attributes, measurement points, and commands. These sub-device models can be aggregated into the wind turbine either by Referencing Components or by Creating an Asset Tree and Node, which builds a topology while preserving device independence.

Below are examples of three device models:

Device Model	Attributes	Measurement Points	Commands
Generator	Generator Model Rated Power	Generator Temperature Generator Speed Generator Power	Start Generator Stop Generator Reset Generator
Blade	Blade Count Blade Material	Blade Vibration Frequency Blade Angle	Adjust Blade Angle Lock Blades
Sensor	Sensor Type Installation Location	Wind Speed Ambient Temperature Wind Direction	Calibrate Sensor Restart Sensor

3. Configuring Mapping Rules¶

To enable the aggregation functionality of logical assets, mapping rules are required to associate device model with the wind turbine model. Whether you treat the 3 device types as components or child nodes in an asset tree, you can Configuring Property Rules for attributes and measurement points in the wind turbine model. Below is an example of mapping relationships between the wind turbine model and the 3 device models:

Wind Turbine Model Property	Device Model Property	Mapping Rule
Attribute: Turbine ID	N/A	N/A, inherent to logical asset
Attribute: Location	N/A	N/A, inherent to logical asset
Attribute: Installation Date	N/A	N/A, inherent to logical asset
Attribute: Generator Model	Generator Attribute: Generator Model	Turbine.GeneratorModel = Generator.Model
Attribute: Blade Count	Blades Attribute: Blade Count	Turbine.BladeCount = Blades.Count
Attribute: Sensor Type	Sensor Attribute: Sensor Type	Turbine.SensorType = Sensor.Type
Measurement Point: Site-Wide Power Output	Generator Measurement Point: Generator Power	Turbine.SiteWidePower = SUM(Generator1.Power, Generator2.Power, …, GeneratorN.Power)
Measurement Point: Site-Wide Wind Speed	Sensor Measurement Point: Wind Speed	Turbine.SiteWideWindSpeed = AVG(Sensor1.WindSpeed, Sensor2.WindSpeed, …, SensorN.WindSpeed)
Measurement Point: Site-Wide Vibration Frequency	Blades Measurement Point: Blade Vibration Frequency	Turbine.SiteWideVibration = MAX(Blades1.Vibration, Blades2.Vibration, …, BladesN.Vibration)