Registering a Virtual Measurement Point¶

A virtual measurement point is a non-model measurement point defined by the expression calculated based on one or more parameters. Parameters can be model measurement points, constants, and attributes. Only by registering virtual measurement points in Common Data Service can these measurement points be queried through Common Data Service APIs. You can register virtual measurement points in batches by uploading a template file.

Note

A virtual measurement point is not saved in the model, nor does it require storage. It is calculated in real time by Common Data Service during query. Therefore, virtual measurement points can only be used in lightweight calculation scenarios like device state mapping and PowerRatio=ActivePower/Capacity.
Common Data Service supports querying virtual measurement points, as well as the latest data and time series data of the measurement points on the models mapped with registered object types.

Prerequisites¶

You need to be assigned the required asset permission and operation permission, and a menu group containing the Virtual Points menu. If not assigned, contact the application administrator.
You need to learn the following best practices to ensure point query performance.
- It is recommended that a virtual point expression references no more than 3 model points.
- It is not recommended that you create virtual measurement points based on model points of the Generic type.
- It is recommended that you perform pre-calculation and generate model measurement point data after analyzing user scenario and evaluating query performance.

Procedure¶

Select Meta Data > Virtual Points from the left navigation pane.
Select the Public Points or Private Points tab according to the effective scope of the target measurement point, and click Import. For more information about the difference between public and private points, see Public/Private Points.
Click Download in the pop-up window and choose to download an Excel or a JSON template file.

Enter the following information in the template file.

Field Name	Identifier	Required/Optional	Description
Point	measurementPoint	Required	The identifier of the point, which needs to be unique under the same object type within the same (public/private) effective scope.
Point Chinese/English/Japanese/Spanish Name	zh_CN/en_US/ja_JP/es_ES	English and Chinese names are required	The point name in different languages.
Object Type Identifier	mdmType	Required	The identifier of the asset type that the point belongs to. You can go to Meta Data > Object Types to view the object type identifier.
Object Type Name	mdmTypeName	Optional	The name of the asset type that the point belongs to. You can go to Meta Data > Object Types to view the object type name.
Interval	interval	Required	The query intervals supported by the point. Use these intervals: RAW (raw data), 1m (1 minute), 5m (5 minutes), 10m (10 minutes), 15m (15 minutes), 30m (30 minutes), H (hour). Separate multiple intervals by commas, for example, RAW,1m,5m,10m.
Time Aggregation Methods	timeAggMethods	Required	Specify how the data is aggregated when queried by a designated interval. Use these aggregation methods: avg, sum, max, min, first, last.
MDM Aggregation Methods	mdmAggMethods	Optional	Specify how the data is aggregated when multiple objects are queried. Use these aggregation methods: sum, avg, max, min.
Expression	expression	Required	Configure an expression based on model points and attributes. Use this format to reference a model point: `Point['ModelPointIdentifier']`. Use this format to reference an attribute: `Attribute['AttributeIdentifier']`. You can reference multiple model points and attributes in one expression. For example, the expression of the `Power Ratio` point is configured as: #{SUM#(Point[‘GenActivePW’]*1000#) / Attribute[‘capacity’] / 10.0}
Signal Type	signalType	Required	The type of the point. Use these point types: AI (Analog Input, AI points usually ingest numerical data), DI (Digital Input, DI points usually ingest device status data), PI (Pulse Input, PI points are usually used for calculating electric power data), Generic (points ingesting all other types of data, especially data of non-numerical types).
Enumerate	enumerate	Optional	If the point is enumerated, describe the supported enumeration values.
Is Future Data Available	includeFutureData	Optional	Fill in `Y` if the point data in the future can be queried, such as predictive data. fill in `N` if the historical point data before the current time can be queried only.
Unit	units	Optional	Fill in the unit of the point data by referring to EnOS Built-in Units.
Application Dependency	applicationDependency	Optional	The application that the point depends on. Separate multiple applications by commas.
Application Version Dependency	applicationVersionDependency	Optional	The application version that the point depends on. Separate multiple versions by commas.
Data Type	dataType	Required	The data type of the point differs according to the specified point type. Use these data types: Int (for AI or DI points), Double (for AI or PI points), String (for Generic points only).

Note

The “Org ID”, “Org Name”, “Updated On”, and “Updated By” fields in the template file can be left blank and will be filled by the system after upload.

Click Upload in the pop-up window. Select the filled template file and click OK.

Results¶

Once registered, the virtual point appears in the point list. You can view its details and perform the following actions on it.

Edit the virtual point: Click Export, modify the template file as required, and import the modified file. The points with the same identifiers will overwrite the existing points, and the points with different identifiers will be added.
Delete the virtual point: Click Delete of the target point. Deleted points cannot be restored.