The Properties tab enables you to define properties for the thing definition. Each property of a thing are the data points related to the thing. For example - Fuel economy, Fuel level are the data points related to a car thing. The properties (data points) collected are displayed in the thing view as graphs(value vs timestamp). Each individual graphs represents one property of the thing.
Properties graph stores historical data for a thing. To view the historical data, click on a property in the Thing view. It is possible to override the presentation values with the values defined in the Properties Tab. For more information, see Presentation.
To define the Properties, do the following:
- From the Developer main screen in the THINGS group, click Thing definitions.
The Thing definitions screen appears. - Under the Standard tab, click on the Properties tab
Enter the following fields:
FieldDescriptionKey The key of the property definition. For more information on formats and limitations of a key, see Field Formats and Limitations. Name The name of the property definition that is displayed on Management Portal pages. Prefix An optional prefix that is displayed before the property on the thing's page in the Management Portal. Suffix An optional suffix that is displayed after the property on the thing's page in the Management Portal. Unit Enter the unit of measure. For example, Time in ms. Calculate aggregates When Calculate aggregates is set to True, all the seven types of aggregates (Average, Weighted Average, Non-zero time weighted average, Sum, Max, Min, and Count) are calculated. For more information on property aggregate. see property.aggregate and thing_def.create View security tags Enter any number of tags to the attribute that controls whether a user or application can view the property. The user or application must have a role that has the same view security tag associated with it in order to view a property with a view security tag associated with it. Update security tags Enter any number of tags to the attribute that controls whether a user or application can update the property. The user or application must have a role that has the same update security tag associated with it in order to update a property with an updated security tag associated with it. Scale Scales the input property value to a required factor. Scaling simplifies the values to more meaningful numerical values. For example, $(value)*1.8+32 converts the values from Celsius to Fahrenheit. Deduplicate Check this option to ignore the duplicate property values (a newly published property value with the same timestamp as an existing property value) Override presentation display Check this option to override the values in the Presentation. When you check this, the dialog gets populated with the values assigned in the Presentation. 
Click the + Property Definition link will display a New property definition section. Selecting the - Delete property definition link will delete the currently displayed property.
- Click Add to add the Property definition.