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30. Control Updater Datum Filter

The Control Updater Datum Filter provides a way to update controls with the result of an expression, optionally populating the expression result as a datum property.

This filter is provided by the Standard Datum Filters plugin, which is provided by the solarnode-app-datumfilters package in SolarNodeOS.

30.1 Settings

Control Updater filter component settings The screen shot shows a filter that would toggle the /power/switch/1 control on/off based on the frequency property in the /power/1 datum stream: on when the frequency is 50 or higher, off otherwise.

In addition to the Common Settings, the following general settings are available:

Setting Description
Control Configurations A list of control expression configurations.

Each control configuration contains the following settings:

Setting Description
Control ID The ID of the control to update with the expression result.
Property The optional datum property to store the expression result in.
Property Type The datum property type to use.
Expression The expression to evaluate. See below for more info.
Expression Language The expression language to write Expression in.

30.2 Expressions

See the Expressions guide for general expressions reference. The root object is a DatumExpressionRoot that lets you treat all datum properties, and filter parameters, as expression variables directly.