A variable type is a model variable from which you can create instances of the variable. Variable instances can contain other specific variables.
Predefined and custom variable types
Each project contains these predefined variable types:
- Analog variable
- Dynamic links
- Node pointer
Custom variable types that you or the application logic create are available only in the project in which you create them.
TIP: Changes to a variable type automatically apply to all instances of the variable. If you delete the variable type, you also delete all the subtypes of the variable type, along with the corresponding instances of the variable.
Variables contain specific data types (for example, a numeric Int32 value or a String value).
By default, every variable contains these attributes:
Name of the variable in the project.
Data type that the variable can contain.
Description of the variable.
Translatable variable name that can appear on the interface at runtime.
Automatically assigned unique identifier.
Value of the data.
For example, you can create a label with a string value of
OKand then create a dynamic link between the variable and the
Textproperty of a
Analog variables are structured variables that represent physical characteristics and ranges.
By default, every analog variable contains these attributes:
Name of the unit of measurement.
Numeric unit of measurement.
Lower limit of the range of values for the variable.
Upper limit of the range of values for the variable.
If True: Values out of the range of not accepted and the previous value is retained. If False: Values out of the range are accepted.
For example, you can create a constrained linear gauge that sources data from a constrained variable. See Develop a constrained linear gauge.
Node pointers references nodes in the project.
The referenced node must be of the type and class defined by these properties:
Type of object or type of variable from which the node is derived
Data loggerobjects have
Storenode pointer properties.
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