When you create a variable or property, you specify its data type. In some cases, you use a built-in data type, such as a number or a Boolean. In other cases, you might want to use an arbitrarily complex data structure by defining a custom named data type you can reuse with other variables or properties.

When you define a custom named data type, the data type must use a unique name. You can add or delete subproperties in each named data type you create without restriction. For example, you might create a Transmitter data type that contains subproperties such as NumChannels and PowerLevel.

TestStand defines a set of standard named data types, which include Error, CommonResults, Path, Expression, and NI_TDMSReference. You can add subproperties to some standard named data types, but you cannot delete any of the built-in subproperties.

Note Modifying the standard named data types might result in type conflicts when you open other sequence files that reference these types.

Although each variable or property you create with a named data type has the same data structure, the variable or property can contain different values.