Creating an Alias Parameter for a Local Tag

Alias parameters simplify connecting local tags to an Input or Output tag that is commonly used in the Add-On Instruction’s application without requiring that manual code be created to make the association. Aliases can be used to define an Input or Output parameter with direct access to a local tag or its member.
Changing the value of an alias parameter changes the data of the local tag or local tag member it represents and vice versa.

Alias parameters are subject to these restrictions:

· Alias parameters must be either Input or Output parameters.
· You can only create an alias parameter for a local tag or its member.
· Only one Input and one Output parameter may be mapped to the same local tag or the same member of a local tag.
· Only BOOL, SINT, INT, DINT, and REAL data types may be used.
· Alias parameters may not be constants.
· The External Access type of an alias parameter matches the External Access type of the local tag to which it is mapped.