How can a new user-defined function block be created in ControlLogix?

A new user-defined function block in ControlLogix is created through the "Add Function Block" option in the routine properties. This process allows the user to define a function block that encapsulates specific logic and can be reused in various parts of the application, promoting modular programming. When a user selects this option, they can specify the parameters, local tags, and other relevant properties for the new function block, enabling better organization and clarity in the program structure.

This approach ensures that the function block can be effectively integrated into the existing programming environment and linked to routines appropriately. Furthermore, the ability to define specific inputs and outputs during this process facilitates the integration of the function block with other components in the system, reinforcing its role in the overall control logic.

The other methods mentioned, such as a general "New Function" option or using a shortcut key combination, do not provide the necessary context or capabilities for creating a dedicated user-defined function block. Additionally, altering an existing function block would not create a new block but modify an existing one, which is not the same as creating a new user-defined function from scratch.