ControlLogix Tag Addressing

Global controller tags are tags that have global scope in the controller. Any program (task) can access the global tags. The number of ways a global controller tag can be referenced is dependent on its data type in the controller and the address format used. See the driver help section on Address formatting for more detail.

Program Tags

Program tags are identical to global tags except a program tag's scope is local to the program its defined in. Program tags follow the same addressing rules and limitations as global tags. The only difference is that program tags are prefixed with the following notation:

Program:program_name.tag_name

For example, tag_1 in program prog_1 would be addressed as Program:prog_1.tag_1 (using the standard address format in this example).

Structure Tag Addressing

Structure tags, global or program, are tags with 1 or more member tags. Member tags can be basic or structured in nature. The structure notation can precede any of the above address classes:

structure_name.base-type_tag

This implies that a substructure would be addressed as:

structure_name.substructure_name.base-type_tag

Arrays of structures would be addressed as follows:

structure_array_name[dim1, dim2, dim3].base-type_tag

Again, this implies that an array of substructures would be addressed as:

structure name.substructure array name[dim1, dim2, dim3].base-type_tag