Allen-Bradley ControlLogix Ethernet Driver Help
Automatic Tag Database Generation
The Allen-Bradley ControlLogix Ethernet Driver can be configured to automatically generate a list of server tags within the server that correspond to device-specific data. The automatically generated tags are based on the Logix Tags defined in the Logix device, and can be browsed from the OPC client. Logix Tags can be atomic or structured. Structure and array tags can quickly increase the number of tags imported (and therefore the number of tags available in the server).
Note: ENI/DH+, ControlNet Gateway, and MicroLogix 1100 models do not support automatic tag database generation: only ENI ControlLogix, CompactLogix, and FlexLogix models do.
Atomic Tag -> one-to-one-> Server Tag Structure Tag -> one-to-many -> Server Tags Array Tag -> one-to-many> -> Server Tags
Note: For more information on the Database Creation settings, refer to the server help file.
The server tags created by automatic tag generation can follow one of two hierarchies: Expanded or Condensed. To enable this functionality, make sure "Allow Automatically Generated Subgroups" is enabled in Device Properties. The default setting is Expanded Mode.
In Expanded Mode, the server tags created by automatic tag generation follow a group/tag hierarchy consistent with the tag hierarchy in RSLogix 5000. Groups are created for every segment preceding the period as in Condensed Mode, but are also created in logical groupings. Groups created include the following:
Global (controller) scope Program scope Structures and substructures Arrays
Note: Groups are not created for .bit addresses.
The root level groups (or subgroup levels of the group specified in "Add generated tags to the following group") are "Prgm_<program name>" and "Global". Each program in the controller will have its own "Prgm_<program name>" group. The driver recognizes this as the first group level.
Basic Global Tags (or non-structure, non-array tags) are placed under the Global group; basic Program Tags are placed under their respective program group. Each structure and Array Tag is provided in its own subgroup of the parent group. By organizing the data in this fashion, the server's tag view mimics RSLogix5000.
The name of the structure/array subgroup also provides a description of the structure/array. For instance, an array tag1[1,6] defined in the controller would have a subgroup name "tag1_x_y"; x signifies dimension 1 exists, and y signifies dimension 2 exists. The tags within an array subgroup are all the elements of that array (unless explicitly limited). The tags within a structure subgroup are the structure members themselves. If a structure contains an array, an array subgroup of the structure group will be created as well.
With a complex project, the tag hierarchy could require a number of group levels. The maximum number of group levels created by automatic tag generation is seven. This does not include the group specified in "Add generated tags to the following group". When more than seven levels are required, the tags will be placed in the seventh group (causing the hierarchy to plateau).
Array Tags A group is created for each array that contains the array's elements. Group names will have the notation: <array name>_x_y_z where:
x_y_z = 3 dimensional array x_y = 2 dimensional array x = 1 dimensional array
A r r a y T a g s w i l l h a v e t h e n o t a t i o n : < t a g e l e m e n t > _ X X X X X _ Y Y Y Y Y _ Z Z Z Z Z . F o r e x a m p l e , e l e m e n t t a g 1 [ 1 2 , 2 , 9 8 7 would have the tag name "tag1_12_2_987". ]