Specifications

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Allen-Bradley ControlLogix Ethernet Driver Help

<logix array

element tag> {#

rows}{# columns}

tag_1 [2, 3]

2}{5}

highest dimension. Tag_1[2,3]{10} would produce an

array of elements tag_1[2,3] -> tag_1[2,13]

Bit <logix tag

name>.bit

<logix tag name>.

[bit]

tag_1.0

tag_1.[0]

Bit range = 0 to 31

If tag is an array, it must be a BOOL array, otherwise tag

cannot be an array.

String <logix tag

name>/<maximum

string length>

tag_1.Data/4

Stringtag_

1.Data

SINTarraytag_

1/16

Length range = 1 to 65535

The maximum number of characters that can read/write to

the string.

*Since this format may request more than one element, the order in which array data is passed depends on the

dimension of the Logix Array tag. For example, if rows times cols = 4 and the Controller tag is a 3X3 element

array, then the elements that are being referenced are array_tag [0,0], array_tag [0,1], array_tag [0,2], and

array_tag [1,0] in that exact order. The results would be different if the Controller tag were a 2X10 element

array.

Note: For more information on how elements are referenced for 1, 2 and 3 dimensional arrays, refer to Ordering

of Array Data.

Tag Scope

Global Tags

Global tags are Logix tags that have global scope in the controller. Any program or task can access Global tags;

however, the number of ways a Global tag can be referenced depends on its Logix data type and the address

format being used.

Program Tags

Program tags are identical to Global tags except that a Program tag's scope is local to the program in which it is

defined. Program tags follow the same addressing rules and limitations as Global tags, but are prefixed with the

following notation:

Program: <program name>.

For example, Logix tag "tag_1" in program "prog_1" would be addressed as "Program:prog_1.tag_1" in a

client/server tag address.

Structure Tag Addressing

Logix Structure tags (Global or Program) are tags with one or more member tags. Member tags can be atomic or

structured in nature.

This implies that a substructure would be addressed as:

Arrays of structures would be addressed as:

This implies that an array of substructures would be addressed as:

Note: The examples above are only a few of the addressing possibilities that involve structures, and are

displayed to provide an introduction to structure addressing. For more information, refer to Allen-Bradley or

Rockwell documentation.

Internal Tags

Internal tags are not visible in the server configuration, but can be browsed by the OPC client and found under

the <Channel Name>.<Device Name> group. The _CIPConnectionSizeRequested tag reflects the CIP connection

size that was requested. The _CIPConnectionSizeActual tag reflects the actual CIP connection size that is in use.