X hits on this document

473 views

0 shares

4 downloads

0 comments

54 / 133

Allen-Bradley ControlLogix Ethernet Driver Help

54

Description

Range

Single bit value

VT_

0, 1

BOOL

Signed 8 bit value

VT_UI1

-128 to 127

Signed 16 bit value

VT_I2

-32,768 to 32,767

Signed 32 bit value

VT_I4

-2,147,483,648 to 2,147,483,647

Signed 64 bit value

VT_I8

–9,223,372,036,854,775,808 to

See Also: Logix Advanced Addressing

VT R4

_

Atomic Data Type

BOOL

SINT INT DINT LINT

REAL

32 bit IEEE Floating point

9,223,372,036,854,775,807

1.1755 E-38 to 3.403E38, 0, -3.403E-38 to -1.1755

Client/Server Tag Address Rules Logix Tag names correspond to Client/Server Tag addresses. Logix Tag names (entered via RSLogix5000) follow the IEC 1131-3 identifier rules. Client/Server Tag addresses follow these same rules. They are as follows:

l

l

l

l

l

Must begin with an alphabetic (A-Z, a-z) character or an underscore (_). Can only contain alphanumeric characters and underscores. Can have as many as 40 characters. Cannot have consecutive underscores. Are not case sensitive.

Client/Server Tag Name Rules Tag name assignment in the server differs from address assignment in that names cannot begin with an underscore.

Note: Logix Tag names should be kept to a minimum in size for optimum performance. The smaller the name, the more requests that will be able fit in a single transaction.

Important: Symbolic Mode users should keep the Client/Server Tag addresses below 400 characters. For example, tagarray[1,2,4].somestruct.substruct_array[3].basetag.[4] is 57 characters in length. Since a packet can only hold 500 data bytes, any overhead bytes that need to be added to the packet can greatly diminish the room available to the characters themselves. By keeping the address below 400, the tag request will remain complete and valid.

See Also: Performance Optimizations

Address Formats

There are several ways to address a Logix Tag statically in the server or dynamically from a client. The format used depends on the type and usage of the tag. For example, the bit format would be used when accessing a bit within a SINT-type tag. For information on address format and syntax, refer to the table below.

Note: All formats except for Array and String are native to RSLogix5000. Therefore, when referencing an atomic data type, an RSLogix 5000 tag name could be copied and pasted into the server's tag address field and be valid.

Syntax <logix tag name>

Example tag_1

Notes Tag cannot be

an array.

<logix Array Tag name> [dim 1, dim2, dim 3]

tag_1 [2, 58, 547] tag_1 [0, 3]

Dimension Range = 1 to 3 | Element Range = 0 to 65535

<logix Array Tag name> {# columns} <logix Array Tag name> {# rows}{# columns}

tag_1 {8} tag_1 {2}{4}

Dimension Range = 1 to 2 | Element Range = 1 to 65535

Format Standard

Array Element

Array w/o Offset*

The number of

www. kepware.com

Document info
Document views473
Page views495
Page last viewedSun Dec 04 00:02:52 UTC 2016
Pages133
Paragraphs5515
Words40931

Comments