Book Contents

Tips for using array tags

To create an array tag, specify how many elements to use, beginning with the first element at the tag’s address.

Use these tag data types for array tags. Use this table to determine how many data elements to address to provide the number of bits you need.

Data Type

Number of bits per element

Character

8

Byte

8

Short Integer

16

Word

16

Integer

32

Double Word

32

For example, if you want to monitor 128 bit positions for an alarm trigger, and you are using the Integer data type, you would append the modifier L4 to the tag name (because 4 x 32 = 128).

You cannot use HMI tags (digital or string tags) for array tags. You must use a direct reference (data server tags) for array tags.

Equivalent data types

Different processors and OPC servers use different terminology for tag data types. This section provides information about equivalent data types that you can use for array tags, with the associated number of bits for each.

Analog HMI tags created in FactoryTalk View

You can view a tag’s data type in the Tag Browser.

Data type

Number of bits

Byte

8

Unsigned Integer

16

Integer

16

3-Digit BCD

16

4-Digit BCD

16

Long Integer

32

PLC and SLC tags

When creating array tags, you can use PLC and SLC tags with this data type:

Data type

Number of bits

Short Integer

16

Data server tags with the Short Integer data type are shown in the Tag Browser with the Item Canonical Data Type of Integer.

To view a tag’s Item Canonical Data Type, in the Tag Browser, right-click the tag and select Properties.

Logix 5000 tags

When creating array tags, you can use Logix 5000 tags with these data types:

Table Heading

Table Heading

SINT

8

INT

16

DINT

32

Data server tags with the data types described in the table are shown in the Tag Browser with the Item Canonical Data Types of Character, Short Integer, and Long Integer, respectively.

See also

The Triggers tab of the Alarm Setup editor

About HMI tag types

About array tags