Create An Array - Allen-Bradley 1756-L61 ControlLogix 5561 Programming Manual

Organizing Tags Chapter 2

Create an Array

Term
Array
To expand an array and display its
elements, click the + sign.
To collapse an array and hide
its elements, click the – sign.
Elements of
Timer_Presets
This is a tag that uses the Timer structure (data type).
Tag Name
−
Timer_1
+
Timer_1.PRE
+
Timer_1.ACC
Timer_1.EN
Timer_1.TT
Timer_1.DN
Logix5000 controllers also let you use arrays to organize data.
Definition
A tag that contains a block of multiple pieces of data.
·An array is similar to a file.
·Within an array, each individual piece of data is called an element.
·Each element uses the same data type.
·An array tag occupies a contiguous block of memory in the controller, each element in sequence.
·You can use array and sequencer instructions to manipulate or index through the elements of an array.
·You organize the data into a block of one, two, or three dimensions.
A subscript (s) identifies each individual element within the array. A subscript
starts at 0 and extends to the number of elements minus 1 (zero based).
The following example compares a structure to an array.
Data Type
TIMER
DINT
DINT
BOOL
BOOL
BOOL
Rockwell Automation Publication 1756-PM004D-EN-P - September 2012
This is a tag that uses an array of the Timer data type.
Tag Name
−
Timers
+
Timer[0]
+
Timer[1]
+
Timer[2]
This array contains six
elements of the DINT data
type.
Six DINTs
42367
Data Type
TIMER[3]
TIMER
TIMER
TIMER
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