GE PACSystems RXi User Manual page 137

Chapter 7. CPU Program Data
An index variable can be one of the following:
The following support a variable index:
Dimensional support:
Other features:
124

Symbolic variable

I/O variable

Variable mapped to % memory areas such as %R

Structure element

Array element with a constant index

Array element with a variable index

Alias variable

In the logic of a UDFB or parameterized block: formal parameter

Array elements of any data type except STRING

Parameter array elements of any data type

Alias variables

One-dimensional (1D) formal parameter arrays in the logic of a UDFB or
parameterized block

2D support for the top level of an array of structures and 1D support for a structure
element that is an array. For example:
PQR[a, b].STRU[y].Zed,
where Zed is an element of the array of structures STRU, which itself is an element
of the 2D array of structures PQR.

1D and 2D arrays for other variables

An array with a variable index supports a reference, for example
MyArray[nIndex].X[4],
where .X[4] is the fifth bit of the value stored in MyArray[nIndex]. The bit reference
itself, [4] in the example, must be a constant.

In LD, the following word-for-word changes are supported for array elements with
variable indexes:
Replacing an index variable with another index variable
Replacing an index variable with a constant
Replacing a constant with an index variable
In LD, Diagnostic Logic Blocks support the use of array elements with
variable indexes.
PACSystems* RXi Distributed IO Controller User Manual GFK-2816F