Chapter 3. Program Data
GFK-2950C
February 2018
35
Dimensional support:
▪
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
Other features:
▪
An array with a variable index supports a bit 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.
Where Array Elements with Variable Indexes are Not Supported:
The following do not support array elements with variable indexes:
▪
Indirect references
▪
EGD variables
▪
Reference ID variables (RIVs) and I/O variables when accessed in the Hardware Configuration
Note:
In logic, RIVs and I/O variables support variable indexes.
▪
STRING variables
A variable index cannot be one of the following:
▪
A math expression. For example, ABC[GH+1] is not supported.
▪
An indirect reference. For example, W[@XYZ] is not supported.
▪
A bit reference. For example, ABC[DEF.X[3]] is not supported.
Note:
You can use a bit reference on an array element designated by a variable index. For example,
ABC[DEF]
.X[3]
is supported.
▪
An array head. For example, if MNP and QRS are arrays, MNP[QRS] is not supported, but
MNP[QRS[3]] and MNP[QRS[TUV]] are, where TUV is an index variable.
▪
A negative index. This generates a run-time non-fatal CPU fault.
▪
A value greater than Y, where Y = [number of array elements] - 1. This generates a run-time non-
fatal CPU fault.
Summary of Contents for PACSystems RSTi-EP
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