Rockwell Automation GMLC Reference Manual - Manual (Page 497)

Publication GMLC-5.2 - November 1999
460 The Expression Builder
Note: The value currently in the field appears in the Expression
Builder’s Expression = area. The Expression Builder
automatically replaces this value with the expression as you
create it.
The Expression Builder Dialog Box contains the following features:
• Numeric Keypad — To enter numeric values, parentheses,
brackets, decimal point, comma, and certain mathematical opera-
tors.
• Operator Scrolling List — To enter mathematical, logical, and
relational expression operators.
• Tag Explorer — To select the type of variable, I/O, function or
constant and the Tag Window displays.
• Tag Window — To select a particular variable, I/O, function or
constant.
Calculation Accuracy
In the motion controller, all calculations and intermediate results are kept
as double precision floating point values. Calculations and intermediate
results can range between 9.46 x 10
-308 and 1.79 x 10 308 .
The operation of the Expression Builder’s various components are
explained in detail in the following sections.
The Numeric Keypad
The Expression Builder provides a familiar four-function numeric keypad
for entering numbers and the four basic mathematical operations of
addition (+), subtraction (-), multiplication (*), and division (/). Select the
calculator keys as required to enter numbers and operations into your
expression.