Rockwell Automation GMLC Reference Manual - Manual (Page 640)

Publication GMLC-5.2 - November 1999
Chapter
31
System Functions
The Expression Builder presents two types of system functions:
• Motion controller functions, which provide indirect addressing of
variables, and direct access to cam profile tables and I/O
• Mathematical Functions, which provide standard algebraic and
trigonometric functions for use in expressions
You include a system function in an expression by selecting System
Functions in the Tag Explorer. In the Tag Window, select the desired
function. In the Expression = window, complete the expression by
inserting the argument (see below). Select OK to set the function.
Like system variables, system functions can be used as elements in
expressions. Unlike variables, however, functions require an argument.
The argument is the element (or expression) upon which the function is
performed. For example, in the following expression the user variable
Cut_Length is the argument of the sine function.:
Sine(Cut_Length)
Important: The argument for motion controller functions is enclosed in
brackets, whereas the argument for mathematical functions is
enclosed in parentheses.
All system functions are strings of standard ASCII characters and can be
typed directly into the expression.
To aid in the use of functions in expressions, a template for proper
construction of the argument appears beneath the Tag Window when you
select a function. The template shows the form and units of the argument.
For example, the template for the sine function indicates that the
argument is an angle measured in radians:
Sine(angle in radians)