Rockwell Automation GMLC Reference Manual - Manual (Page 476)

Publication GMLC-5.2 - November 1999
Chapter
23
Defining Variables, Constants, and I/O
The Tag Explorer and the Tag Window provide areas in which to view
and select axes system variables and general system variables, and to
define and select user constants, user variables and I/O.
This chapter contains step-by-step procedures for viewing your program’s
variables, constants, and I/O values. The topics in this chapter are:
• Displaying system variables.
• Defining a user variable/constant.
• Defining flex inputs and outputs.
• Defining inputs and output for RIO, SLC, AxisLink, and DH-485
• Using the general watch function.
Understanding System Variables
A variable is a defined place in the controller’s memory that is allocated
to store a number. System variables have predefined meanings. System
variable values are determined during initial program setup, and can
change when you program and execute your diagram.
There are two types of system variables:
Type: Description:
Axis Display information related to a defined axis.
General Display non-axis-related information, for example, data
relating to the CPU, I/O communication program, fault,
task, and fault conditions.