Rockwell Automation 1398-PDM-xxx IQ Master Version 3.2.4 for IA-2000 and IQ-5000 Positioning Drive Modules, IQ-55 - Manual (Page 156)

134 System Variables & Flags • Introduction
Publication 1398-PM601A-EN-P — October 2000
TUTORIAL
System Variables & Flags
Introduction
What is a System Flag?
Flags that have a predefined function are referred to as system flags. These flags represent conditions in
the ULTRA Plus or IQ. The flags can be tested and some can be set in your program. For example, the
ATHOME flag can be tested to see if the motor is at the home position.
What is a System Variable?
System variables are variables that have a predefined meaning. In most cases the value of these vari-
ables can be read and set in your program. Many of these variables can be set in the Parameter menu.
The values that are set in the Parameter menu become the system default values. Though they can be
changed in the program, when the program ends, the value is returned to the default value.
For example, velocity can be set in the Parameter menu. If you do not set a velocity in your program, the
value set in the Parameter menu will be used for your MOVD and MOVP moves. If you change the
value in your program by executing a VEL command, that value is only in effect while that program is
running. After the program ends the velocity will be restored to the value set in the Parameter menu.
The Personality Module
The personality module contains data (after it is configured) that matches the ULTRA Plus or IQ to a
particular motor. System variables and flags that are set in the Parameter menu are also stored in the per-
sonality module along with all programs and nonvolatile variables and flags. System variables and flags
that are not stored in the personality module are volatile and are calculated or set/cleared during run
time.
Note: When you change the value of a system variable or flag (that is stored in the personality module)
within an application program, the change remains in effect only until the program ends. When the pro-
gram ends, the value is returned to the value in the personality module. The application program only
changes a run-time copy of the system variable or flag.