Conveyor-Tracking Programming Conveyor-Tracking Programming This section describes how to access the conveyor-tracking capabilities within eV+. A functional overview is presented that summarizes the extensions to eV+ for Conveyor Tracking. All the eV+ conveyor-tracking keywords are described in detail in the eV+ Language Reference Guide . The conveyor-tracking extensions to eV+ include: l Instructions and functions (there are no monitor commands) l System switch l System parameters Instructions and Functions This section summarizes the eV+ instructions and functions dedicated to conveyor-tracking processing. The belt-related functions return real values.
Belt Variable Definitions The following keywords are used to define the parameters of belt variables. Some parameters are typically set once, based upon information derived from the belt calibration procedure. Other parameters are changed dynamically as the application program is executing. DEFBELT Program instruction that creates a belt variable and defines its static characteristics: nominal transformation, encoder number, and encoder scaling factor. SETBELT Program instruction to set the encoder offset of a belt variable. This defines the instantaneous belt location relative to that of the nominal belt transformation.
WINDOW Program instruction for establishing the belt window boundaries and specifying a window-violation error subroutine. Encoder Position and Velocity Information The following function is used to read information concerning the encoder associated with a belt variable. BELT Real-valued function that returns the instantaneous encoder counter value or the rate of change of the encoder counter value. eV+Language User's Guide, v2.x, 18318-000 Rev A Page 199