Galil Motion Control DMC-42 0 Series, User Manual

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Operand Summary - Independent Axis
OPERAND DESCRIPTION
_ACx Return acceleration rate for the axis specified by ‘x’
_DCx Return deceleration rate for the axis specified by ‘x’
_SPx Returns the jog speed for the axis specified by ‘x’
_TVx
Returns the actual velocity of the axis specified by ‘x’ (averaged over 0.25 sec)
Example - Jog in X only
Jog X motor at 50000 count/s. After X motor is at its jog speed, begin jogging Z in reverse direction at 25000
count/s.
#A
AC 20000,,20000
Specify X,Z acceleration of 20000 counts / sec
DC 20000,,20000 Specify X,Z deceleration of 20000 counts / sec
JG 50000,,-25000 Specify jog speed and direction for X and Z axis
BG X
Begin X motion
AS X Wait until X is at speed
BG Z Begin Z motion
EN
Example - Joystick Jogging
The jog speed can also be changed using an analog input such as a joystick. Assume that for a 10 Volt input the
speed must be 50000 counts/sec.
#JOY Label
JG0 Set in Jog Mode
BGX Begin motion
#B Label for loop
V1 =@AN[1] Read analog input
VEL=V1*50000/10 Compute speed
JG VEL Change JG speed
JP #B Loop
Position Tracking
The Galil controller may be placed in the position tracking mode to support changing the target of an absolute
position move on the fly. New targets may be given in the same direction or the opposite direction of the current
position target. The controller will then calculate a new trajectory based upon the new target and the acceleration,
deceleration, and speed parameters that have been set. The motion profile in this mode is trapezoidal. There is
not a set limit governing the rate at which the end point may be changed, however at the standard TM rate, the
controller updates the position information at the rate of 1msec. The controller generates a profiled point every
other sample, and linearly interpolates one sample between each profiled point. Some examples of applications
that may use this mode are satellite tracking, missile tracking, random pattern polishing of mirrors or lenses, or any
application that requires the ability to change the endpoint without completing the previous move.
The PA command is typically used to command an axis or multiple axes to a specific absolute position. For some
applications such as tracking an object, the controller must proceed towards a target and have the ability to change
the target during the move. In a tracking application, this could occur at any time during the move or at regularly
scheduled intervals. For example if a robot was designed to follow a moving object at a specified distance and the
path of the object wasn’t known the robot would be required to constantly monitor the motion of the object that it
was following. To remain within a specified distance it would also need to constantly update the position target it
is moving towards. Galil motion controllers support this type of motion with the position tracking mode. This
mode will allow scheduled or random updates to the current position target on the fly. Based on the new target
the controller will either continue in the direction it is heading, change the direction it is moving, or decelerate to a
stop.
Chapter 6 Programming Motion ▫ 59 DMC-42x0 User Manual