Galil Motion Control programming Page 11
Technical Reference
Motion Programming
www.galilmc.com
/
Galil Motion Control, Inc.
15
Proportional Motion
Another useful feature of motion controllers is their ability to gen-
erate additional controlled motion in proportion to the vector
speed.This feature is useful with the generation of helical motion
whereby two axes form circular motion and a third axis moves at a
proportional velocity in the vertical direction. Proportional velocity
is also useful in applications such as dispensing glue. Suppose that
the motion in the XY plane is performed at variable speed; in order
to produce uniform amounts of glue per unit of length, it is neces-
sary to drive the glue pump at a rate that is proportional to the
vector speed in the XY plane.
Electronic Gearing
Many applications require motion between axes to be synchro-
nized or geared. Electronic gearing allows up to seven axes to be
geared electronically to one master axis which may or may not be
a motor controlled by the DMC.The master axis (GA) can rotate in
both directions and the geared axes will follow at the specified
ratios (GR).The gear ratio can be changed during motion. A geared
axis can also simultaneously perform an independent or vector
move for the precise synchronization required in flying-shear
applications.The electronic gearing mode eliminates mechanical
gears and is useful for gantry applications.The following example
shows a program for an electronic gearing application.
Consider an XYZ system where the resolution is 100 count/mm for all
axes.The objective is to generate a helical motion with 10 full turns
of 5 mm radius in the XY plane and a height of 20 mm in the Z direc-
tion.The vector speed in the XY plane is 40 mm/sec. and both the
vector acceleration and deceleration equal 1000 mm/sec
2
.The
motion parameters can be expressed in units of resolution by the
parameters:
radius = 5 mm = 500 counts
vector speed = 20 mm/sec = 2000 count/sec
accel/decel = 1000 mm/sec
2
= 100,000 count/sec
2
To determine the gear ratio, note that the path in the XY plane consists
of 10 circles with a radius of 5 mm resulting in a total length of 314 mm.
Also note that the motion in the Z direction is 20 mm.The ratio between
the two motions is
20
ratio = ____ = 0.0637
314
The required motion is generated by the following program.
INSTRUCTION
INTERPRETATION
#HELICAL
Label
VMXY
Define XY plane
GA,, S
Select master motion
GR,,0.0637
Set Z as follower
CR 500,0,3600
Define 10 circles
VE
End of path
VS 2000
Vector speed
VA 100000
Vector acceleration
VD 100000
Vector deceleration
BGS
Start the motion
EN
End program
Example--Proportional Motion
