Galil Motion Control DMC-42 0 Series, User Manual

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keeps track of this position phase lag with the _GP operand. The following example will demonstrate how the
command is used.
Example – Electronic Gearing Over a Specified Interval
Objective Run two geared motors at speeds of 1.132 and -.045 times the speed of an external master. Because the
master is traveling at high speeds, it is desirable for the speeds to change slowly.
Solution: Use a DMC-4230 controller where the Z-axis is the master and X and Y are the geared axes. We will
implement the gearing change over 6000 counts (3 revolutions) of the master axis.
MO Z Turn Z off, for external master
GA Z, Z Specify Z as the master axis for both X and Y.
GD 6000,6000 Specify ramped gearing over 6000 counts of the master axis.
GR 1.132,-.045 Specify gear ratios
Question: What is the effect of the ramped gearing?
Answer: Below, in the example titled Electronic Gearing, gearing would take effect immediately. From the start of
gearing if the master traveled 6000 counts, the slaves would travel 6792 counts and 270 counts.
Using the ramped gearing, the slave will engage gearing gradually. Since the gearing is engaged over the interval of
6000 counts of the master, the slave will only travel ~3396 counts and ~135 counts respectively. The difference
between these two values is stored in the _GPn operand. If exact position synchronization is required, the IP
command is used to adjust for the difference.
Command Summary - Electronic Gearing
COMMAND DESCRIPTION
GA n Specifies master axes for gearing where:
n = X,Y,Z or W or A,B,C,D,E,F,G,H for main encoder as master
n = CX,CY,CZ, CW
or CA, CB,CC,CD,CE,CF,CG,CH for commanded position.
n = DX,DY,DZ or DW or DA, DB, DC, DD, DE, DF,DG,DH for auxiliary encoders
n = S or T for gearing to coordinated motion.
GD a,b,c,d,e,f,g,h Sets the distance the master will travel for the gearing change to take full effect.
_GPn
This operand keeps track of the difference between the theoretical distance traveled if
gearing changes took effect immediately, and the distance traveled since gearing
changes take effect over a specified interval.
GR a,b,c,d,e,f,g,h Sets gear ratio for slave axes. 0 disables electronic gearing for specified axis.
GM a,b,c,d,e,f,g,h X = 1 sets gantry mode, 0 disables gantry mode
MR x,y,z,w Trippoint for reverse motion past specified value. Only one field may be used.
MF x,y,z,w Trippoint for forward motion past specified value. Only one field may be used.
Example - Simple Master Slave
Master axis moves 10000 counts at slew speed of 100000 counts/sec. Y is defined as the master. X,Z,W are geared
to master at ratios of 5,-.5 and 10 respectively.
GA Y,,Y,Y Specify master axes as Y
GR 5,,-.5,10 Set gear ratios
PR ,10000
Specify Y position
SP ,100000 Specify Y speed
BGY Begin motion
Chapter 6 Programming Motion ▫ 75 DMC-42x0 User Manual