Galil Motion Control DMC-42 0 Series, User Manual

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Example - Electronic Gearing
Objective: Run two geared motors at speeds of 1.132 and -0.045 times the speed of an external master. The
master is driven at speeds between 0 and 1800 RPM (2000 counts/rev encoder).
Solution: Use a DMC-4230 controller, where the Z-axis is the master and X and Y are the geared axes.
MO Z Turn Z off, for external master
GA Z, Z Specify Z as the master axis for both X and Y.
GR 1.132,-.045 Specify gear ratios
Now suppose the gear ratio of the X-axis is to change on-the-fly to 2. This can be achieved by commanding:
GR 2 Specify gear ratio for X axis to be 2
Example - Gantry Mode
In applications where both the master and the follower are controlled by the DMC-42x0 controller, it may be
desired to synchronize the follower with the commanded position of the master, rather than the actual position.
This eliminates the coupling between the axes which may lead to oscillations.
For example, assume that a gantry is driven by two axes, X,Y, on both sides. This requires the gantry mode for
strong coupling between the motors. The X-axis is the master and the Y-axis is the follower. To synchronize Y with
the commanded position of X, use the instructions:
GA, CX Specify the commanded position of X as master for Y.
GR,1 Set gear ratio for Y as 1:1
GM,1 Set gantry mode
PR 3000 Command X motion
BG X Start motion on X axis
You may also perform profiled position corrections in the electronic gearing mode. Suppose, for example, that you
need to advance the slave 10 counts. Simply command
IP ,10 Specify an incremental position movement of 10 on Y axis.
Under these conditions, this IP command is equivalent to:
PR,10 Specify position relative movement of 10 on Y axis
BGY
Begin motion on Y axis
Often the correction is quite large. Such requirements are common when synchronizing cutting knives or conveyor
belts.
Example - Synchronize two conveyor belts with trapezoidal velocity correction
GA,X Define X as the master axis for Y.
GR,2
Set gear ratio 2:1 for Y
PR,300 Specify correction distance
SP,5000 Specify correction speed
AC,100000 Specify correction acceleration
DC,100000 Specify correction deceleration
BGY Start correction
Electronic Cam
The electronic cam is a motion control mode which enables the periodic synchronization of several axes of motion.
Up to 7 axes can be slaved to one master axis. The master axis encoder must be input through a main encoder
port.
The electronic cam is a more general type of electronic gearing which allows a table-based relationship between
the axes. It allows synchronizing all the controller axes. For example, the DMC-4280 controllers may have one
master and up to seven slaves.
Chapter 6 Programming Motion ▫ 76 DMC-42x0 User Manual