Galil DMC-2X00 - Manual (Page 101)

C (-4000,3000)
R = 1500
B (-4000,0)
D (0,3000)
A (0,0)
Figure 6.3 - The Required Path
Electronic Gearing
This mode allows up to 8 axes to be electronically geared to some master axes. The masters may rotate
in both directions and the geared axes will follow at the specified gear ratio. The gear ratio may be
different for each axis and changed during motion.
The command GA ABCDEFGH specifies the master axes. GR a,b,c,d specifies the gear ratios for the
slaves where the ratio may be a number between +/-127.9999 with a fractional resolution of .0001.
There are two modes: standard gearing and gantry mode. The gantry mode is enabled with the
command GM. GR 0,0,0,0 turns off gearing in both modes. A limit switch or ST command disables
gearing in the standard mode but not in the gantry mode.
The command GM a,b,c,d select the axes to be controlled under the gantry mode. The parameter 1
enables gantry mode, and 0 disables it.
GR causes the specified axes to be geared to the actual position of the master. The master axis is
commanded with motion commands such as PR, PA or JG.
When the master axis is driven by the controller in the jog mode or an independent motion mode, it is
possible to define the master as the command position of that axis, rather than the actual position. The
designation of the commanded position master is by the letter, C. For example, GACA indicates that
the gearing is the commanded position of A.
An alternative gearing method is to synchronize the slave motor to the commanded vector motion of
several axes performed by GAS. For example, if the A and B motor form a circular motion, the C axis
may move in proportion to the vector move. Similarly, if A,B and C perform a linear interpolation
move, W can be geared to the vector move.
Electronic gearing allows the geared motor to perform a second independent or coordinated move in
addition to the gearing. For example, when a geared motor follows a master at a ratio of 1:1, it may be
advanced an additional distance with PR, or JG, commands, or VP, or LI.
Ramped Gearing
In some applications, especially when the master is traveling at high speeds, it is desirable to have the
gear ratio ramp gradually to minimize large changes in velocity on the slave axis when the gearing is
engaged. For example if the master axis is already traveling at 1,000,000 cts/sec and the slave will be
geared at a ratio of 1:1 when the gearing is engaged, the slave will instantly develop following error,
DMC-2X00 Chapter 6 Programming Motion y 91