National Instruments NI-Motion - Manual (Page 126)

Chapter 10 Electronic Gearing and Camming
NI-Motion User Manual 10-4 ni.com
Changing a gear ratio on-the-fly during absolute gearing allows you to
quickly synchronize the slave axis with the master axis.
Note When the gear ratio is changed on-the-fly, the slave axis moves at full torque to the
new position.
Gear Master
An axis can be geared to another axis, or to an encoder or ADC.
When you gear an axis to another axis, the slave axis follows the trajectory
generation of the master axis. For example, if you manually move the
master axis, the slave axis does not move because the trajectory generator
of the master axis is not active.
When you gear an axis to an encoder, or feedback device, the slave axis
follows the feedback generated by the encoder. If the encoder detects
movement, the slave moves proportionally to information returned by the
encoder. For example, if you twist the master axis connected to the encoder,
the slave axis also turns because it is using the position information
gathered by the encoder.
When an axis is geared to an ADC, the slave axis follows the binary value
of the ADC as if it were a position. For example, if the binary code for 2 V
is 6553, the slave axis tracks to this position.