All current generation Galil motion controllers have at least 1 imaginary axis, called the N axis. The Econo and Optima series motion controllers both have 1 while the Accelera series have 2 imaginary axes (M and N axes) regardless of the number of true axes. An imaginary axis is essentially an extra profiler and does not have any encoder inputs. Two common uses for imaginary axes are detailed below

1. Sinusoidal Motion

While drawing a circle, both the X and Y axis move in a sinusoidal motion. Using the vector mode(VM), and the circle command(CR) we can take advantage of this to create our own sinusoidal motion. Vector mode requires two axes be defined for vector motion, but if we only want a single axis of sinusoidal motion we would need to "waste" another axis. Instead, we can use the imaginary axis as the other component of our vector plane.

VMXN;'X and N are our two vector components
CR1000,10000,10000
VE
BGS
EN


Adjusting the different components of CR will change the frequency and amplitude of the sin wave. By taking advantage of the vector buffer we can realize infinite sinusoidal motion.

2. Gearing master

An imaginary axis can be used as a master for gearing. This can be useful when it is required to move an axis with two different modes of motion. For example, in an XY stage moves are made in vector mode. However at times it can be useful to remain in vector mode and still jog one of the axes, perhaps after an input, but while in vector mode(VM) it is not permitted to enter jog mode(JG). To solve this we can use an imaginary axis as a gearing master.

GAN;'N is the master of the X axis
GR1;'The gear ratio is 1
VMXY
VP1000,1000
BGS
AI1;'Wait until input 1 goes high
JGN=1000;'Jog the imaginary axis which in turn jogs the X axis
BGN
EN