I have two different types of mill controllers in my life. One was a FADAL, the other Linuxcnc.
On the FADAL control, with the rotary axis (I have an A rotary axis) the sign determined direction. In other words, A45 and A-45 were both the same absolute positions in space. BUT the sign determined whether the move was CW or CCW to get to that position.
Many other controllers use the principle of "magnitude determines direction". In other words, the controller will always turn the shortest direction to get to the A axis position. Because of this, many post processors have settings to cater for this and therefore always break rotary moves into shorter segments (at least less than 180 degrees) to make sure the axis continues to turn in the correct direction during the move.
How does linuxcnc handle this and how does one define direction in the case of a single/continuous greater than 180/360 degree move?
