Hi Reinhard,
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My contention is that once a coordinated move is dispatched to the controller it is no longer possible to change the A axis rotation rate, it would break the move.
Well, that probabely depends on what communication is possible betwenn mach4 and the motion controller - and of cause it depends on the communication refresh rate.
I don't think that is the case. The trajectory calculated by Mach and the position/velocity/time data once its dispatched to
the controller cannot be altered. The controller may do so, THC is an obvious example where the controller adds or subtracts pulses
from the Z axis pulse stream. In general though it can't be done...if you attempt to change the pulse rate of one axis say, then
the eventual endpoint of the move will be different than Machs assumed endpoint. Unless the controller can report back to
Mach and Mach can accommodate moves that don't go where they are supposed to then Mach has no chance of controlling
the machine. That requires an out of band axis which can be altered WITHOUT affecting a coordinated move of the remaining
axes.
Craig