Re: [CAD_CAM_EDM_DRO] wave drive

John:

>>> How does this differ from wave driving?

It doesn't really. But most wave drive is digital, not proportional. The
wave drive systems most commonly found are as in the MaxNC type of
controller. It accepts a 4 signals, which are usally just transistors which
give full current when switched on and none when off. While this can work
well with the proper control sequence, it is generally a poor system of
control for a couple of reasons, one, it requires 4 pins of control for each
motor. Second, the current in most wave drives is not chopper controlled,
but simply resistive limited. This makes matching the driver to the motor
very important and even when matched power is wasted in the limiting
resistors. While your right, in theory, that it could be done correctly and
have the same responce, step/dir is the best solution in practical use. It
is arguable that microstep is really a fancy wave drive when you consider
only the final output stage, the properties that make wave drive ineffective
for most uses are the complexity of its implementation from a control
perspective. The simplest step/dir controls are wave drive, they simply have
a sequencer in their front end. True microstep is the proportional control
you describe. I guess its all a matter of semantics.., but for speed, you
cannot beat microstep due to the phase changes from step to step being much
less pronounced , therefore being much more tolerant to phase variations in
the input pulse stream. This helps keeps resonance down to a minimum and
allows for greater speed.

Just my opinion of course, haven't met a wave drive guy yet who doesn't like
microstep better in a comparison test though...
Art
www.artofcnc.ca