Change axis resolution on the fly?

I would like to try changing my axis resolution on the fly...is there a way, without losing positioning?

By switching to full stepping during the Homing process, my homing should be (slightly) more consistent. Since my drive has jumpers to change the resolution, I should be able to toggle them "easily" with an i/o pin. How do I change the steps/inch that linuxcnc uses for distance traveled, on the fly?

This will also come in handy to increase the Rapid speeds, since I am running into pulse rate issues. Is there a way to step to a specific step from "home" so when you toggle to full stepping, your (for instance) 1/16 step is aligned with it?

Or is this idea too much to ask of LinuxCNC?

Thanks...

Not sure how full stepping will help your homing process but it would increase your speed.
look here - this seems to be what you want to do:
thread.gmane.org/gmane.linux.distributio...er/45102/focus=45279

Linuxcnc is amazingly flexible.

Chris M

Thanks--that is very good news.

If the home switch is only repeatable within .01mm, and a full step of the motor is .02mm, it will always home on the same step in the same physical location. With 1/16 microstepping on (0.00125mm resolution), the home can vary by 8 steps. That is how lower resolution can improve homing repeatability.

But the resolution switching on the fly should be great for faster rapids, too.

I should point out that in the example I quoted, that Linuxcnc was driving the individual coils of the stepper.
So the example is not quite the same as you would like.
But I bet the principal could still work.
I bet it depends on what happens in the driver when you switch step resolution on the fly.

Chris M