Re: [CAD_CAM_EDM_DRO] emc with camtronics just too strange

bgroover1 wrote:

> With much help from the list I worked on my setup again last night.
> I even ran a copy of stepster to insure that I hadn't develped
> equipment problems(which worked fine, stepped off .001 no problem).
> So I still cann't move .001 at a time with emc reliably. But here is
> the strange part. I can move .1 with no problem(less than .001 error
> over 5+ moves in one direction). In order to do that I have to set
> the axis speed and override just right(not too slow but not too fast)
> but it is completely repeatable.
>
> My setup is such that 4000 steps is 1 inch or 4 steps to the .001
>
> It seems like I need to tune steppermod? I am going to try yet
> another computer if I can. It shouldn't make any difference but this
> one is a P 150 pro which is kind of an odd bird.

Why are you so concerned with .001" steps? Can your machine really
hold such fine accuracy?

I think you have a sort of deadband problem, here. When you make a
jog move of .001", the velocity is extremely low. Try changing the
velocity when you do the .001" test. I suspect it will make a difference.
What is happening is that steppermod simulates in software a servo
system with finite gain. When you move extremely slowly for a small
amount, it may not overcome the simulated friction, so the machine
may or may not move. If you increase the P term in the .ini file, it
will probably fix this problem. This may cause problems at high
speed, so you may need to reduce the acceleration value to prevent
exceeding the acceleration your motors/drivers can provide.

Try changing the P term and see what happens.

Jon