Re: Which Software?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "torsten98001
<torsten@g...>" <torsten@g...> wrote:

> While back when I was confronted with this
> confusing concept I went to a way to visualize
> the scenario as follows.
>
> visualize the weight of the machine Table and the cutting forces
> involved as a Box of a certain weight sitting on a grit.
>
> The guy in charge of moving this box is your driver electronics.
>
> The effect of a step pulse given for a stepper motor causes
> the guy to give the box a push suppost to send it into the
> next grid field.
> If the Box is heavier then the strength of the guy pushing the
> Box will not move but remain where it is resulting in a missed
> step that can not be detected by feedback less software.
>
> Servo motor drivers go about this a bit different even so the
> results should be the same.
> Servos are controlled by target position.
> So when given a signal to take a step the mover guy moves first
> onto the next grid then he pulls the box towards him.
> Again if the Box is heavier then the guy pulling nothing may

happen.

> However the step will not be lost it will go into a error register
> on the driver. Additional step signals to the mover guy will result
> in him moving farther away from the box trying to pull the box up.
> His arms are sort of like a rubber string streching quiet a bit and
> get stronger as farther he gets away from the box.
> The larger the error register the more current is send to the motor
> to catch up.
>
> The size of this error register depend on the manufacturer of the
> driver, on geckos is 128 steps I belive.
>
> If the error register gets more steps than it can hold it will

reset

> to zero this means all 128 steps in case of the gecko are lost.
>
> So called real feedback software monitor the error registers
> constantly and desides what action to take if the error exeeds
> a certain value. (syncronisation of all axes)
>
> Hope this helps somebody out to make sense of it.
> Good Luck

OK
I'm with you with what you describe - a driver of much
sophistication and superb development(I'm told). My concern is that
the position is still lost as far as the software goes. Working with
3D and losing position along with breaking a tool will most
certainly justify a restart from zero. My wish is that with servos,
the correction or position is totally controlled by software with
feedback from a directly coupled motor to the worktable. Why leave
any part uncoupled? I'm still in the learning process. Should I have
purchased a commercial NC milling machine? Am I asking too much of
this 'hobby' machine?
Thanks yall,

Bill C.