Re: [CAD_CAM_EDM_DRO] Re: EMC spindle speed control

Marty Escarcega wrote:

> On 18 May 2001, at 21:17, machines@... wrote:
>
> > --- In CAD_CAM_EDM_DRO@y..., "Marty Escarcega" <escarcega@h...> wrote:
> > Marty
> > There shouldn't be any need for feedback. I run two Ahha's that put
> > out 0 - 10v for the VFD. The machine macro file can be edited so that
> > you get the right voltage for the speed. On mine I also have a remote
> > VFD panel that can show amps, speed, volts etc If I set the machine to
> > say 2500 rpm the machine runs at this speed and only alters slightly
> > under load VFD display will probably vary from 2490 to 2520.
> >
> > John Stevenson
>
> I thought as much John, this is the term open loop? Does EMC
> support Spindle speed? (The output needed to vary the voltage to
> the VFD?)

I'm not sure. I know at one time it was not working. I believe some work
has been done in that area, and it may now work under some conditions.
There was some effort to make a connection between the spindle speed and
the last DAC channel, but only a servo system would have the DACs, anyway.
So, in a straight stepper system, you don't have a DAC, so there's no point
in the software doing anything. I am going to have to do a bunch of work in
the I/O area anyway, so I will attempt to figure this out.

I poked around in the code, and it looks like the speed is set as a parameter
of the spindle speed and direction value that is passed inward from the NML
layer, but I found a place where it is lost, and the speed is set to -1, 0 or +1
based on direction and run/stop. I am working with the 15-Mar-2000 version,
and some of the changes I mentioned above may have been to later versions.

Jon