Re: emc help

Hello,
Yes i do know the difference and you can see all the caluation in a
previous messages showing how the pulse rate was arrived at.
If you happen to have a source for encoders in the mhz rate i will
gladly look at them.
But to give you some example i use rod 426 hiedhain encoders with
between 1000-10000 line counts/300khz max about 225$ each.
I have used a few dynpars but they are rated at 150khz.

I have tried to explain what i originally ment with the parallel port
,it just doesnt matter anymore.
Regards,
Greg


--- In CAD_CAM_EDM_DRO@yahoogroups.com, Robin Szemeti <list@r...>
wrote:

> On Saturday 31 January 2004 01:07, Greg wrote:
> > -
> > Hello,
> > Whoever wrote this doesnt know much about encoders.
> > I use hiedhain encoders and they are expensive but they have a max
> > encoder freq of 300khz which is double the normal spec of most

other

> > encoders.
>
> well, you cant have looked very far ... most go to *at least* 10mhz

or so ...

> are you *sure* you know the diference between pulse rate and ppr?
>
> > The only exception to this i have found is laser encoders made by
> > canon.(Way to expensive)
>
> see above
>
> > Also if you check your specs on the STG board the max enoder freq

is

> > not 10 mhz but much lower.
>
> not sure that is correct either ...
>
> > And of course the parallel port could not run at these speed.
>
> no, but you would not use a paralell port directly to read the

encoders,

> you'd use the paralell port to read a register that was constantly

updated by

> the encoders, that way the paralell port only needs to run at servo

loop rate

> (10 khz or so) which it can do easily ...
>
> > And even the pico systems is limited to 300khz
> >
> > Regards,
> > Greg
> >
> > -- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>

wrote:

> > > > From: Jon Elson <elson@p...>
> > >
> > > <s>
> > >
> > > > Most encoder counters can handle 300,000 to 1 million encoder
> > > > counts/second. So, that would be 30 to 100 inches a second, or
> >
> > 1800 to
> >
> > > > 6000 IPM. Is that enough for you?
> > >
> > > STG claims 10 MHz.. In theory you can multiply these values by

10

> >
> > so you
> >
> > > could be dealing in miles per minute.
> > >
> > > Ray
> >
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