Re: PC to controller comunication protocols

Your performance limitations are due to the fact you're using Basic. Very
inefficient (unless you have a good optimizing compiler.)
--
Phil Mattison
http://www.ohmikron.com/
Motors::Drivers::Controllers::Software

----- Original Message -----
From: jcc3inc <jccinc@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, February 28, 2008 10:34 AM
Subject: [CAD_CAM_EDM_DRO] Re: PC to controller comunication protocols


> Gentlemen:
>
> I too have been working (off and on) on a CNC controller. It is DOS
> based with a max step rate of 4.166 KHz. It does work well, but I'd
> like to have available a higher step rate, and a smoother output
> pulse train. The current max pulse jitter is 240 microsec.
>
> I've been working on an external curcuit which accepts commands of
> up to 31 steps from the parallel port and does linear interpolation
> in X, Y, Z from the sequential commands. The base update rate is 1
> KHz, so there's time for the computer to do other tasks such as
> velocity smoothing and cutter comp. My current IC external circuit
> has added "noise" pulses at the rate of about 12 or so per 100,000
> pulses, not acceptable. So far I have not eliminated the noise. The
> supporting PC program for the above with linear and circular
> interpolation is done, and appears to be OK. The objective for the
> new approach is 31KHz pulse rate and a jitter of 30 microsec or less.
>
> If I knew something about programming microprocessors, they would be
> a better possibility, as the code to handle linear interpolation for
> 3 axes is simple, in BASIC anyway. My programming experience has
> been only in QuickBASIC.
>
> I'd be quite interested in communicating with others of similar
> interests. A spec sheet and screen view of my controller are
> available. I could post them in the files and photos section here.
>
> Regards,
> Jack C.
>
>
>
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