Re: [CAD_CAM_EDM_DRO] GeckoDrive: seeking practical advice abouttheBig Capacitor !

Jon,
Yes I found that to be the case !
Although the code did a ramp, it was a single ramp and of course the motor could handle it at low rpm but required a "slower" change rate during the final few % to get it to speed required.
I just connected the final power cable ( 200 feet length) and found the 15,000uF helped.
With the advent of PIC18 series, code space(32K), ram(1.6K), and speed(40MHz) are improving the ability to use PIC's for more serious applications.
Best Regards
Hans W

Jon Elson wrote:

> Hans Wedemeyer wrote:
>
> >Thanks for all the replies.
> >
> >Here's what I did since posting the question:-
> >
> >I wanted to confirm my thoughts that a higher Voltage would cure the problem (see original post), so I rigged a 24 Volt 8 Amp Supply in series with the 36 Volt (8 Amps) (thanks Jon)
> >
> >Both supplies are Switchers and regulated they only drop a few millivolts at 8 Amps (High $$$ supplies)
> >I was surprized even with 60 Volts the problem did NOT go away and then turned my attention to the PIC Pulse generator Software and added a Ramp with three steps (each step has it's own slope adjustment
> >and has each slope has 6 Steps).
> >By bringing the motor up slowly (1 Second) and then at about 80% I increased drive frequency more slowly (final 1 second) the motor
> >now runs fine on 36 Volts under full load.
> >
> >
> Smooth acceleration and deceleration ramps are absolutely ESSENTIAL!
> Sharp jumps in speed, or sharp changes in acceleration will cause the
> motors to stall or lose steps. Ragged pulse timing will also cause this.
> Low-powered CPUs and software timing schemes are usable up to
> a couple thousand steps/second, but really start to fall flat in this regard
> beyond that. I demonstrated this at the 2001 NAMES show with my
> digital step rate generator prototype and a Sherline with MicroKinetics
> drivers. Nobody had ever seen one of these machines move over 13 IPM.
> I had it running at 25 IPM with little trouble, having never seen that
> machine or driver before.
>
> Jon
>
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