Timer could be configured for: one shot, re-trigger, continuous. Micro controller have built in comparators and I should use one for sparc detection and the other for start of ionization. Comparator outputs may be connected internally to high resolution timer and there quite many different triggering options. One of the comparator inputs are connected via a resistor divider network to detect gap voltage and the other to DAC inside micro controller.
I guess this very high resolution timer is not needed and ordinary timer would do but if micro controller suitable for power conversion is chosen this is what you get from around a few dollars. Micro controller also have several communication peripherals and I guess UART is the most suitable, I intend to use over an isolation barrier. Regards Nicklas Karlsson On Wed, 9 Mar 2016 16:21:51 +0800 TJoseph Powderly <[email protected]> wrote: > hmm nicklas, its a oneshot not a multivibrator for isopuls. > > its a retriggerable if _not_ isopuls > > make sense? > > yes a hi-rez timer could be used for one shot, but needs voltage drop > detector to trigger it > > tomp > > On 03/09/2016 03:07 PM, Nicklas Karlsson wrote: > > The high resolution timer together with the comparators should be able to > > do exactly what you say if properly configured. I got square wave out > > yesterday and expect to spend a few hours before it's correctly configured > > for EDM. > > > > These micro controllers have only been available for a few years at most, > > they are really good and available from maybe a few dollars each. > > > > Regards Nicklas Karlsson > > > > > > On Wed, 9 Mar 2016 14:10:03 +0800 > > TJoseph Powderly <[email protected]> wrote: > > > >> Niklas Pete, > >> if you want ISOPULS ( isoenergetic pulses that have uniform craters ) > >> then all the worry about frequency is useless > >> > >> if you dont need uniforn surface finish, then ignore this comment > >> > >> if you DO want uniform surface finish, then you do not use repetitive > >> pulse grnerator > >> instead, you wait for ionization ( a kind of indetermonate latency of > >> conduction) > >> THEN start decrementing the ontime. This was the joules delivered are > >> equal ( the energy is equal ) > >> Once the ontime is finished, the current is turned off and the off time > >> is waited > >> THEN you turn on a tiny exciting voltage and wait for another ionization > >> ( and voltage drop ) before starting the next ontime current flow. > >> > >> some pix: > >> http://www.edm-products.com/Dielectrics/ifase/ifase_1.htm > >> look at figure 3 > >> if you wait for the ionization (wait for the voltage to drop) > >> and then deliver current for the duraction of 'ontime', > >> the energy delivered will be uniform, and the surface crater will be > >> uniform > >> if not, the energy per pulse in non-uniform, to the extreme that some > >> pulses deliver nearly no energy! > >> see figure 4, > >> when the strategy is isoenergetic, the current waveform will be uniform > >> and the leading edge of the voltage will vary. > >> if not isoenergetic, the leading edge is static on the scope, > >> but the current wave form will vary. > >> > >> On 03/09/2016 01:59 AM, Nicklas Karlsson wrote: > >>> A microcontroller with suitable peripherals for power conversion is cheap > >>> and do the work much better. I know about: stm32f334, Infineon xmc4xxx > >>> something, maybe texas instruments and Microchip. > >>> > >>> I am working with stm32f334. It have a high resolution timer equal to > >>> about 4GHz clock frequency with a lot of triggering options, DAC, fast > >>> comparators and cost maybe a few dollars. There are also cheap > >>> development boards available. > >>> > >>> I guess spindle off/on signal may be useful to turn off/on generator and > >>> some m-code is useful for the parameters? > >>> > >>> Regards Nicklas Karlsson > >>> > >>> > >>> > >>> On Tue, 8 Mar 2016 16:47:42 +0000 (UTC) > >>> Pete_Gruendeman <[email protected]> wrote: > >>> > >>>> Hi Nicklas: > >>>> I am writing with a request for what might be speculation on your > >>>> part. Given what others have said about pulse frequency, and what is > >>>> written in the Poco tech manuals (frequencies of approximately 8.33- > >>>> 50kHz, derived from varying on and off times), would it be reasonable to > >>>> produce the pulse timing from and at the same time that the PC is > >>>> directing motion control? Erosion pulse generation could be treated as > >>>> another axis-- maybe? I am concerned that the standard parport provides > >>>> rather coarse granularity (increments) between one size and another size > >>>> of pulse, especially as the pulse durations get down to 10 micro seconds > >>>> on a finishing burn. The Mesa 5i20 will create about 200kHz pulses with > >>>> L-cnc input and maybe one of the two parports on it could be repurposed > >>>> as a pulse generator? Maybe it's unrealistic to generate pulses from > >>>> the motion control PC because computing power isn't sufficient? Your > >>>> thoughts? > >>>> > >>>> Pete Gruendeman > >>>> > >>>> -------------------------------------------- > >>>> On Sun, 3/6/16, Nicklas Karlsson <[email protected]> wrote: > >>>> > >>>> Subject: Re: [Emc-developers] EDM gap control (Control parameters) > >>>> To: "EMC developers" <[email protected]> > >>>> Date: Sunday, March 6, 2016, 10:22 PM > >>>> > >>>> On Mon, 7 Mar 2016 > >>>> 10:23:31 +0800 > >>>> TJoseph Powderly <[email protected]> > >>>> wrote: > >>>> > >>>> > off time is > >>>> really dpendant on flushing conditions > >>>> > > >>>> on time causes rougher finer surface finish > >>>> > >>>> I guess this explain it all > >>>> and it also make perfect sense. More powder behind remove > >>>> more material and longer time in between leave more time for > >>>> debri to remove debri. > >>>> > >>>> > >>>> Regards Nicklas Karlsson > >>>> > >>>> > >>>> ------------------------------------------------------------------------------ > >>>> Transform Data into Opportunity. > >>>> Accelerate data analysis in your applications > >>>> with > >>>> Intel Data Analytics Acceleration > >>>> Library. > >>>> Click to learn more. > >>>> http://makebettercode.com/inteldaal-eval > >>>> _______________________________________________ > >>>> Emc-developers mailing list > >>>> [email protected] > >>>> https://lists.sourceforge.net/lists/listinfo/emc-developers > >>>> > >>>> > >>>> ------------------------------------------------------------------------------ > >>>> Transform Data into Opportunity. > >>>> Accelerate data analysis in your applications with > >>>> Intel Data Analytics Acceleration Library. > >>>> Click to learn more. > >>>> http://makebettercode.com/inteldaal-eval > >>>> _______________________________________________ > >>>> Emc-developers mailing list > >>>> [email protected] > >>>> https://lists.sourceforge.net/lists/listinfo/emc-developers > >>> ------------------------------------------------------------------------------ > >>> Transform Data into Opportunity. > >>> Accelerate data analysis in your applications with > >>> Intel Data Analytics Acceleration Library. > >>> Click to learn more. > >>> http://makebettercode.com/inteldaal-eval > >>> _______________________________________________ > >>> Emc-developers mailing list > >>> [email protected] > >>> https://lists.sourceforge.net/lists/listinfo/emc-developers > >> > >> > >> ------------------------------------------------------------------------------ > >> Transform Data into Opportunity. > >> Accelerate data analysis in your applications with > >> Intel Data Analytics Acceleration Library. > >> Click to learn more. > >> http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 > >> _______________________________________________ > >> Emc-developers mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-developers > > ------------------------------------------------------------------------------ > > Transform Data into Opportunity. > > Accelerate data analysis in your applications with > > Intel Data Analytics Acceleration Library. > > Click to learn more. > > http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 > > _______________________________________________ > > Emc-developers mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > ------------------------------------------------------------------------------ > Transform Data into Opportunity. > Accelerate data analysis in your applications with > Intel Data Analytics Acceleration Library. > Click to learn more. > http://pubads.g.doubleclick.net/gampad/clk?id=278785111&iu=/4140 > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Transform Data into Opportunity. 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