All you really need to change PWM to volts is a simple RC filter. But really this is a silly design. Think about it, there is a floating point number in the LCNC computer so this gets converted to some integers that set the timers that create a square wave. Then this is filtered to charge a capastior to some voltage and on the VFD there is an analog to digital converter and software to turn this back to a floating point number.
You think there would be some kind of digital interface on the VFD, maybe a serial line so you could send the floating point number and save the effort of a round-trip conversion to analog. On Fri, Apr 1, 2022 at 8:43 PM Leonardo Marsaglia <[email protected]> wrote: > > > > About the purchase, I would love to have the converter ready to use but > > shipping cost to Argentina and taxes for something that little would be > > ridiculously high. I see if I can find some arduino or PIC module ready > to > > use here, if not I'll have to make my own. > > > I meant, something that little it's not worth the shipping and taxes unless > I use a cheap shipping method which will take a month to arrive. But sadly > I need this thing to start working next week. > > El sáb, 2 abr 2022 a las 0:37, Leonardo Marsaglia (<[email protected] > >) > escribió: > > > I found a firmware file on the mesa website that traded the 6th > >> stepgen for a pwm. You can get a module on ebay for about $12 that > >> converts that to 0-10v. Just set mine up that way and it's working > >> great.. > > > > > > Hi Joel, > > > > Well, the one in the forum uses P1 for the PWM output so all the > > stepgens are still available. > > About the purchase, I would love to have the converter ready to use but > > shipping cost to Argentina and taxes for something that little would be > > ridiculously high. I see if I can find some arduino or PIC module ready > to > > use here, if not I'll have to make my own. > > > > Stay well! > > > > > > > > El vie, 1 abr 2022 a las 23:59, Joel Jacobs (<[email protected]>) > escribió: > > > >> I found a firmware file on the mesa website that traded the 6th > >> stepgen for a pwm. You can get a module on ebay for about $12 that > >> converts that to 0-10v. Just set mine up that way and it's working > >> great.. > >> Joel > >> > >> On Fri, Apr 1, 2022 at 1:03 PM gene heskett <[email protected]> > wrote: > >> > > >> > On Friday, 1 April 2022 09:51:50 EDT Leonardo Marsaglia wrote: > >> > > Hi guys, I hope you're all doing well > >> > > > >> > > Quick question to define a little issue I have. I purchased a VFD > that > >> > > I wrongly thought had a pulse train input for speed reference. Turns > >> > > out that feature it's optional so I need an additional card to have > >> > > it. By the way this Simphoenix E280/E580 VFD can reach more than 800 > >> > > hz so it's a good candidate for high speed spindles (which is the > main > >> > > reason why I purchased it). > >> > > > >> > > So my question is: Is it that difficult to modify the firmware on > the > >> > > 7i95 to add at least 1 PWM generator so I can easily convert that to > >> > > analog voltage? Because if not, I need to make a frequency to > voltage > >> > > converter which is a little trickier. I prefer the PWM option of > >> > > course. > >> > > > >> > > Thanks as always for your help and knowledge :) > >> > > >> > Have you actually tried to feed a software PWM into the analogue > input? > >> > They are usually filtered well enough to do that by filtering to the > >> > average of a fast PWM. I have a huan yang clone on my 6040 I did that > >> > with for a couple months before I found we had an rs485 driver that > >> > worked even better. You may need to buffer that 5volt p-p signal in a > >> > transistor to bring the swing up to the 10 volts the vfd needs, but > the > >> > vfd also can supply 12 volts to do that with. You'll need two > >> transistors > >> > to keep from inverting the speed range, look up a long tailed invertor > >> on > >> > google. Better yet, a ttl input cmos output AND gate, will give you a > >> > full rail to rail signal. Check the docs from the vfd, you may need to > >> do > >> > the same with the dir signal. Generally both the run and dir signals > are > >> > energized by pulling that input down to ground from its open circuit > of > >> > 10 volts. Or use a Mesa SpinX1. I'm using that on my sheldon to do the > >> > reversal when rigid tapping in 1/4 turn at 100 spindle rpms. Response > >> > speed if the vfd is tuned correctly, is not a problem. Generally, they > >> > are not tuned "Out Of The Box". > >> > > >> > Take care and stay well Leonardo. > >> > > >> > Cheers, Gene Heskett. > >> > -- > >> > "There are four boxes to be used in defense of liberty: > >> > soap, ballot, jury, and ammo. Please use in that order." > >> > -Ed Howdershelt (Author, 1940) > >> > If we desire respect for the law, we must first make the law > >> respectable. > >> > - Louis D. Brandeis > >> > > >> > > >> > > >> > > >> > > >> > _______________________________________________ > >> > Emc-users mailing list > >> > [email protected] > >> > https://lists.sourceforge.net/lists/listinfo/emc-users > >> > >> > >> _______________________________________________ > >> Emc-users mailing list > >> [email protected] > >> https://lists.sourceforge.net/lists/listinfo/emc-users > >> > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
