On Monday 02 November 2020 04:31:32 andrew beck wrote: > Thanks Jon. > > I am controlling a 1988 fanuc velocity spindle drive. And no Idea > about isolation. Not keen to try it lol. Really I just want a > isolated 0-10v virtual pot like the Mesa 7i76 has. Otherwise I might > daisy chain in a 7i76 just for the spindle io. but that is such a > waste lol. > It sounds as if the pico has the ingrediants to do what you want. And while I've only bought 2 vfd clones, el-cheapo's that just barely have an interface, both are 100% isolated. The nominally 1hp on the lathe is being run with a spinx1 driven by a pwmgen in the 7i90HD, and the 1 hp 24k on the 6040 is actually being run by the 7i76D's electronic pot which is powered from the clone. Both work well and do exactly what lcnc tells them to do. Both vfd's need a run signal, and both need a dir signal, both of which are activatd by taking that line to the clones 0 volt line. So I'm guessing thats a pretty common vfd control format.
In conversations I've had with the vendors, if the pwmgens frequency is in the kilohertz and up range, just enough filtering exists in the 0-10 volt input circuit that one can actually feed the vfd with the pwm and it will integrate the average, the clue for this being that the vfd has a register to change the 0-10 volt input into a 0-5 volt input, then a pwmgen outputting a 5 volt rail to rail can run it to full speed. But I've not actually tried it either. The 7i76D has an excellent convertor, and the 7i90HD is a 3.3 volt card. But the mesa Spinx1 works well there. For the OP, the Pico seems to be the answer, and quite versatile at $50. > On Mon, Nov 2, 2020, 11:03 AM Jon Elson <el...@pico-systems.com> wrote: > > On 11/01/2020 12:46 PM, Ed wrote: > > > On 11/1/20 10:30 AM, andy pugh wrote: > > >> On Sun, 1 Nov 2020 at 04:43, andrew beck > > >> > > >> <andrewbeck0...@gmail.com> wrote: > > >>> On a 7i76 the 0_10v is isolated from the Mesa card I > > >>> think. Is a 7i77 > > >>> similar? I just a bit cagy about connecting up > > >>> electrically to the VFD > > >>> inputs. As I don't want to blow anything. > > > > Most VFDs have isolation between the mains and the control > > inputs. > > You definitely want to make sure of this before connecting > > anything up. > > (Some SCR-type motor drives do NOT have such isolation.) > > > > > Where would a Mesa SpinX1 or a Pico Spindle DAC fit in here? > > > > The Pico Systems Spindle DAC is an 8-bit DAC with parallel > > inputs, and two other inputs that > > enable either positive or negative outputs of 0-10 V. It is > > not isolated, so depends on the > > VFD to be isolated. > > > > Jon > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
