On Sunday 27 December 2020 08:26:47 Gene Heskett wrote: > On Sunday 27 December 2020 07:46:04 andy pugh wrote: > > On Sun, 27 Dec 2020 at 06:10, Gene Heskett <ghesk...@shentel.net> > > wrote: > > > After reading several different versions of the manual I've found > > > online, and killing another tree for hard copy BIG enough to read, > > > it becomes obvious that the common point reference for the speed > > > input AND the MultiFunction terminal labeled VO in my unit, all > > > use the AGM terminal as a commom reference, while the FWD(RUN in > > > my case)/REV are referenced to the DCM terminal. > > > > Do you mean ACM (analogue common?) > > Yes, my typu, sorry. At the size of type used in the manual that came > with it, it takes a 16mm projection lens to magnify it enough to tell > the diff between a C and a G. Great printing job, but in 1 point type. > > > DCM is listed as digital common. > > And while it is not common, several megohms between them apparently > actually grounding them has no effect on its operation. But if ACM > isn't grounded to the 7i76 ground, then the analogin# have no ground > reference to measure AM(marked VO on my unit) from. So the reading is > zero most of the time and only a small floating point value when It > does flicker up a an occasional reading. I had to drag my sampling > scope up on the shelf, and probe the orange connector to discover > nothing on it is an actual ground. And in order to properly redo that > wiring I'll need to add some ground jumpers, at least one and to > segregate it right, move some signals from one cable to the other. > Might as well start all over. So I will.
Which I have now done, and rung it out with an ohmeter, but I haven't materially changed the results. I've got my scope hooked up to VO for realtime monitoring. ACM is truly grounded now. DCM is not but its all optical anyway. pd054=0 which is supposed to be an analog voltage from 0 to 10 volts, representing 0 to 400 hz from the invertor. But the output is actually a 10v p-p pwm corresponding to the duty cycle to get that % of a pwm. And I can't change it. And its got 3 volts of invertor noise sitting on it so my fawncy scope says about 16 volts p-p. Is there another register that overrides pd054's setting? I've re-read this book 3 or 4 times now without finding any clues... Or do I have a defective vfd? Thanks all. 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
