On Wednesday 28 September 2016 19:35:18 andy pugh wrote: > On 29 September 2016 at 00:03, Gene Heskett <ghesk...@shentel.net> wrote: > > > VFDs norrnally need their inputs pulled down to their own digital > > > GND. (Have you tied BoB GND to VFD GND?) > > > > No, I haven't yet. I have no clue whether the "power source ground" > > is in fact connected to the 3rd pin since for single-phase operation > > it is supposed to have terminals L & N, but they are missing, and > > when asked I was told to just use any 2 of R-S-T. > > That is _so_ not what I meant. > > The VFD will have a signal GND. Probably called DCM on a Huanyang
Trash night, lot of walking to collect it all and coerce it into two 13 gallon kitchen bags & walk them out to hang on the picket fence for the truck in the morning. So my legs need a 15 minute rest & I'll go see about it. I suspicion that the whole control interface, 7 lines in all including what they also call the 'common control signal" shown connected to the ground, is isolated. But I'll verify as it doesn't seem workable w/o it. I've let the magic smoke out of too much stuff by not verifying. Ok, checked now. No detectable continuity between powerline common ground, and the control circuit ground. And about .30nf capacitance between them. Plugged in and turned on, but no motor connected, the fwd and rev terminals are sittin at nominally 12.5 volts + from that isolated common control ground. Now I wonder what the outputs on this bob can stand? The waveforms I am seeing are hard switches, with zero resemblance to an open collector circuit. IOW, they will need a postage stamp with some opto's on it. And just when I thought I'd hit a lick... Opto's I think I have but I'll need to carve up a board & stick it someplace next to the bob. Time sinks... Tomorrow I have to take the toy to the dealer, a couple recalls are open, and the left rear caliper is freezeing on the mount bolts, probably ought to have both sides cleaned & lubed. No clue how much I'll get done tomorrow after that. Is that what you expected I would find? 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) 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
