Would it make a difference which card I have my 7i84 connected to? I currently have it connected to the 7i85s. Would moving it over to the 7i88 be better?
Todd Zuercher P. Graham Dunn Inc. 630 Henry Street Dalton, Ohio 44618 Phone: (330)828-2105ext. 2031 -----Original Message----- From: Peter Wallace <p...@mesanet.com> Sent: Wednesday, July 17, 2024 3:00 PM To: Todd Zuercher via Emc-users <emc-users@lists.sourceforge.net> Cc: Todd Zuercher <to...@pgrahamdunn.com> Subject: Re: [Emc-users] 5v Encoder Power? [EXTERNAL EMAIL] Be sure links are safe. On Wed, 17 Jul 2024, Todd Zuercher via Emc-users wrote: > Date: Wed, 17 Jul 2024 16:59:54 +0000 > From: Todd Zuercher via Emc-users <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > Cc: Todd Zuercher <to...@pgrahamdunn.com> > Subject: [Emc-users] 5v Encoder Power? > > Working on my 8 head machine refitting. > > The machine had been previously configured using a Mesa 5i25+7i85s > doing closed loop step/dir control with encoder feedback of 3 servos(xyz). > (Other miscellaneous gpio was handled on an ISA card.) Power for the > Mesa 7i85s was through the cable via the 5i25. > > With the update, the ISA card was replaced by a Mesa 7i84, and 7 > additional step/dir outputs added using a Mesa 7i88. The new machine > configuration is using 2 of the old servos to control the either end > of the Y gantry (previously only 1 servo), and 8 closed loop steppers > have been added for each of 8 Z spindles. > > It appears that adding and powering the 7i88 from the 5i25 has put too > much load on the 5v supply from the 5i25. Now, when the servo drives > are not powered I am having trouble with the encoder feedback running > away. I don't think this was a problem previously. When the drives > are powered they add to the 5v that supplies the encoders and the feedback is > steady. Thats unexpected since the 7I88 should draw only a few 100 ma when fully loaded. Are you sure the 5I25 and 7I88 cable power jumpers match? > > My 1st question is how large of a 5v supply should I add to power the > 7i85s and the encoder feedback? Should I power both the 7i88 and > 7i85s using this supply or keep one powered from the 5i25? Would > powering from a USB port be sufficient? The 7I85S draws about 250 mA by itself, any encoder power needs to be added to this > > Next question while I setting up and trying to tune the gantry servos, > I found that I was having trouble with the position feedback from the > Mesa stepgen getting out of sync with the feedback from the encoders > if the drives were ever disabled. Then when I am trying to run closed > loop using the encoder feedback, if the drives are disabled, I have > trouble with joint following errors when re-enabling them. Any suggestions > for this problem? > I believe the problem is the gantry is going out of alignment when > shut down and there needs to be some provision for resyncing them when > they are re-enabled. But I'm not sure what steps need to be taken to do that. > Rehoming might be an option (but not what I'd prefer), but I can't > even turn the machine back on (F3) without closing and restarting Linuxcnc. > If you are running with encoder feedback, the stepgen position should not be used (the stepgens would be run in velocity mode and only encoder feedback used) > Todd Zuercher > P. Graham Dunn > Inc.<https://nam04.safelinks.protection.outlook.com/?url=http%3A%2F%2F > www.pgrahamdunn.com%2Findex.php&data=05%7C02%7Ctoddz%40pgrahamdunn.com > %7Cd03a680d4c574b7238b408dca692ba65%7C5758544c573f47cebee96c3e0806fb43 > %7C0%7C0%7C638568396327601119%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw > MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C0%7C%7C%7C&sdata= > Ab3OmM3kVfeS1343cihBJSCm5O2wo4%2FWhMikKz9PxIc%3D&reserved=0> > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Flist > s.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=05%7C02%7Ctoddz% > 40pgrahamdunn.com%7Cd03a680d4c574b7238b408dca692ba65%7C5758544c573f47c > ebee96c3e0806fb43%7C0%7C0%7C638568396327615172%7CUnknown%7CTWFpbGZsb3d > 8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C > 0%7C%7C%7C&sdata=5%2FUdsJKuwA7kWOSULohDAzqYZhOrvw246nQXwfUOo8s%3D&rese > rved=0 > Peter Wallace Mesa Electronics _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
