On Sunday 05 April 2020 04:37:25 andrew beck wrote: > Hey Gene. > > Just reading your reply here. > > So I have a 5i25 and 7i76 currently connected I'm running out of io,
I currently have 2 machines setup that way, but I also have a std bob on the 5i25's p2. the g0704's tally switches on the gear shift knob and something else that slips my ancient wet ram is also wired to that bob. > so am thinking of getting a 7i73 for the console buttons eg cycle > start so that I can free up my 7i76 io for the toolchanger. > > And I want to bring my encoder feedback from my Chinese step and > direction servos right back into linuxcnc. So need at least 3 more > encoder counters. The 7i90/7i42TA combo can do that. You'll need 3 of the 7i42TA's though, one for each 50 pin header on the 7i90. > > Also in the near future I will have a 4th axis on this VMC with a 5 > > axis trunion to follow soon after. But I can buy another card then > > if I need to. Though if it makes sense I can buy it now. All of > > these axis will need feedback right to the main control. (I'm sick > > of loosing position whenever I push in estop / turn off servo power > > to motor haha) And I'm fond of controlling machine power from the f1 or f2 buttons. Only takes one i/o unless there is 254 volts for the vfd. However 2 of those 40 amp $12 crydoms could be switched by one line. The inrush of the g0704 will clear a 25 amp circuit breaker so that takes 2 i/o's to soft start it, Stage one has a 50 ohm 200 watt R in series, which is shorted by the second SSR 3 seconds later. > On Sun, Apr 5, 2020, 8:11 PM Gene Heskett <ghesk...@shentel.net> wrote: > > On Sunday 05 April 2020 01:29:50 andrew beck wrote: > > > Hey guys. Just getting back to this while we all have some free > > > time. > > > > > > Todd could you please confirm what card you use for closing the > > > loop back to the control when using step and direction control? I > > > want the most encoders and general io I can get Ideally. Don't > > > need serial ports etc.. > > > > Depending on the firmware you put in it, the 7i90 can have 4 to 8 > > stepgens, and 4 pwm-gens, and 4 encoders. You can talk to it over > > spi, or you could use a 5i25. And it has a 3rd 16 bit wide and > > faster means if the parport is totally bi-dir. > > > > All its i/o, 72 pins worth, is a bit fragile, just barely tolerant > > of 5 volts and to be safe around a box full of stepper drivers, > > needs 3 7i42TA's for protection, but that also makes hookup a piece > > of cake by giving you the usual green screw terminals to wire it up. > > > > That is what I'm using to drive an 11x54 sheldon from a pi4, and > > I've still enough i/o left over to handle a 6 pole turret mount. > > > > > On Thu, Feb 13, 2020, 3:13 AM Todd Zuercher > > > <to...@pgrahamdunn.com> > > > > wrote: > > > > The machine I am using this on was already set up and running > > > > Linuxcnc, but only using software stepping (but not using a > > > > parallel port for the I/O). I was having a lot of trouble > > > > getting a good tune on the servos as well. At that time the > > > > 7i85S, was the only option for hardware step generation and > > > > encoder feedback. And since the machine was already set up and > > > > running Linuxcnc I didn't need to worry about hooking up other > > > > gpio. Unfortunately once the existing PC dies, I will probably > > > > have to buy something else for the gpio, because it is using a > > > > rather expensive ISA card for that. Not to mention the fact > > > > that I can't seem to get a real time os newer than our old > > > > Ubuntu 10.04 .ISO to run on that ISA/PCI slot motherboard. I'll > > > > probably just end up buying a 7i84 and scrap all of the old IO > > > > boards that go with that old ISA card, when that day comes. > > > > > > > > The 7i76 only has one encoder input and the 7i76e or any of the > > > > other Ethernet cards didn't exist yet (at that time). The 7i84 > > > > is a Smart Serial card and is only serviced at servo thread > > > > speeds, so it's only good for gpio with no encoder inputs (the > > > > two MPG inputs don't count because they aren't fast enough for > > > > servo use). I think the 7i84 is pretty much exactly the same as > > > > the built in GPIO on the 7i76. > > > > I've 2 of the mpja encoder dials, 100ppr style on the sheldons new > > front apron so I can drive it by hand. Rigged up in hal for jog > > sizes from .0001" to .020" per click on a 1-2-5 scale, which is fast > > enough to hit either axises speed limits. But all that runs in a > > 200hz thread, not in the servo thread. > > > > And I've still got gpio's, 30 or so that I haven't used. And if I > > survive the virus, thinking of converting the step/dir steppers to > > step/dir controlled 3 phase servo's. > > > > > > Todd Zuercher > > > > P. Graham Dunn Inc. > > > > 630 Henry Street > > > > Dalton, Ohio 44618 > > > > Phone: (330)828-2105ext. 2031 > > > > > > > > -----Original Message----- > > > > From: andrew beck <andrewbeck0...@gmail.com> > > > > Sent: Tuesday, February 11, 2020 7:30 PM > > > > To: Enhanced Machine Controller (EMC) > > > > <emc-users@lists.sourceforge.net> Subject: Re: [Emc-users] > > > > closing the loop in linuxcnc with a 7i76 mesa card and step > > > > direction control > > > > > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > > > > > Hey Todd. > > > > > > > > Was there a reason you went to a 7i85 rather than a 7i76 and > > > > 7i84? > > > > > > > > All I can think of is you didn't need the extra io of the 7i76. > > > > So could do it with only two cards. > > > > > > > > Regards > > > > > > > > Andrew > > > > > > > > On Wed, Feb 12, 2020, 3:11 AM Todd Zuercher > > > > <to...@pgrahamdunn.com> > > > > wrote: > > > > > I'm using a 5i25+7i85s to run a large gang router with > > > > > step/dir servos. This machine has a lot of mechanical warts > > > > > that have made getting a good tune on the servos difficult. > > > > > Having the encoder feedback made tuning a little easier, and > > > > > saves me from having to break out the o-scope to work on it. > > > > > > > > > > Todd Zuercher > > > > > P. Graham Dunn Inc. > > > > > 630 Henry Street > > > > > Dalton, Ohio 44618 > > > > > Phone: (330)828-2105ext. 2031 > > > > > > > > > > -----Original Message----- > > > > > From: andrew beck <andrewbeck0...@gmail.com> > > > > > Sent: Monday, February 10, 2020 7:11 PM > > > > > To: Enhanced Machine Controller (EMC) > > > > > <emc-users@lists.sourceforge.net> > > > > > Subject: Re: [Emc-users] closing the loop in linuxcnc with a > > > > > 7i76 mesa card and step direction control > > > > > > > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > > > > > > > Awesome Todd > > > > > > > > > > What Mesa card did you use? And do you mind if I pick your > > > > > brains on this rather than reinventing the wheel. I would > > > > > love to see a config that works so I can compare it with what > > > > > I have and make the needed > > > > > > > > changes. > > > > > > > > > Also did you find the motion was uneven or did it just work as > > > > > expected. > > > > > > > > > > Regards > > > > > > > > > > Andrew > > > > > > > > > > On Tue, Feb 11, 2020, 11:20 AM Todd Zuercher > > > > > <to...@pgrahamdunn.com> > > > > > > > > > > wrote: > > > > > > It works very much similar to running them with an analog > > > > > > input. The encoder feedback can also be handy for double > > > > > > checking the tuning of your servo drives. > > > > > > > > > > > > You simply disconnect the position feedback from the stepgen > > > > > > and use the feedback from the encoders to connect to the PID > > > > > > and the joint > > > > > > > > > > position-fb. > > > > > > > > > > > You will need to tune the feedback loop, P=1000 will no > > > > > > longer be valid, and will likely have to be significantly > > > > > > less (guess 1/2-2/3) > > > > > > > > > > > > Todd Zuercher > > > > > > P. Graham Dunn Inc. > > > > > > 630 Henry Street > > > > > > Dalton, Ohio 44618 > > > > > > Phone: (330)828-2105ext. 2031 > > > > > > > > > > > > -----Original Message----- > > > > > > From: andrew beck <andrewbeck0...@gmail.com> > > > > > > Sent: Monday, February 10, 2020 4:46 PM > > > > > > To: Enhanced Machine Controller (EMC) > > > > > > <emc-users@lists.sourceforge.net> > > > > > > Subject: Re: [Emc-users] closing the loop in linuxcnc with a > > > > > > 7i76 mesa card and step direction control > > > > > > > > > > > > [EXTERNAL EMAIL] Be sure links are safe. > > > > > > > > > > > > Actually all I want to do is be able to home to index. > > > > > > Which I might be able to do now. As my servo can output a > > > > > > encoder Z pulse. > > > > > > > > > > > > And I want to have linuxcnc remember where it is if I > > > > > > disable the > > > > > > > > servos. > > > > > > > > > > That is now a massive deal but I get a bit sick of > > > > > > continously homing the machine every time I push the E stop > > > > > > in and disable power to servos. It would be nice to have > > > > > > the encoders still counting once the servos are disabled. ( > > > > > > drives would still be on just not running a PID > > > > > > loop.) > > > > > > > > > > > > And yes I was wondering what trying to run a PID loop on a > > > > > > position servo loop causes. > > > > > > > > > > > > Regards > > > > > > > > > > > > Andrew > > > > > > > > > > > > On Tue, Feb 11, 2020, 2:14 AM andy pugh <bodge...@gmail.com> > > > > wrote: > > > > > > > On Mon, 10 Feb 2020 at 10:30, andrew beck > > > > > > > <andrewbeck0...@gmail.com> > > > > > > > > > > > > > > wrote: > > > > > > > > On the back burner though I want to > > > > > > > > > > > > > > "close the loop" back into linuxcnc with a 7i84 mesa card > > > > > > > I think. Has anyone done that before with a step direction > > > > > > > control system? > > > > > > > > > > > > > > What do you anticipate gaining from bringing the encoders > > > > > > > back to > > > > > > > > > > > > LinuxCNC? > > > > > > > > > > > > > If this is a stepper system (it's not clear without > > > > > > > inbox-mining) then a PID will naturally attempt to run the > > > > > > > motors faster, with the reverse of the hoped-for result. > > > > > > > It is probably possible to simultaneously reduce the feed > > > > > > > rate with adaptve feed and then attempt to recover the > > > > > > > lost steps, but I don't know if anyone has tried that. > > > > > > > > > > > > > > If it is a step-servo system then the drives will already > > > > > > > be doing all that they can. You won't gain much from > > > > > > > bringing the motor encoder data in to LinuxCNC. > > > > > > > However, you might be able to gain accuracy by adding > > > > > > > linear scales to the system, and using the feedback from > > > > > > > them to modify the motor position commands. > > > > 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 > > _______________________________________________ > 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
