thanks Todd. sounds like I should get the 7i85s then. or possibly the 7i89 if I can get a hold of them. as peter said above that they have extra encoder counters which would be nice for a future 5 axis project.
I am just trying to get the chinese servo tuning software going now actually. they are helping me by We chat. the language barrier is a bit of a pain but there english is not bad and they are definitely keep to help me. regards Andrew On Mon, Apr 6, 2020 at 5:26 PM Todd Zuercher <[email protected]> wrote: > I am only using the Mesa card for Step/dir and the encoder feedback. The > rest of the digital IO is still using the old hardware. Have a 5i25+7i85S, > spindle VFDs are modbus, and digital io is via an old Adlink ISA card. > > Todd Zuercher > P. Graham Dunn Inc. > 630 Henry Street > Dalton, Ohio 44618 > Phone: (330)828-2105ext. 2031 > > -----Original Message----- > From: andrew beck <[email protected]> > Sent: Sunday, April 05, 2020 1:30 AM > To: Enhanced Machine Controller (EMC) <[email protected]> > 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 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.. > > On Thu, Feb 13, 2020, 3:13 AM Todd Zuercher <[email protected]> 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. > > > > Todd Zuercher > > P. Graham Dunn Inc. > > 630 Henry Street > > Dalton, Ohio 44618 > > Phone: (330)828-2105ext. 2031 > > > > -----Original Message----- > > From: andrew beck <[email protected]> > > Sent: Tuesday, February 11, 2020 7:30 PM > > To: Enhanced Machine Controller (EMC) > > <[email protected]> > > 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 <[email protected]> > 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 <[email protected]> > > > Sent: Monday, February 10, 2020 7:11 PM > > > To: Enhanced Machine Controller (EMC) > > > <[email protected]> > > > 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 <[email protected]> > > > 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 <[email protected]> > > > > Sent: Monday, February 10, 2020 4:46 PM > > > > To: Enhanced Machine Controller (EMC) > > > > <[email protected]> > > > > 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 <[email protected]> wrote: > > > > > > > > > On Mon, 10 Feb 2020 at 10:30, andrew beck > > > > > <[email protected]> > > > > > 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. > > > > > > > > > > -- > > > > > atp > > > > > "A motorcycle is a bicycle with a pandemonium attachment and is > > > > > designed for the especial use of mechanical geniuses, daredevils > > > > > and > > > > lunatics." > > > > > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > > > > > > > > _______________________________________________ > > > > > Emc-users mailing list > > > > > [email protected] > > > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > > > > > _______________________________________________ > > > > Emc-users mailing list > > > > [email protected] > > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > _______________________________________________ > > > > Emc-users mailing list > > > > [email protected] > > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > > _______________________________________________ > > > Emc-users mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > _______________________________________________ > > > Emc-users mailing list > > > [email protected] > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
