Differential. Yes with the spindle. Installed 2 years ago and then tested learned that the US Digital Encoder wasn't adequate. Changed to CUI encoder. Problems went away. Repeatable and accurate motion. The Shumatech DRO-350 matched LCNC.
Only recently when doing this latest project has it suddenly started giving problems and they were repeatable with or without the spindle running. Now after unplugging and plugging in the CUI connector and putting everything back together is it working properly as it did originally. So I'm going to guess that there is an intermittent in the wiring in the connector that surfaces with vibration. Perhaps one of the differential connections opens up. That could explain why the errors only accumulate in one direction. Just guessing here. I expect it will happen again. I will make an extra adaptor cable. Don't want to replace randomly. That never really solves problems. Just hides them until some other time. John > -----Original Message----- > From: Sam Sokolik [mailto:samco...@gmail.com] > Sent: August-07-21 11:52 AM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Something went wrong. > > Are these running single ended? Have you tried it with the spindle > running? > > sam > > On Sat, Aug 7, 2021 at 11:33 AM John Dammeyer <jo...@autoartisans.com> > wrote: > > > Hi Jon, > > > From: Jon Elson [mailto:el...@pico-systems.com] > > > On 8/4/21 1:53 AM, John Dammeyer wrote: > > > > In fact, a bit more work just now shows that the X axis is losing > > position in the positive(?) direction. So on each return to X0 after a > > > bunch of jogging back and forth (even without backlash enabled) shows as > > high an error as -0.156". And it's cumulative increasing in > > > the negative count direction. > > > > > > > > That wasn't there when I first changed from the US Digital Encoders to > > the CUI encoders. So either the encoder is slipping on the > > > shaft or the way the wires are run is creating noise that changes the > > encoder values. > > > > > > > Yes, you have some sort of issue there.? The CUI encoders > > > have a plastic collet that has a clamp ring that has to be > > > snapped down quite forcefully to close the collet on the > > > shaft.? Sometimes the molding is not precise and the collet > > > doesn't grip well.? Some people put a drop of superglue on > > > the shaft to make sure it holds.? I hope you can find the issue. > > > > > > Jon > > > > I pulled the motor off the machine and then removed the encoder part. No > > matter how hard I tried I could not rotate the plastic collet that turns > > the encoder disk. On solid. No super glue needed here. > > > > Decided I'd put it back together and use the instructions Henrik Olsson > > gave me on interpreting the GP, GE and GT commands to his processor > > module. Figured I would see if the 150,000 encoder counts were occurring > > in a 10" move in both directions or if just in one. > > > > Wouldn't you know it. Works perfectly again. Doesn't matter how much > > jogging I do a 10" move in either direction from 0.000" to 10.000" reports > > as 150,000 encoder counts; as it should. Now once again the DRO-350 and > > LCNC agree. > > > > Since I didn't change anything I can only assume that perhaps the teensy > > tiny connector to the encoder has a poor crimp on one of the pins and the > > vibration over time caused an erratic connection. Pulling it out and > > putting it back in resulted in it (temporarily?) being properly connected > > and now things work again. > > > > I guess I'm going to have to wait until it once again screws up > > positioning while making something. Then only remove the encoder cap, > > unplug and plug in the tiny connector and see if the problem is fixed > > again. And I'm going to make up a second DB-15 to CUI connector for inside > > the end cap just in case it's intermittent that becomes permanent. > > > > John Dammeyer > > > > > > > > > > > > _______________________________________________ > > 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 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
