Rick, I'm working on a Fanuc spindle that uses that same "encoder" (my motor is a Model 3 PN: A06B-1003-B100 at 3.7/5.5kW) on a Burgmaster Powerhawk VTC-150.
It's not actually an encoder but a magnetic pulse generator that reads the teeth on a gear on the top of the motor. It has six leads: +5V, 0V, PA, RA, PB, RB. +5V and 0V are obviously the power connections. PA is Pulse for phase A, it outputs a sine wave that goes from about 2.25V to 2.75V (can be less, the magnets in the read head lose strength over time and put out a weaker wave). PB is Pulse for phase-B, it is the same as PA but offset 1/4 of a wavelength (90 degree offset). RA and RB are Reference phase-A and Reference phase-B respectively. These put out a constant 2.5V signal. All of these signals tend to be pretty noisy. (Note that the two sine waves are centered at this same 2.5V.) I don't know if the Mesa card can read that sine wave, I'm pretty sure it's only meant to split digital square waves. As soon as these signals get back to the drive, they are run through a comparator circuit that compares the sine waves to their reference voltages and puts out 0-5V square waves. (Why they don't do this in the encoder is beyond me, I just chalk it up to the weird things Fanuc does.) Assuming you are still using the Fanuc spindle drive, you could skip using the ENCY card and feed the "encoder" straight back to the drive. There should be two test points on the drive where you can tap into the square wave signals after the drive has converted the sine waves. On my drive these two points are CH7 and CH8 and they are conveniently located right next to a 0V test point. I have a PDF copy of the maintenance manual for this drive, if you want a copy. I ditched the Fanuc drive on my machine (for reasons unrelated to the encoder) and replaced it with a Hitachi WJ200 VFD that doesn't need an encoder. I'll be building my own simple comparator circuit to convert the signal to feed into a 7i77. Also, to answer your initial question, the gear that the pulse generator reads has 250 teeth. Once converted to quadrature signals, you get 1000 pulses per revolution. -Chris K. On Fri, May 22, 2015 at 12:57 PM, <[email protected]> wrote: > Thread mill? Easy to have exact thread orientation that way. > > > ------Original Mail------ > From: "Bruce Layne" <[email protected]> > To: "Enhanced Machine Controller (EMC)" <[email protected]> > Sent: Fri, 22 May 2015 13:27:40 -0400 > Subject: Re: [Emc-users] Fanuc Spindle Motor Encoder PPR > > Hey Chris, > > Nice video! Nice LinuxCNC VMC! > > I noticed that your spindle is indexed randomly at the start and end of > each rigid tapping cycle. This verifies Andy's assertion that LinuxCNC > only uses the index pulse to initiate rigid tapping and uses the other > spindle encoder signals exclusively to match the Z travel to the spindle > rotation. That works great for a fixture plate, but I'll be making > parts where I need the threads to be indexed relative to the part > geometry. In other words, I need all of the parts to screw on to mating > parts and radially align in approximately the same position each time. > That's seldom the case, but it is for me. That's why I need the spindle > encoder on the spindle. > > As long as we understand the limitations, all is well. To a large > extent, that's the difference between doing a LinuxCNC conversion > yourself and using a more plug-and-play solution. It's like the > difference between being a programmer/hacker as opposed to someone who > uses a PC to update their Facebook status. > > Back on topic.... If I was Rick, I'd find SOME way to put an encoder on > the spindle, even a low resolution encoder, and avoid patching LinuxCNC > on the software side. I like to upgrade LinuxCNC when all of the great > new features are added, and I don't like spending time to patch it each > time to get it running again for my specific machine. I try to keep the > machine as generic as possible, but that strategy flies in the face of > fun projects like home brewed tool changers and other stuff I want to > do. The best I can do is TRY to keep it simple. > > > Bruce > > > > > > > On 05/22/2015 11:37 AM, Chris Radek wrote: > > On Fri, May 22, 2015 at 01:32:23PM +0100, andy pugh wrote: > >> I believe that the cycle uses the index at most once per in-out move, > >> so as long as you are not peck-tapping it will still work. > > On my vmc, there is an untoothed belt drive between the spindle and > > motor. The spindle encoder is on the motor. The encoder does not > > have index. I don't know what the belt ratio is, exactly. I scaled > > it by measuring, and jumpered A to Z on the mesa's input. So, it > > gets indexes everywhere. > > > > Tapping works great. > > > > https://www.youtube.com/watch?v=9HLKXeWqTF0 > > > > I have never wanted to peck tap by cnc. > > > > > ------------------------------------------------------------------------------ > > One dashboard for servers and applications across Physical-Virtual-Cloud > > Widest out-of-the-box monitoring support with 50+ applications > > Performance metrics, stats and reports that give you Actionable Insights > > Deep dive visibility with transaction tracing using APM Insight. > > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > > _______________________________________________ > > Emc-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
