Re: [Emc-users] 60's vintage position feedback.. (GE Accupins)
On Tue, Jan 25, 2022 at 6:37 PM John Dammeyer wrote: > > So how exactly are you going to count it?Time between the top trace > edge and the bottom trace edge? As you cross the threshold into the next > 0.1" and it mechanically jitters at that point what will you do to not have > counts go wild? > I would guess that something similar to a switch debounce would be used. This can be implemented in software.One simple algorithm is to sample the voltage and wait until you get let's say 5 identical readings. There are other tricks like low pass filtering. But the "N identical" method is easy to do and works well. -- Chris Albertson Redondo Beach, California ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] 60's vintage position feedback.. (GE Accupins)
Very cool Sam. It looks like the pin rail may be reproducible, but do you have any idea what the coil pickup structure is? Probably 3 coils... excitation, and the 2 quadrature phase or possibly many coils on a 1." spacing. The concept is very interesting if we could reproduce sensors like this at a reasonable cost. A similar product was call inductosyn I believe. https://www.maccon.com/rotary-linear-encoders/magnetic-encoders/inductosyn.html http://what-when-how.com/electric-motors/linear-and-rotary-inductosyns-electric-motors/ I have seen a similar sensor that used ball bearings in a tube. http://www.newall.com/technology/ this seems to show a good cutaway view. One idea I had was to try and use a ground ball screw as the sensor rail with magnetic pickups on several of the threads. Thus the rod providing the positioning would also provide position feedback of the nut (sensor coils ride on the nut). A slightly different idea (and probably less precise) is to use a rack as the sensor. With optical encoders being so cheap these days, its probably just an academic interest, but any ideas you have on the pickup coil design would be very interesting. cheers Lawrence VE7IT Nanoose Bay BC, Canada ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] 60's vintage position feedback.. (GE Accupins)
Hi Sam, So how exactly are you going to count it?Time between the top trace edge and the bottom trace edge? As you cross the threshold into the next 0.1" and it mechanically jitters at that point what will you do to not have counts go wild? John > -Original Message- > From: Sam Sokolik [mailto:samco...@gmail.com] > Sent: January-25-22 6:19 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] 60's vintage position feedback.. (GE Accupins) > > https://youtu.be/7HtqwcKDlCk > > On Sun, Jan 23, 2022, 6:47 PM Chris Albertson > wrote: > > > This > > > > On Sun, Jan 23, 2022 at 4:30 PM andy pugh wrote: > > > > > On Sat, 22 Jan 2022 at 04:49, Chris Albertson > > > > > wrote: > > > > > > > > Arduino? Too slow to coune pulses if they happen every 0.0001 inch > > > unless > > > > the table moves slow. > > > > > > As long as it gets a couple of samples every 0.1" it should be fine. > > > Between the pins it's an absolute encoder, like a multi-turn resolver. > > > > > > Though I would still suggest using one of the M4 or M0 boards from > > > Adafruit, as the clock rate and floating point performance are just > > > orders of magnitude higher, for about twice the cost. > > > > > > > That is about what I suggested. "Pico" is a dual core M0. Adafruit has them > > for $4 each. > > https://www.adafruit.com/product/4864 > > So yes, orders of magnitude better but half, not twice the cost. > > > > The price is so low that it is little different from free. That for two > > M0 cores at 125 MHz and 8 of those programmable state machine, also at > > 125MHz. and 2 MB of flash. Very good documentation. > > > > Works with Arduino IDE and runs most Arduio code but you can program it > > with Python too. > > > > > > > > > > > -- > > > 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 > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > > > ___ > > 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
Re: [Emc-users] 60's vintage position feedback.. (GE Accupins)
https://youtu.be/7HtqwcKDlCk On Sun, Jan 23, 2022, 6:47 PM Chris Albertson wrote: > This > > On Sun, Jan 23, 2022 at 4:30 PM andy pugh wrote: > > > On Sat, 22 Jan 2022 at 04:49, Chris Albertson > > > wrote: > > > > > > Arduino? Too slow to coune pulses if they happen every 0.0001 inch > > unless > > > the table moves slow. > > > > As long as it gets a couple of samples every 0.1" it should be fine. > > Between the pins it's an absolute encoder, like a multi-turn resolver. > > > > Though I would still suggest using one of the M4 or M0 boards from > > Adafruit, as the clock rate and floating point performance are just > > orders of magnitude higher, for about twice the cost. > > > > That is about what I suggested. "Pico" is a dual core M0. Adafruit has them > for $4 each. > https://www.adafruit.com/product/4864 > So yes, orders of magnitude better but half, not twice the cost. > > The price is so low that it is little different from free. That for two > M0 cores at 125 MHz and 8 of those programmable state machine, also at > 125MHz. and 2 MB of flash. Very good documentation. > > Works with Arduino IDE and runs most Arduio code but you can program it > with Python too. > > > > > > -- > > 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 > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > -- > > Chris Albertson > Redondo Beach, California > > ___ > 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] Freecad
Hey guys check this out Free cad is getting way better https://youtu.be/U9630DAmOA0 ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
