On Saturday, September 17, 2022 at 09:11:26 p.m. EDT, gene heskett <ghesk...@shentel.net> wrote: Greetings, got a new idea;
I am currently doing half the "make it round" part of my screw code without any taper comp. to correct for the axis z height diff from the driven end of the stick to the live center. Printing shims to put under the live center is limited in how close I can get that because of the printers z step height. So the best I can do there is to get it within that step height, measure it at both ends of the stick, which is diameter, and cut that in half cuz we're fixing it with a radius change. But that tiny a tool dulls and the flexibility of the x rods etc in the gantry means I can see the tool rising as the corners of the square stick go by. So far I've been fudging by making the correction larger, but as it approaches true round there is less and less motion because its always being pushed away by the dulling tool. So I got this wild idea of sampling a 5kg strain gauge to measure this deflection, and run an add of its reported error to push the tool back down, making the tool follow the programmed path a little closer. But to do that right, at least in my mind, I've got to sample the gauge as the peak of the original square goes by at 4x per full turn. Or maybe sample the peak regardless of its position. And rig a running average in my samples. Once per rev is easy enough, just use the B home signal as a trigger, but how would I rig a pll to do it 4x per turn? And make it immune to feed rate changes... A timer started by the home switch would determine the first sample point and an led banged by a cap shining on the stick would help to time the first sample of each turn, but its been decades since the last time I made a pll do as it was told. And I don't see a pll module in the hal menu. Ideas? Like how to make it keep a running average over 4 samples. I did do that on the go704, trying to make my low rez optical spindle encoder less noisy, but the real cure was an encoder on the motor, and tally switches on the gear shift knob to change the Scale... Take care & stay well everybody. 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, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/> Hello Gene. I would monitoring the state of the four corners as they turn.On my lathe, the spindle hole diameter, through the headstock of the lathe, is one and one eight of an inch.This pipe (or tube) through the headstock is driven by the lathe, and then the mounting point for what I am imagining is the the lathe dog driving the four sided wood.I would then mount a one part in 10 to the 14 rotational (chips + electronics + magnet) on the spindle hole pipe, to tell me where the wood is. Then comes the "where is the point I want to measure" and "how much distance do I put into the toolbit" programming work.If you want a kit of the stuff, I have two of them. If someone else has already provided that idea, I apologize.This is the first time in a couple months I have got back to reading the emails. James Isaac. _______________________________________________ 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