Hi folks. Many, many moons ago I got a degree in control theory. Closed loop control is the best way to implement CNC. It's more expensive than going the stepper motor route due to the cost of the scales but correctly set up will give far superior results. The need for the scale and read head installation to be firmly connected to the machine parts is perhaps the most critically important mechanical aspect. The theory of how to create a stable feedback control system has been known for many, many decades - I studied it back in the early 1970's. It's mainly down to setting the appropriate level of system gain, simpler in practice than in theory! Back in my day the 'computing' was done by analog means - yes, there were, and still are, analog computers. Gain was set by twisting a knob. Now of course it is nearly all digital. For far more detailed info lookup 'Nyquist stability criteria'.
No, whenever the scale reads a position deviation, the axismotor will correct this. But the backlash should be as small as possible, scales are not a fix for worn out rack and pinions...
Esa idea la tengo planteada hace un tiempo y en breve la llevaré a la práctica. Mi planteamiento es incorporar las señal de la regla al driver del motor de pasos o servodriver directamente
Did it work out of the box or they had to spend much of a time to tune the PID and encoder error flow calibration as we see in linuxcnc ? Any limitation on how much is the backlash to keep such feedback working accurate?.
Tunning is done in a minute with Centroid, any backlash over 0.04mm will cause problems while cutting, but no problem to compensate even more with a scale
Hast du das auch schon mit der C Achse probiert? Also Spindel drehen lassen dann C anschalten Ref fahrt und Full Closed Loop....und wieder zurück? Oder gibt es da Probleme? Gruss Stephan
mit der Messstab auf X hat die C-Achse ja nix am Hut, aber klar kann ich die ein und ausschalten nach belieben. Muss Dir mal das neue Makro für C senden....
@@TheSuntravel Danke dir. Also kannst du den Encoder nutzen für das Position Feedback? Das ja cool. Hab heute mein Acorn geschrottet. Bin schwer am knobeln wegen dem Six er Mhhhhh
this is awesome I was always wondering how ya could add scales. you lathe is coming along nicely, currently mine is frustrating me because needs more spindle motor power.
Hello, I've been wanting to buy an acorn for some time, but I always stay in mmm. My question is with the linear scale, can you remove the play from the nut, which centroid adjusts the distance, while machining or is it just to have a visualization of where it is?
Yes this is how closed loop works, it is permanently reading the scale position and correcting it to the programmed position. So it takes also care of the play in the nut.
@@TheSuntravel excellent, now with this I have no pretext to be able to buy it, another question, I saw that you talked about the macros, you need to make a macro or the software itself will help you, for a few weeks now I am your faithful follower
@@maq-Yantek For scales you need no macros. Some like for homing are generated by the Wizard, othere have to be written by hand, it is only g-code. All my stuff can be downloaded in the Centroid forum.
Super Mir war klar das es geht seit dem Ich mit G76 am Encoder gedreht habe. Danke für das zeigen. Musst du beim einschalten Ref fahren? Oder weiß Centroid direkt wo es ist? Gruss Stephan Mehr Eingänge wären gut Hihi
@@TheSuntravel Ist schon geiles Ubgrade.Vor allem hast die Präzision jetzt über den ganzen Weg.Zum neidisch werden.Ich muss mit der Werkzeug Tabelle rumspielen bis es passt. Ach um auf deinem Eintrag im Forum zu antworten. Würde ich um Hilfe bitten wenn ich mir selbst ein Macro basteln könnte? Gruss Stephan
Very nice, getting closed loop working with linear scale is a game changer for precision turning.
Hi folks. Many, many moons ago I got a degree in control theory. Closed loop control is the best way to implement CNC. It's more expensive than going the stepper motor route due to the cost of the scales but correctly set up will give far superior results. The need for the scale and read head installation to be firmly connected to the machine parts is perhaps the most critically important mechanical aspect. The theory of how to create a stable feedback control system has been known for many, many decades - I studied it back in the early 1970's. It's mainly down to setting the appropriate level of system gain, simpler in practice than in theory! Back in my day the 'computing' was done by analog means - yes, there were, and still are, analog computers. Gain was set by twisting a knob. Now of course it is nearly all digital. For far more detailed info lookup 'Nyquist stability criteria'.
Wait. So you can compensate for backlash in rack and pinnion by using a scale. And you don't need dual motors or dual pinions for it?
No, whenever the scale reads a position deviation, the axismotor will correct this. But the backlash should be as small as possible, scales are not a fix for worn out rack and pinions...
Esa idea la tengo planteada hace un tiempo y en breve la llevaré a la práctica. Mi planteamiento es incorporar las señal de la regla al driver del motor de pasos o servodriver directamente
Did it work out of the box or they had to spend much of a time to tune the PID and encoder error flow calibration as we see in linuxcnc ? Any limitation on how much is the backlash to keep such feedback working accurate?.
Tunning is done in a minute with Centroid, any backlash over 0.04mm will cause problems while cutting, but no problem to compensate even more with a scale
@@TheSuntravel Thank you for your reply, what type of servo motor and driver if used and the resolution of the encoder?. Am interested in your setup.
@@Transmission4less JMC 400W for axis and 1500W for spindle, all with 17bit encoder set to 10000 pulse/rev
@@TheSuntravel Thank you
Hast du das auch schon mit der C Achse probiert?
Also Spindel drehen lassen dann C anschalten Ref fahrt und Full Closed Loop....und wieder zurück?
Oder gibt es da Probleme?
Gruss Stephan
mit der Messstab auf X hat die C-Achse ja nix am Hut, aber klar kann ich die ein und ausschalten nach belieben. Muss Dir mal das neue Makro für C senden....
@@TheSuntravel Danke dir.
Also kannst du den Encoder nutzen für das Position Feedback?
Das ja cool.
Hab heute mein Acorn geschrottet.
Bin schwer am knobeln wegen dem Six er
Mhhhhh
Excellent stuff! DId you spot that Centroid have a board in the works allowing six additional scales/encoders/MPGs?!😊
yep, should be available in summer.
Very impressive work for small
Machines.
What cnc Machines do you have
this is awesome I was always wondering how ya could add scales. you lathe is coming along nicely, currently mine is frustrating me because needs more spindle motor power.
Hello, I've been wanting to buy an acorn for some time, but I always stay in mmm.
My question is with the linear scale, can you remove the play from the nut, which centroid adjusts the distance, while machining or is it just to have a visualization of where it is?
Yes this is how closed loop works, it is permanently reading the scale position and correcting it to the programmed position. So it takes also care of the play in the nut.
@@TheSuntravel excellent, now with this I have no pretext to be able to buy it, another question, I saw that you talked about the macros, you need to make a macro or the software itself will help you, for a few weeks now I am your faithful follower
@@maq-Yantek For scales you need no macros. Some like for homing are generated by the Wizard, othere have to be written by hand, it is only g-code. All my stuff can be downloaded in the Centroid forum.
How accurate is that probe You are using to touch off You tools?
If fresh dialed in and in the same orientation (probe and chuck), 0,01mm. But do not expect it to stay as long centered as Centroid probes.
@@TheSuntravel understand💪🏼
That's awesome! Great work!
Which type of servo motor are you using for the main spindle?
JMC 1.5kw Servo
What's the total cost for converting this lathe?
I did not collect every bill, better to not know the exact costs 🤣
That is pretty awesome!
Super
Mir war klar das es geht seit dem Ich mit G76 am Encoder gedreht habe. Danke für das zeigen.
Musst du beim einschalten Ref fahren?
Oder weiß Centroid direkt wo es ist?
Gruss Stephan
Mehr Eingänge wären gut
Hihi
Ist ja kein absoluter Messstab, also muss man referenzieren.
@@TheSuntravel Ist schon geiles Ubgrade.Vor allem hast die Präzision jetzt über den ganzen Weg.Zum neidisch werden.Ich muss mit der Werkzeug Tabelle rumspielen bis es passt.
Ach um auf deinem Eintrag im Forum zu antworten.
Würde ich um Hilfe bitten wenn ich mir selbst ein Macro basteln könnte?
Gruss Stephan
Am I going crazy? isnt that a 0.01 mm micrometer? as in 10 um
yes it is, but easy to eyeball about 2µ with them.
inpresive :)
Cool Videos Uwe! You need to talk more though. :)
No Problem, next video I will talk twice as much 🤣
Need some tight hardware so the machine doesn't oscillate.