Spindle motor to servo

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Re: Spindle motor to servo

Postby ThreeDJ16 » Thu Aug 30, 2018 8:17 pm

Robertspark wrote:And you're on the dark side with a centroid Acorn..... :lol: :mrgreen:

Crap....nobody was supposed to notice that part.

But in my defense, it's only because UCCNC doesn't offer full turning software. Otherwise it would be UCCNC all the way. As I love my UC300ETH/UCCNC/Screenset 2017. To be honest, Acorn and CNC12 is a royal PITA to setup, limited I/O and I just digress from there.
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Re: Spindle motor to servo

Postby Robertspark » Thu Aug 30, 2018 8:27 pm

ThreeDJ16 wrote: To be honest, Acorn and CNC12 is a royal PITA to setup, limited I/O and I just digress from there.


Now that is nice to know as I was thinking about that at one point {it was a brief thought though}. At the moment the plan is (its wired up) to run a UC400ETH with UCCNC and a Pokeys 57E for Mach4 (I have a licence already). Hence I could then run Mach3 with the UC400eth too if I really wanted / needed to. I have covered my bases on motion controller options.

I live in hope of a uccnc turn application (I know Balazs before you pipe up that there is no development plans for it in the near future.... we've been through that one a few times :roll: :roll: :D )
Rob
Einstein ― “If you can't explain it to a six year old, you don't understand it yourself”
...working my way through the 1000+ ways things don't work to find the one that does
UC400eth, UC300eth, UCCNC v1.2106, Neuron Lite
UCCNC v1.2105 Macro Manual
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Re: Spindle motor to servo

Postby ThreeDJ16 » Thu Aug 30, 2018 8:57 pm

Robertspark wrote:
ThreeDJ16 wrote: To be honest, Acorn and CNC12 is a royal PITA to setup, limited I/O and I just digress from there.


Now that is nice to know as I was thinking about that at one point {it was a brief thought though}. At the moment the plan is (its wired up) to run a UC400ETH with UCCNC and a Pokeys 57E for Mach4 (I have a licence already). Hence I could then run Mach3 with the UC400eth too if I really wanted / needed to. I have covered my bases on motion controller options.

I live in hope of a uccnc turn application (I know Balazs before you pipe up that there is no development plans for it in the near future.... we've been through that one a few times :roll: :roll: :D )

If you are someone that runs a FANUC machine everyday and wanted that at home, I suppose it would be familiar to you. But it's very different from most hobby software. My gripe was the PLC programming was total crap and it cost me another 200 bucks to get them to fix their own crap.....argh.....I was gonna stop on the last post....oh well.

Anyway, back to a subject brought up earlier about using the DYN 4 encoder pass through for UCCNC. I've been emailing back and forth all day with DMM tech support....nice and helpful folks. There is a scaling feature within their programming software which will allow you to scale down the PPR to a number in which your motion control card can handle. My C11G from CNC4PC is rated to 4mHz. I'm still too brain fried from all the pulley posts to think what the max PPR can be at 5K RPM and not saturate 4Mhz, but the point is that means I can use the A/B portion of the quadrature encoder in the DYN4 without the need of any divider circuits by adjusting the scaling. The sent me a nice diagram of how to use the DYN4 in 0-10v mode and have a forward reverse pin too or still just just step/direction. I didn't upload it immediately because the diagram is for hooking to a .........LOL....Acorn board. Hey, I can't help what they sent. I told them UCCNC and a UC300ETH/M45/C11G board, but they stated this was the closest they could do for me. Really this isn't a stretch other than the fact the C11G nor G540 (both in my system) either supply 0-10, so an additional 12v power supply would be needed in the circuit. And I'd use 5v versus their 24v for forward/ reverse, so the 2k resistor can get tossed. Now to get off my butt and get this R8 installed so I can move on to this new spindle motor.

-Jasen
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Re: Spindle motor to servo

Postby spumco » Fri Aug 31, 2018 1:39 am

FYI - earlier post about rigid tapping or lathe threading...

If you run anything other than 1:1 motor to spindle ratio - however you get there (gears/belts) - you'll just need an index trigger directly on the spindle. No need for a full-blown encoder, just a trigger. I'm using an NPN proxy with a set screw in an aluminum collar to trigger the spindle index.

My motor encoder is behind a 1:1.5 belt ratio. I have no spindle encoder. The pulley ratios are set up in UCCNC, and since a few updates ago UCCNC can do the encoder math so that commanded spindle speed results in accurate actual speed. No problems peck tapping at 1kRPM with a 100ppr (400-count) encoder. My encoder is low res because of my VFD's input limitations.

So for you two guys (Robert & ThreeDJ) who are working on a servo upgrade with the DMM's, here's my back-of-napkin thoughts:

1. Whatever belt/gear ratio you want. Me, I'd shoot for 3kRPM spindle speed if your bearings can handle it.
2. Drive programmed with electronic gearing so that encoder input/output doesn't overload your BOB's optos. You guys can do that math, but I'm pretty sure with decent optos you won't get a really coarse increment.
3. Use step-direction input and velocity mode. No need to fiddle with 0-10v.
4. Install spindle index trigger on outboard end of spindle. At 1kRPM max threading speed that's 60kHz. Just make sure the proxy (or whatever you use) can switch that fast.
5. Send the index signal to a BOB pin, and program UCCNC for the spindle index signal. Leave the DYN4 Z+/- output signal floating.

-Ralph
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Re: Spindle motor to servo

Postby ThreeDJ16 » Fri Aug 31, 2018 1:46 am

spumco wrote:FYI - earlier post about rigid tapping or lathe threading...

If you run anything other than 1:1 motor to spindle ratio - however you get there (gears/belts) - you'll just need an index trigger directly on the spindle. No need for a full-blown encoder, just a trigger. I'm using an NPN proxy with a set screw in an aluminum collar to trigger the spindle index.

My motor encoder is behind a 1:1.5 belt ratio. I have no spindle encoder. The pulley ratios are set up in UCCNC, and since a few updates ago UCCNC can do the encoder math so that commanded spindle speed results in accurate actual speed. No problems peck tapping at 1kRPM with a 100ppr (400-count) encoder. My encoder is low res because of my VFD's input limitations.

So for you two guys (Robert & ThreeDJ) who are working on a servo upgrade with the DMM's, here's my back-of-napkin thoughts:

1. Whatever belt/gear ratio you want. Me, I'd shoot for 3kRPM spindle speed if your bearings can handle it.
2. Drive programmed with electronic gearing so that encoder input/output doesn't overload your BOB's optos. You guys can do that math, but I'm pretty sure with decent optos you won't get a really coarse increment.
3. Use step-direction input and velocity mode. No need to fiddle with 0-10v.
4. Install spindle index trigger on outboard end of spindle. At 1kRPM max threading speed that's 60kHz. Just make sure the proxy (or whatever you use) can switch that fast.
5. Send the index signal to a BOB pin, and program UCCNC for the spindle index signal. Leave the DYN4 Z+/- output signal floating.

-Ralph


I'm curious on the why? UCCNC has an index pre-scaler, so why can't you just change that to match your ratio? I'm doing 1 to 2 (5k to 10K) so set the index prescaler to 2 since the motor will turn one turn for every two turns of the spindle. Or am I missing something here? Also, I thought for rigid tapping, the index pulse was not used, only the A-B signal was used? At least I remember reading that on a previous post from CNCDrive (sorry, I can't ever spell his name...LOL...sorry).

-=Jasen
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Re: Spindle motor to servo

Postby spumco » Fri Aug 31, 2018 2:08 am

UCCNC doesn't need an index signal to control the spindle speed, but it has to have an index signal to start the synchronized movement.

You can use the motor drive index signal as the initiating trigger, but UCCNC doesn't do the math for the trigger.

If you had a 1:2 ratio (or some other whole number) you might be able to 'trick' UCCNC and tell it you have 2 index signals per spindle revolution.

In your case you'll get one index signal per 2 revolutions of the spindle (5k motor, 10k spindle). Might still work out for you.

Me, not so much if I want to peck tap - the spindle will always be off by some oddball amount at each index signal since I have a 1:1.56 ratio (5400 motor/8400 spindle).
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Re: Spindle motor to servo

Postby Robertspark » Fri Aug 31, 2018 6:02 am

Thanks Ralph,

My spindle has an optical sensor disk on it, the inner shape is the index trigger .
It uses Optek OPB704 Photoelectric Sensors

I was going to use a round number on pulleys so that the encoder output with electronic gearing is accurate
Attachments
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Rob
Einstein ― “If you can't explain it to a six year old, you don't understand it yourself”
...working my way through the 1000+ ways things don't work to find the one that does
UC400eth, UC300eth, UCCNC v1.2106, Neuron Lite
UCCNC v1.2105 Macro Manual
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Re: Spindle motor to servo

Postby spumco » Fri Aug 31, 2018 10:28 am

Robert-

That's just cheating. You're supposed to cobble something up that maybe works on the 3rd try. :D
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Re: Spindle motor to servo

Postby ThreeDJ16 » Fri Aug 31, 2018 4:11 pm

The Emco PC 55 also came with a dual optical sensor plate on the spindle, but apparently the particular route I went requires at least 2000PPR quadrature signal. So had to pull all that off....LOL...and cobble something together, but it worked on the second try... :D
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Re: Spindle motor to servo

Postby ThreeDJ16 » Fri Aug 31, 2018 4:29 pm

Vmax549 wrote:You could turn that plate into an encoder by adding a second sensor offset from teh first. then you would have A B I signals same as an encoder.

Also you can also add an encoder driven by teh motor shaft just gear the belt drive so it turns 1:1 with teh spindle.

Just a thought, (;-) TP

The board in use on my lathe requires the 2k PPR, the plate only has 100 holes. What I have works, pics above, just looks like hell...LOL. One day I'll rebuild it from aluminum, but for now PETG works pretty freakn good..LOL.
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