problem pitch theards lathe

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26 Feb 2013 17:32 #30606 by andypugh
Another though. It might not be the spindle encoder. Are Z moves exactly correct?

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26 Feb 2013 21:46 - 26 Feb 2013 21:50 #30610 by jlviloria
Andy, Filipe thanks,


I have the following values:

1rev/hand

Encoder.05.counts = 4089 ---- 4095
Enconder.05.positions= 3.992188 ---- 3.998047

when I come back I mark the position:

Encoder.05.counts = -2 --- 2
Enconder.05.positions= 0.002929688 ---- 0.003048981

i have encoder: BEI AUTOMATION H25E-SS-1024-ABZC-8830-LED-SM18-S

My .INI have:

encoder scale= 1024

Z for my moves correctly, has a max error 20um

One thing I should say is that this machine has low-gear and high gear. but now only use low-gear. I have not been configured to work with me M141 And M142, in I'm still processing. not if it has something to do also.


thanks
Last edit: 26 Feb 2013 21:50 by jlviloria.

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26 Feb 2013 22:02 #30612 by emcPT
Replied by emcPT on topic problem pitch theards lathe
It looks ok to me, but Andy knows a lot more. Maybe he can give his opinion.
Can you post your HAL file?

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26 Feb 2013 22:31 #30615 by andypugh

1rev/hand
Encoder.05.counts = 4089 ---- 4095
Enconder.05.positions= 3.992188 ---- 3.998047

encoder scale= 1024


It looks to me like the SCALE in the INI needs to be 4096

It is very common for encoders to count 4x as fast as expected as there are 4x as many quadrature transitions as there are encoder slots.

You would normally expect that the result would be 4x the expected screw pitch. I suspect that you don't see that because the Z-axis isn't fast enough, so you are seeing a random pitch.
(A simple test would be to make a new part at half the spindle speed, I think you would see twice the pitch).
The following user(s) said Thank You: jlviloria

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26 Feb 2013 22:57 #30617 by jlviloria
andy, you put 4096. and made the perfect thread.

the only thing I feel strange is that speedometer tells me a little more speed,

if I schedule indicated speed 200rpm at.speed tells me 350 rpm. but the thread does well. :)

speedometer is the of linuxcnc. no physical

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