Spindle and encoder

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13 Aug 2023 23:03 #277885 by rodw
Replied by rodw on topic Spindle and encoder

Rod, he did.


Spindle-off, manually rotate the pulley until the line intersects the channel and is lit.
-ve, Ground
+ve, 12.95VDC power supply
Output Signal Z 9.5VDC
Output Signal B 9.49VDC
Output Signal A 9.52VDC


 

Am I missing something because the halscope looks to be a high of 1 volt and from above it should be 9.5 volt? If its 1 v that may explain why its not right according to PCW.
The following user(s) said Thank You: tommylight

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13 Aug 2023 23:38 #277889 by smplc
Replied by smplc on topic Spindle and encoder
I reset the spacing of the encoder but it might not be any different than last time. All three LED's require to rest equally against the spacer and code wheel. It appears my images of this string cover most of the PncConfig setup on my behalf. Please inform me if any of the images could require adjusting the configuration and any editing with the .hal and .ini files. I could probably adjust the speed controller acceleration dial to match the commanded RPM to the tachometer reading. However, still, the shuffling numbers at the Hal Meter pin hm2_7i96s.0.encoder.00.velocity-rpm and the GUI and Hal Show pins hm2_7i96s.0.encoder.00.input-a and hm2_7i96s.0.encoder.00.input-b not quite 90 degrees out of phase. Would a prescale stop the shuffle numbers? Do the .hal or .ini files use a prescaler with an encoder? For instance, set the prescale 4 and encoder 10. 4 * 10 = 40 CPR.

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14 Aug 2023 00:28 #277894 by PCW
Replied by PCW on topic Spindle and encoder
Can you get decent looking quadrature signals in halscope?

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14 Aug 2023 00:34 #277895 by smplc
Replied by smplc on topic Spindle and encoder
Motor 6100 RPM max. The pulleys to the spindle have a speed reduction of approximately 46%. Adjusting the speed controller dial probably should be near the maximum acceleration which is 2800 RPM, however, matches the pulley ratio. I'm considering LinuxCNC_Documentation.pdf 12.2, using and editing some code if not already and if applicable.

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14 Aug 2023 00:40 #277896 by smplc
Replied by smplc on topic Spindle and encoder
Yes, somewhat. About as decent as it is, is from the last image in this string. I tried other times after and the analog signal still looks about the same yet. I think the signal could use improvement.

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14 Aug 2023 01:01 #277897 by PCW
Replied by PCW on topic Spindle and encoder
Can you post a current haslcope screenshot of the quadrature signals?

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14 Aug 2023 01:27 #277898 by smplc
Replied by smplc on topic Spindle and encoder
Yes.  The MDI g97 s1000 m3 entered but the portable tachometer read 645 RPM.  The Hal Meter pin hm2_7i96s.0.encoder.00.velocity-rpm and GUI RPM still shuffle.
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14 Aug 2023 02:39 #277904 by PCW
Replied by PCW on topic Spindle and encoder
Unfortunately, those signals are nowhere near actual quadrature.
Maybe a disk issue, don't know. Nothing that can be fixed in software
or settings.

Can you:
1. run the spindle at ~200 RPM
2. try adjusting the encoder while watching for
50 % duty cycle and 90 degree shift between A and B
(90 degree shift means A,B Signals change in the middle of the
B,A high or low period)

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14 Aug 2023 04:00 - 14 Aug 2023 04:30 #277909 by smplc
Replied by smplc on topic Spindle and encoder
I tried to adjust the distance of the encoder LED's from the face of the code wheel variably during 257 RPM but the Hal Scope did not show channels A and B 90-degree shift. I wonder if a reflective code wheel would have any improvement which might be worth a try. Any idea why the RPM is still shuffling?

Alternatively, I could obtain transmissive encoders which could mount on a customized bracket that mounts on the existing bracket. Another code wheel with perforations or slits might need to be manufactured. The Sherline Chucker Lathe spindle bore protrudes outside the headstock containing the pulley and a fastened retaining (face) ring which reinforces the 3C collet draw tube. A spacer and the other code wheel could go between the pulley and retainer.

Another option. Sherline did use a rotary encoder that was mounted on their early Chucker Lathes headstock. The Chucker Lathe pulley has two sheaves. The other sheave could be used to drive the rotary encoder.

Is 7i96s firmware known to have good quadrature, A and B channels about a 90-degree shift? Did the RPM GUI look stable?
Last edit: 14 Aug 2023 04:30 by smplc. Reason: Spelling.

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14 Aug 2023 06:32 #277916 by rodw
Replied by rodw on topic Spindle and encoder
Can you show a photo of your encoder setup?
Here is mine:
 

I am wondering if the scale on your printed disk is wrong or the LEDs are not properly aligned
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