Starting from scratch (again) - Spindle encoder Question

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03 Jan 2020 08:08 #153870 by Clive S

I see the index slot but just noticed the 3rd sensor,
Please elaborate, is it quad or directional?
Thanks
M

For threading you just need Z +A but for ridged tapping you need quad. for direction so Z + A + B

The sensors are adjustable to get the quad correct.

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03 Jan 2020 14:24 #153892 by Todd Zuercher
If you have an existing index sensor, just use it. Then it would not matter if the encoder is connected 1:1 (You'll just need to figure out how many pulses/rev your ratio gives you.)

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03 Jan 2020 16:30 #153902 by mooser

I see the index slot but just noticed the 3rd sensor,
Please elaborate, is it quad or directional?
Thanks
M

For threading you just need Z +A but for ridged tapping you need quad. for direction so Z + A + B

The sensors are adjustable to get the quad correct.


Thanks

I've never tried the rigid tapping on the lathe, normally just slowed the spindle way down and used the tailstock / drill chuck and reversed the spindle (m code) when the tap was near it's end :)
If I get the encoder working I might have to experiment with rigid taping
M

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03 Jan 2020 16:32 #153903 by mooser

If you have an existing index sensor, just use it. Then it would not matter if the encoder is connected 1:1 (You'll just need to figure out how many pulses/rev your ratio gives you.)


I'm hoping not to have to buy a different encoder and the two I have are both non-indexed so my plan is to use the existing sensor for index. Without worry on the index I should be able to deal with a spindle / encoder ratio even if it's just lying about the number of counts (or at least I think so)
M

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08 Jan 2020 17:11 #154322 by andypugh
You can use a single pulse.
Connect that pulse to A and Z of the counter and set the counter to "counter mode" so that it does not need a B phase.
Make sure you use the "position-interpolated" output of the encoder counter module.

Adding more slots for A will make things better. And a full quadrature counter would allow for rigid tapping (as mentioned). You can't rigid tap without all three phases working as the system can't detect spindle direction changes.

You could keep an eye out on eBay for "elevator encoder" as some of those seem to feature a very large through-hole and might direct-fit to the spindle.

Are there any gears in the head? You could potentially derive A and B using hear tooth sensors on the bull gear, if the lathe has one.

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26 Jan 2020 00:07 - 26 Jan 2020 00:09 #155767 by mooser
Another small step forward
Timing gears showed up yesterday and I've got the one bored out (lathe works but pretty awkward without a pendant or any form of MPG:) and fit to the spindle tube. Hod ot machine off the existing hub completely but it's the smallest one I could find that still had enough meat left once opened up



Now to make some form of bracket to hold the encoder down below there and run some wires.
Once the encoder is working I thing can move on and tackle the gears
M
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Last edit: 26 Jan 2020 00:09 by mooser.

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05 Feb 2020 01:38 #156553 by mooser
2048 line US Digital Encoder with index installed and working correctly, onward to the gears

M
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