Retrofitting a 1986 Maho MH400E

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01 Aug 2018 06:36 - 01 Aug 2018 17:10 #115284 by RotarySMP
I had another look at the MuellerNick video, and see what you mean. Did you notoice that Nick posted a video last week? He has been absent from the internet for a few years, but the video is a teaser of what looks like a new workshop.

I think Andy's solution with the harmonic drive has got to be the better approach. However, as tempting as it would be to get started on a fourth axis, I am going to be strong and continue to work on my two axis MAHO, hopefully on day fixing the vertical encoder to make it a three axis machine.

Although I was counting on Bob for quality assurance, it turns out he was napping on the job, day dreaming about rotary axis, and failed to notice that I only wired one side of a switch...

So I had to fix that.

Then started mounting the two PEC-16 rotary encoders.




These ones have the push button function which will be set up to reset the feed and jog overrides back to 100% and a set standard respectively. Luckily there were two spare nodes on the 5X5 matrix_keyboard, so I can wire those buttons in there.
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I'll wire the encoder signals to the 7i77 with a separate CAT5 cable.

Need to go to Conrad and get some connectors, and knobs.
Mark
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Last edit: 01 Aug 2018 17:10 by RotarySMP.
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01 Aug 2018 14:19 #115311 by andypugh

J Green wrote: Can a resolver do .001Deg resolution ?


Not directly.
www.tamagawa-seiki.com/products/resolver...olver-fa-solver.html
Shows an error of between 7 and 15 minutes of arc, that is 0.25 degrees.
But if mounted to a 100:1 harmonic drive that is 0.0025 degrees.

It is much easier to make an incremental encoder accurate and linear, and quite hard to make a resolver linear. (which is why they are expensive). Typically a resolver (being analogue) will have worse linearity/accuracy but better resolution than an encoder.

My Harmonic drive 4th axis actually has an encoder.
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05 Aug 2018 11:03 #115633 by RotarySMP
Yesterday I wired up the Encoders. I'll recycle the exisiting 21x 0.14mm² cable which connected the Phillips keyboard, and put two connectors on this end. Bad planning on my mark, as I could have done it with a single dSub 25.



Mark
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