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Author Topic: Help with Spindle Index please  (Read 6842 times)

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Help with Spindle Index please
« on: December 15, 2009, 05:41:23 PM »
Hi all, well I'm slowly getting the rest of my lathe functions up.  I've added a slotted sensor with opto-interruptor (salvaged from an old printer) to the spindle, and this seems to operate in that the LED on the diags screen goes off or comes on (depending on active low setting) as the slot passes the beam.  However when the spindle runs the S_true DRO doesn't show the speed, only a steady zero!  When running the LED blinks occasionally which doesn't surprise me as presumably the PC is sampling it and won't see all the pulses.

I haven't checked the pulse width as delivered to the breakout board but the slot width was calculated to comfortably exceed the Mach3 minimum requirement - would need to break out my old 'scope which hasn't been switched on in 10 years for this! (what an excuse...) - before I do this has anyone met this problem before and could suggest a solution please?

Thanks,

John.

Offline Hood

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Re: Help with Spindle Index please
« Reply #1 on: December 15, 2009, 05:51:56 PM »
Make sure you dont have much if anything for the Index Debounce on General Config page. Other than that I think you are going to have to blow the dust off the scope.
Hood

Offline RICH

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Re: Help with Spindle Index please
« Reply #2 on: December 15, 2009, 08:06:22 PM »
Make sure that you have Disable Spindle Relays (unchecked) and Use Spindle Feedback in Syn Modes (checked )
in prots & pins > spindle setup. You may want try lowering the Index Debounce and interval.
I will assume your using version 3.042.032 , you need to do a M3 to turn on the spindle for rpm to display.
If not any of those then you need to look at the opto output signal, trace the path from  the opto to and from the BOB and to the pc.
RICH
 

Offline Fastest1

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Re: Help with Spindle Index please
« Reply #3 on: December 15, 2009, 09:53:03 PM »
Having just been there this week, if you have not set one of these up before be ready for a challenge. Once up and running it is incredible but before that I wanted to kill everything. As mentioned above the low index debounce setting is important (0-1) if you can get away with it. The index led on the diagnostics doesnt really keep up (it bothered me too) if the motor is on but if you manually turn the spindle the opto sensor "sees" the leading edge very accurately and does it at speed too. I also get a random rpm displayed very quickly with erratic changes especially at low rpm the motor speed doesnt actually change just the display. It doesnt seem to effect anything and the numbers it displays are huge like 48924 rpm but synchronization is spot on.
« Last Edit: December 15, 2009, 09:55:51 PM by Fastest1 »
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: Help with Spindle Index please
« Reply #4 on: December 16, 2009, 04:11:10 AM »
Thanks for all the replies, lots of things to try!  I'll post again when I've had a go.

John.
Re: Help with Spindle Index please
« Reply #5 on: December 16, 2009, 04:28:09 PM »
Well, I can report some progress.  I unchecked the disable spindle relays box, which seemed to be the key so that I could "switch on" the spindle; also reduced the debounce number from 200 to 50.  Now displays something which is related to spindle speed but approx half what it should be, and negative!

What is the significance of the "debounce interval" parameter please?  I have this set to zero at the moment.

I will continue to play!

John.
Re: Help with Spindle Index please
« Reply #6 on: December 16, 2009, 04:30:40 PM »
By the way Rich, is "doing an M3" what clicking the spindle button does?

Offline Hood

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Re: Help with Spindle Index please
« Reply #7 on: December 16, 2009, 04:39:01 PM »
Debounce interval is for general inputs, Index Debouce is specifically for the Index pulse.
 Have you tried less than 50 in the Index Debounce as usually any more than 1 or 2 can cause problems.
Hood

Offline RICH

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Re: Help with Spindle Index please
« Reply #8 on: December 16, 2009, 05:15:06 PM »
YES, just click the spindle button ....even if you are turning the motor on manualy or you will not get an  rpm readng. I actualy have M3 as part of my Iniatlization String in config...... NOTE THAT I AM "MANUALY" TURNING MY MOTOR ON. You may want to provide an iniatialization via a macro like it shows in the write-up in Appendix "C". This way you can always just type M1111 in the MDI and it will reset your lathe back to YOUR prefered state.
You may forget for instance, after threading. to provide a G94.

Index Debounce here is 10 and works, like Hood said, play with number some by lowering it.

RICH
Re: Help with Spindle Index please
« Reply #9 on: December 16, 2009, 06:09:23 PM »
OK, thanks for suggestions, I have tried very low numbers including zero.  The indicated speed is about half what I expect (but only going by the plate on the lathe, but I assume that Myford are right); it has a "-" sign in front of it; and shows a finite speed even if the lathe is stopped - I think I have some interference!  Time to dust off that 'scope I think!

John