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spindle problem
« on: February 06, 2015, 11:57:59 AM »
Hi everyone got a problem someone might know what it is. Been running my Denford triac mill on Mach for some 3 years with a DELL OptiPlex 330 computer with no problems. Then last year got through 2 motherboards on my computer for no apparent reason. However I have noticed that when applying M5 spindle stop the spindle stops then starts creeping, not every time but most times. Just put another motherboard in and M5 stops the correct rev but the spindle continues to rotate at about 100 revs. I think I have a back feed form the BOB back into the computer. Also when I turn the Triac on the spindle revs start up without a command. Think I have a voltage feed back problem.
Any suggestions

BOB and spindle plug in card from cnc4you and the spindle drive is a 1988 LYNX 180v drive

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Re: spindle problem
« Reply #1 on: February 07, 2015, 03:38:35 AM »
Is your breakout board isolated?
Hood
Re: spindle problem
« Reply #2 on: February 07, 2015, 03:50:31 AM »
Hi Hood, I think so but will check later today, when you say isolated do you mean not in contact with any metal parts connected to the mill or earthed? Sorry mate not very clear on electrical terms. I have noticed the 0v and 10v control wires are close to a doughnut transformer and was wondering if this was the problem as when I turn on the machine the spindle has a surge up to 1000 revs for a split second. The spindle then behaves itself for 10min then starts to slowly rotate at say 100 revs for the rest of the day.

Jim

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Re: spindle problem
« Reply #3 on: February 07, 2015, 04:05:51 AM »
I was meaning optically isolated from the parallel port. Some breakout boards have no isolation so if something goes wrong on the output side of the BOB it can be transferred right through to the parallel port. If it is isolated then the opto isolator would possibly blow but your PP would be protected.

Regarding the 0-10v wiring, ideally it should be shielded and the shield grounded at one end only and if it is close to the transformer then that could very likely be a source of noise.
Hood
Re: spindle problem
« Reply #4 on: February 07, 2015, 10:09:36 AM »
Do you have any spindle spin up/down delays set in the Ports & Pins/Spindle Setup screen?  Ive noticed that my spindle turns very slowly for a few seconds after turning it on & right back off due to a 5 second delay I setup in mine.  Just a thought.
Milton from Tennessee ya'll.
Re: spindle problem
« Reply #5 on: February 07, 2015, 10:32:04 AM »
Triac's require a minimum load (amps) to operate correctly, i.e. turn on and off. If there isn't enough loading the triac can still conduct voltage at a reduced level which could be the spindle creeping you are seeing. The "gate" part of the triac could be partially shorted to the output and causing voltage to feed back to the bob too. I would replace the triac with a relay and see if the problem clears up.
Re: spindle problem
« Reply #6 on: February 07, 2015, 10:39:11 AM »
Thanks for the thought geh7552, I have misled you Denford Triac is the machine not the electronic part. I only know this because when looking for parts for my machine I once typed in Triac in ebay and got loads of electronic components. Thank for the thought mate.
Does anyone know where to get a 25 pin to 25 pin optical isolator from, or is it a new optical BOB from diycnc. Jim

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Re: spindle problem
« Reply #7 on: February 07, 2015, 03:08:47 PM »
Think you would be a lot cheaper with a BOB than going for an opto connector.

First thing I would do is shielding and moving the cable to see if that helps.

Hood
Re: spindle problem
« Reply #8 on: February 11, 2015, 02:26:51 PM »
Hi Hood, re routed the control wires and shielded them as you suggested. Solved the problem but thinking I will move to smooth stepper control, which is best USB or Earthnet?
Jim

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Re: spindle problem
« Reply #9 on: February 12, 2015, 01:49:28 PM »
Ethernet is definitely the better of the two.
Hood