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VFD problem
« on: June 25, 2016, 09:34:43 PM »
Hi
I have been running the roadrunner gcode to get use to my machine coordinates, thought I would run with my spindle on also no tool. When I power up the spindle I get a limit switch tripped, when I reset I get a Emergency e stop requested, I can run the program with the VFD in power but if I start the spindle I get the emergency stop. I have the power cable to the spindle shielded and grounded at the VFD. I read recently that it should be grounded both sides is this my problem or could it be something else
Thanks Bill
Re: VFD problem
« Reply #1 on: June 25, 2016, 10:31:37 PM »
Hi
I wanted to add to what I wrote might give some clues. was reading on the web that the VFD should be on its own circuit, switched that and spindle can run now a few seconds before tripping the limit, also set the debounce to 5 that makes it last a few seconds longer. but still is tripping

Offline Tweakie.CNC

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Re: VFD problem
« Reply #2 on: June 26, 2016, 03:07:35 AM »
VFD’s emit copious amounts of electrical noise in the RF spectrum and this can easily be picked up by any un-shielded wiring and subsequently interpreted by Mach3 as a signal (EStop, Limit, etc.).

Just a couple of suggestion…
Check that your EStop and limit switch wiring is made with good quality shielded cable with each shield connected (at one end only) to the ‘single point Earth’ at the controller end.
Your Spindle motor should be wired with shielded cable again with the shield connected, at one end only to the single point Earth.
Check your VFD manufacturers wiring instructions to make certain you have the Earth connected correctly.
Check that your single point Earth is indeed connected to EARTH.
Increase your debounce to 500.
Fit 0.1uF minature capacitors between each used input to your breakout board and the single point Earth.

I hope that one, or more of these suggestions may cure your problem.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: VFD problem
« Reply #3 on: June 26, 2016, 07:05:50 PM »
Hi Tweakie
Posted earlier but don't see it up, wanted to say thanks again the debounce worked at 500. I ran the roadrunner a few time with the spindle running with no issues.
This afternoon I put a pieces of Styrofoam on the table and ran the program with out it touching the foam went fine. Then I ran it with the end mill cutting in about a 1/4"deep, both times I ran it it tripped a limit about 3/4 thru the program looked about the same place, I reset both times and it finished with no problems. any idea whats going on.
Bill
I had said I posted earlier and it's not showing, what I had asked is should I play around with that 500 setting on the debounce setting perhaps to see what the lowest setting it could be

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Re: VFD problem
« Reply #4 on: June 27, 2016, 02:37:37 AM »
Hi Bill,

You should regard the debounce as a 'sticky plaster' rather than a cure. The fact that increasing it to 500 created improvement I think confirms that you have a problem with electrical noise which should now be tackled.

Ideally, you should be able to run your system with debounce set to zero but the 500 figure that I suggested generally protects against the odd EStop caused by mains borne spikes etc.

Check that your shielding and earthing are all good.

(It was intended as advice to beginners but this document may be helpful  http://openbuilds.com/threads/electronics-101.693/)

Tweakie.

Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: VFD problem
« Reply #5 on: June 27, 2016, 02:48:00 PM »
ThanksTweakie

That write up was good, will start working on this advise.
Bill
Re: VFD problem
« Reply #6 on: June 27, 2016, 08:07:50 PM »
Hi Tweakie
I was looking at the capacitors online. I don't know much about these, how would something like that be added on. is there a terminal bar for something like that
Bill

Offline Tweakie.CNC

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Re: VFD problem
« Reply #7 on: June 28, 2016, 02:02:49 AM »
There is no definitive way but generally one lead from the tiny capacitor is connected to the same point on the breakout board as an Input (EStop, limit etc.) and the other lead from the capacitor is extended and connected to the single point Earth. Obviously any exposed wiring is insulated. This is repeated for each used Input.

Sorry but I don’t have any suitable photo’s to illustrate the process.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: VFD problem
« Reply #8 on: June 28, 2016, 03:17:02 PM »
Hi
Just so I understand, The one lead from the capacitor will share the input place on the board with the input wire say for a limit switch. The other wire from the capacitor will go to were I have the shielding grounded. Is this correct, sorry I have no experience with this.
Thanks again for your interest.
Bill

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Re: VFD problem
« Reply #9 on: June 29, 2016, 01:58:28 AM »
Hi
Just so I understand, The one lead from the capacitor will share the input place on the board with the input wire say for a limit switch. The other wire from the capacitor will go to were I have the shielding grounded. Is this correct, sorry I have no experience with this.
Thanks again for your interest.
Bill

Hi Bill,

You are quite correct sir.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.