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Author Topic: grounding issue? spindle help....  (Read 2964 times)

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Offline BarryB

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grounding issue? spindle help....
« on: January 07, 2010, 01:30:47 AM »
Hello, I've got my machine all hooked up, 5 axis, with limit and homing switches, unit accurate.  It's all working except for the spindle control.  I'm using a CNC4PC C23 rev 3 board, smooth stepper, Hitachi x200 vfd, and a spindle from HSD.  If I set up Mach to work to trigger the relays 1, or 16 to turn on the spindle, it crashes mach3 immediately.  At first I thought it was my settings in mach that was the issue.  Then I unhooked the spindle from the C23 board completely.  I can then trigger the relays on Mach3, and it thinks it's turning on a spindle.  You can hear it trigger and then turn off when you, disable the relay, no crash.  Now, here's the weird part.  The spindle itself is not connected to the C23 board, but if I have Mach 3 running, and I turn on the spindle by touching the two wires together that would have been connected to the relay, this crashes Mach3.  Note, they aren't connected to the C23 board, nor did I tell Mach3 to trigger the relay.  This is me touching the wires together by hand, away from the board.

Any idea what could cause this?  I'm currently connecting these to be internally powered/sourced from the VFD.  So it's got a 24v signal.  I haven't tried sinking the source.  I have tried connecting all my grounds together (5v, 65v, and the ground from the DC terminals on the VFD), so ideally nothing would be floating relative to something else, this didn't do anything.

I'm at a loss.  Any guidance would be really appreciated.

Offline Hood

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Re: grounding issue? spindle help....
« Reply #1 on: January 07, 2010, 02:52:00 AM »
You could try increasing the filtering in the SS plugin but maybe a real line filter will be needed as VFDs can be noisy, think Jeff Birt sells some.
Hood

Offline Fastest1

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Re: grounding issue? spindle help....
« Reply #2 on: January 07, 2010, 09:05:17 AM »
Now, here's the weird part.  The spindle itself is not connected to the C23 board, but if I have Mach 3 running, and I turn on the spindle by touching the two wires together that would have been connected to the relay, this crashes Mach3.
Where is the spindles ground connected to? the chassis of the controller, machine and or computer? Can you isolate or remove the spindle ground temporarily and test it ungrounded? I have/had these issues with every change or addition of hardware it has caused much late night reading. Guidance might not be the right term for my wisdom. Your problem does sound similar to issues I have had.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)

Offline Jeff_Birt

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Re: grounding issue? spindle help....
« Reply #3 on: January 07, 2010, 10:01:50 AM »
You have a noise issue. Spindle motors (well any motors really) generate a LOT of electrical noise when starting. Very often this will cause other nearby electronics to have problems. A VFD can compound problems as they are very often good noise production units as well. You need a line filter and/or line reactor depending on what type/size of VFD you have.

If you have a smaller 110V single phase VFD driving a 1 HP or smaller motor you can probably get by with a unit like this: http://soigeneris.com/cncparts2.aspx. If you have a larger drive/motor or a three phase input drive you'll need to look at your drives documentation  to see what they recommend. Most drive manufacturers will have reactors/filters available for their drives. A line filter like the one linked to above should be placed as close to the drive as possible. Depending on the size of the drive, type of power input etc, you may need a filter/reactor between the drive and motor as well. Take a look at your drives documentation to be sure.

The line filters I sell (above link) work very well but you just have to make sure that it will fit your situation. Feel free to send me a PM or email if you have any questions.

Happy machining , Jeff Birt