Chinese HF Spindle and EStops problems.

[wjfiles]

My Home built has HobbyCNC Pro board and 3 Steppers. I use Mach3. I recently installed a chinese spindle and VFD. Now I get random Estops and cannot complete a project unless I disable the limit switches in Mach3.
I have used expensive shielded cable between the spindle & VFD, grounded both ends as recommended. I have uesd a good quality shielded cable for the limit switches grounded only at the controller board end.
My limit switches are ElCheapo from Jaycar, these have been fine until the spindle update. Obviously some Hf interference somewhere.
Any Ideas or suggestions how I can eliminate this from happening.
Maybe some additional electronics ???
Any help will be much appreciated
WJF

[Al_The_Man]

Do you have a central ground point?
Your PC M.B. is usually grounded through a chassis screw, Try taking a ground from either the port common to ground or the PC power supply common direct to the central ground point where the VFD grounds should also terminate.
Make sure the service ground, VFD ground and Motor frame ground conductor is also connected to the star ground point.
Al.

[wjfiles]

Thanks for the quick response Al, I will try this tomorrow.I still feel uneasy as some of the jobs I want to do will take 3 to 5 hours and I would like to eliminate the possibility of false triggers if there is a way to do it. That way I can do other jobs ( within ear shot) without having to sit at the router.
WJF

[jeffrey001]

Some peoples with regular problem with limit switch often use higher voltage running through their cables, like 24 volts and pass that signal through a relay which are hook up to a 5 volts supply.

That way, the cables are less prone to pick up noise from high voltage parallel running cable.

Just my idea, Jeff

[bharbour]

You might try putting a 0.1uF disc capacitor across the EStop switch inputs. That will go a long way to filtering out noise picked up by the EStop wiring. As Al's grounding suggestions indicate, the EStop wiring is not the only way into the sytem for noise.

Another fix that I have seen mentioned, but not used is extending the debounce timeout on Mach for the EStop to a much larger number than the default value.

Good Luck,
BobH

[machineoverman]

Chinese Spindle - problems

that's the problem!

when will we learn tsk..

[Zig]

yeah ..probably Chinese made motherboard too..

[wjfiles]

I have tried most of the suggestions but no avail. I have also move the VFD further away from the machine and computer without any effect.
The home switches are not affected . Only the limit switches
I also noticed that with all components switched on but the router not doing anything Mach keeps triggering a reset.
One question, I have seen posts that say you should not ground the shield at both ends.The spindle "manual" says to ground both ends of the cable from VFD to Spindle. Why the difference ??
At the moment I have, the computer chassis, power supply and controller board, Vfd and spindle all grounded to the common AC input.
Stepper wires from Hobby CNCPRO are not shielded.
Maybe I should bury the VFD in a hole in the back yard.

[Zig]

EMI ( electromagnetic interference)can be radiated or conducted.
It is probably originating within some area of high frequency high current switching circuitry.
There are filtered power distribution boards to be had. Also there are filtered GPO to be had. See if you can locate a powerboard which has a mains EMI filter and alternatively connect only your inverter to it or only the powersupply which drives your machine electronics ( break out board .. stepper powersupplies PC )

This will provide a bit of isolation between the suspect spindle inverter and innocent everything else. ( You have not told us how for example the emergency stop circuitry is supplied with power only that it worked ok [rior to addition of spindle electronics . It is possible things worked .. but just andthe additional noise is now tripping things out )

So try the above.. divide and conquer.

[Al_The_Man]

Originally Posted by wjfiles One question, I have seen posts that say you should not ground the shield at both ends.The spindle "manual" says to ground both ends of the cable from VFD to Spindle. Why the difference ?? .

All conductor shields should be connected at one end only, I use the Earth star point end, however there should also be a ground bonding conductor to go to all metalic parts of the machine, i.e. motor frame, VFD ground, Moving Gantry, Enclosure Cabinet frame, service ground etc. back to the star point.
The three conductors from VFD to Motor should be tightly twisted together, any ground conductor should not be twisted with these three if avoidable.
Al.

[flashgordon]

I agree, grounding should probably be at one end only. Both ends might generate a loop which in turn will generate a current in your ground. So no longer 0V.

My 2 cents
Gordon

[Zig]

WJ..
we met at the recently held brisbane group meeting.

If you still have problems , may be I can have a look at your instalation.

I am about ten kilometres( as the crow flies) north of b?ridge