Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: biggermens on July 09, 2018, 07:58:54 PM

Title: Help needed, limit swtch trip when turn on spindel
Post by: biggermens on July 09, 2018, 07:58:54 PM

Hello every one, I am stuck here

I got my machine all wired up, all with shielded wire
Machine seams to work fine until you turn on spindle and it trips a limit stop ( what ones? i don't know )
I took the power wire for the spindle out, to get it away from the rest and it did not really help much,
when you run the spindle at 1/2 rpm the machine runs but runs like carp very slow to respond at the keyboard strokes

Using 2 parallel port cards one on board that drive the steppers and the other for everything else

I am really stuck been on this for days
Thanks in advance 
 

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: joeaverage on July 09, 2018, 08:04:10 PM

Hi,
electrical noise on the limit switch line. RC low pass filters.

Craig

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: biggermens on July 09, 2018, 08:49:40 PM

All the wire on the limit switches are shielded
and the limit switches are just micro switches

I am looking up the RC low pass filters right now


 

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: joeaverage on July 09, 2018, 08:58:33 PM

Hi,
you should first try to eliminate the electrical noise emanating from your spindle.

Shielded wiring and low pass filters are all well and good, but the noise is still
there, eliminating the noise should be your primary goal. Shielding and filtering
reduce the suseptability of the wiring to noise only.

What kind of spindle do you have and how is it controlled?

Craig

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: biggermens on July 09, 2018, 09:07:42 PM

Every wire on that machine is shielded, i made sure everything is bonded
even the power going to the spindle is shielded 

My Spindle is pretty much this pile of junk hehe

https://www.banggood.com/500W-Spindle-Motor-with-Speed-Governor-and-52mm-Clamp-for-CNC-Machine-p-1202031.html?rmmds=search&cur_warehouse=CN

its 220v ac and out 100V DC i use the pot to control the speed and use a solid state relay to turn it on and off but disconnected the relay to try to eliminate possible problems 

Thanks

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: joeaverage on July 09, 2018, 09:42:55 PM

Hi,
thats a DC motor and the ouput of the controller is PWM, rich in high frequency harmonics
just the thing for screwing up sensitive signal lines!

I would recommend a decent line filter on both input and output.

Something like this:

http://nz.element14.com/schaffner/fn2020-16-06/filter-16a-chassis/dp/1191368# (http://nz.element14.com/schaffner/fn2020-16-06/filter-16a-chassis/dp/1191368#)

Note the filter on the output side of the controller could come under serious stress due to
the high frequency PWM, but still worth a go to tame the noise.

Craig

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: biggermens on July 09, 2018, 09:54:07 PM

Right on, i use the same unit on the output side ??

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: joeaverage on July 09, 2018, 10:03:23 PM

Hi,
yes, its possible the high frequency current may damage the line filter so don't go
spending up bigtime. Even a modest line filter with a comensurately small capacitors
will help the noise situation, hopefully without the noise current wrecking them.

Craig

Title: Re: Help needed, limit swtch trip when turn on spindel
Post by: biggermens on July 09, 2018, 10:05:59 PM

Awesome Craig Thank you very much, I will try to get a couple in the morning
You da best ;)