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Author Topic: Interference with axis motors  (Read 8470 times)

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Re: Interference with axis motors
« Reply #10 on: September 19, 2017, 11:58:12 AM »
Hi,
well that certainly is a parallel port board pictured, and this is the board your using? It is a different setup than that pictured that comes as
standard with the mill.

Double check the OS of the PC.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
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« Reply #11 on: September 19, 2017, 01:58:14 PM »
Craig its definately win 10 pro 64bit ill check if i can post a picture for you power is just off at the moment as soon as its back up ill start everything and take photos for you and post it

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Re: Interference with axis motors
« Reply #12 on: September 19, 2017, 02:06:04 PM »
Hi,
a 64 bit OS cannot support a parallel port. The PCI card must therefore be a motion controller...do you know what it is?

Craig.
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'
Re: Interference with axis motors
« Reply #13 on: September 19, 2017, 04:41:43 PM »
I'd like to see pictures of the control box internals and the outside wiring. Interference comes up all the time on this forum as well as the 3D printing forums and when you see pictures it is an OMG! moment where you say "you actually thought that would work?".
I layout electrical panels and do panel wiring and I virtually never see interference problems because I am very careful about layout, wire routing, and shielding
Re: Interference with axis motors
« Reply #14 on: September 20, 2017, 03:54:43 AM »
Hi,
garylucas is right, can we see inside the controller.

The layout of the wiring is important. If you have separated the 230V inlet supplies you have gone a ways to prevent conducted interference.
If you have a cable carrying significant current like a spindle motor lying next to a signal cable carrying a few mA or less then the more powerful
cable will induce noise into its neighbour. Ideally you would separate the VFD/spindle and stepper wires from the signal wires. The stepper motor
currents don't seem to be giving you any grief so don't sweat them too much but you will need to separate both the 230V input cable to the VFD and
the cable to the spindle from the VFD from all the little signal wires and by several inches if you can.

The signal wires include the multicore parallel cable from the PC to the BoB, the Step and Dir plus Enables to the stepper drives and all the home
and limit switch wires. If you choose to use shielded cables earth only one end of the shield to one common earth usually at the BoB end.

For electrical safety you should earth the spindle motor back to the same common earth point along with the power earth. It is very important to
NOT accidentally earth the frame or other components of the machine with either shields or ground referenced signal wires, you will create a
ground loop which will induce noise into all the signals and drive you absolutely stark raving mad....I know...that's how I got to be like I am!

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'

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Re: Interference with axis motors
« Reply #15 on: September 20, 2017, 05:38:22 AM »
Some suggested  reading can be found in  Member's Doc's posted by Chaoticone.

External E stop requested, Limit switch triggered and/or other nuisances, EMI
http://www.machsupport.com/forum/index.php/topic,25616.msg180583.html#msg180583

RICH

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Re: Interference with axis motors
« Reply #16 on: September 20, 2017, 06:03:22 AM »
The problem of EMI can be complex and requires  understanding, definition, and experience.
A lot of folks don't understand elementary electronics let alone able to relate  to something they cannot feel or see. EMI / Noise / RF interference can be a real PITA. Knowing the source and possibly eliminating the culprit is the first or preferred step if possible. We often hear simple solutions and they get echoed over and over again. As Graig and Joe point out, good wiring practice can reduce the possibility of creating a problem. I won't ramble on as the subject is covered by many books BUT will say that sometimes it's just pure  black magic and has no explanation !

BTW, Ever read that FCC lable for something that states the device must accept un-wanted signals?  ::)

Back to the side lines, ;)
RICH
« Last Edit: September 20, 2017, 06:05:28 AM by RICH »
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« Reply #17 on: September 20, 2017, 02:29:52 PM »
Hi Rich

Thanx for the info im sure ill find the problem

Craig i havnt forgotten to take the photos they are replacing the powe cables to my workshop at the moment so there is no power. According to the contractors they should be done bu lunchtime tomorrow then hopefully i can get everything on again to take the phots for you.

Ill update you if i get the problem fixed

Thanx for all the help sofar

Mav

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« Reply #18 on: September 20, 2017, 02:33:05 PM »
Can someone please explain debounce in Mach3 what exactly does it do

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Re: Interference with axis motors
« Reply #19 on: September 20, 2017, 02:51:38 PM »
Hi,
debounce is a bit like a filter. If you set it Mach will wait until the signal has been constant for a period of time before it will act on it.

Imagine a big noise spike gets induced into one of your limit switches. If Mach responded instantly the machine would stop immediately thinking
that its preventing a crash. The big noise spike however will be over in nano seconds, if Mach waits for several micro seconds before responding
it would realise that the limit signal was false.

It is called debounce because it was originally for a switch. Often as a switch as it either makes or breaks its connection it will jitter and make-break several
times before it settles into its new state. A reasonable debounce setting in Mach prevented a 'bouncing' contact to cause multiple events.

It can be useful for suppressing noise but if the source of noise is quasi-continuous it won't work. As has already been posted its better to prevent the noise
from being 1) generated and 2) transmitted.

Craig
'I enjoy sex at 73.....I live at 71 so its not too far to walk.'