The following statement sounds like the prelude to many more posts regarding
problems (real or imagined) that might've been eliminated by following some
knowledgeable advice of adding a capacitor to the signal lines to see if a
problem might be noise-related.

*** "I am not an electrical engineer, unfortunately, but I wonder if a
capacitor and a small resistor could help with noise suppression." ***

IIRC, the advice was to use a small-value capacitor.. with the resistor
being interjected by the OP.

--
WB
..........


"Ignoramus29468" wrote in message
...
On 2010-08-27, Larry Jaques wrote:
On Thu, 26 Aug 2010 18:51:13 -0500, Ignoramus29468
wrote:

On 2010-08-26, Jon Elson wrote:
Ignoramus29468 wrote:


With that fixed, the mill is no longer chattering.

No need to be embarrassed, it happens.
I have one more weirdness: under heavier cuts, the mill triggers a
limit switch error for a reason that I cannot understand. But if I do
not push it quite as hard, it does not do so. I tend to think that it
is something related to the hardware of limit switches and maybe some
vibrations.
I'd be more likely to believe electrical noise, from either the spindle
VFD or the servo drive. Both use PWM, and produce high-voltage pulses
with sharp rise and fall times. These pulses may get stronger under
greater mechanical load.

Are you sure it is a limit switch error and not a following error?

I am positive that it is a limit switch error.

So have you individualized them yet, Ig? If not, do so and try the
same cut. Let us know if it still errors out.

Not yet, no. I was making some chips today (a lot of)


I sort of agree with your explanation about electrical noise.

I tend to blame the wires from servo amps. I do use twisted pairs, but
maybe I did a bad job somewhere.

Twisted pairs will certainly limit noise transmittal.

I am not an electrical engineer, unfortunately, but I wonder if a
capacitor and a small resistor could help with noise suppression.