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.

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.

i
Can i ask how its wired in EMC? The limits switches on my control use
24 volt DC and are wired NC to an opto isolator. This is a very noise
resistant design. I'm curious if you can do the same in EMC.

Karl