On Thursday, September 15, 2011 05:50:08 AM Ben Jackson did opine:
> I have pin 1 of my parallel port connected to a relay that isn't driving
> anything yet. When I start EMC2 I hear it click on/off. If I control
> it explicitly with M64/65 (or other logic) it works fine, but even if I
> do "setp parport.0.pin-01-out 0" it clicks at startup. I'm sure that's
> the pin because if I "setp ... 1" it only clicks once and stays on.
>
My stepperconfig generated .hal says parport.0.pin-1 is estop_out. I
believe this is the commonly used pin for that.
> This might be happening with other outputs as well -- I always noticed a
> stepper clonk at startup which might be the drivers enabling briefly.
More than likely, that is the drivers powering up the motors, and not
having a history of where in the microstep 'cycle' the motors may have been
when powered down or emc stopped, they instead go to a fixed, full step std
home position, which could be a movement of nearly a degree in a 200 step
motor. Some driver docs will note that, but until emc keeps a modulo
number of chosen microsteps from this imaginary position, in signed
notation so it could issue those steps and put the motor back in that exact
position, there will remain this teeny position error over a shutdown and
restart cycle.
I personally have not had it wreck a partially carved part with my toy
mills 20tpi screws, this motion is well under a thousandth and disappears
into the backlash comp noise. For those with faster ball screws, I suppose
it could be a problem.
Cheers, gene
--
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soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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