Feature request, but must be universallly accepted by ALL blanker authors

Adam Nielsen a.nielsen at shikadi.net
Sun Oct 4 11:26:50 UTC 2020

> > This is quite true, and if it can't be fixed, I will be forced to
> > install a smash it switch that interrupts machine power.  But I've
> > some pretty high cap supplies that can keep it moving for several
> > seconds after the switch has been fisted.  A software e-stop OTOH can
> > stop it dead in the water in a very few milliseconds.  
> That sounds trivial to fix. Have the red stop button operate relays
> that interrupt the circuits exactly where the software would.

Often with high power motors like this, interrupting the power causes
them to gradually spin down to a stop thanks to inertia, but what the
software does is provide electronic braking by changing the motor
control pulses so that the motor is actively slowed down to a stop
very, very quickly - which of course requires the power to be on to do
that.  This can stop the spindle in a fraction of the time compared to
what you'd get by cutting the power.

What you really need is an e-stop switch where the software is
signalled immediately, but the relays or whatever is controlling the
power supply are switched off only after a short delay of a few
tens of milliseconds.  This would give the software time to
electrically brake the spindle and only if that fails does the power
get cut and the spindle free-spin to a gradual stop as a last resort.


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