Re: E-Stop Revisited

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Peter Cruickshank
<crankshaft_sg@y...>" <crankshaft_sg@y...> wrote:

> Hi;
>
> Ok, what's the conclusion on the E-Stop issue, should the big red
> button cut power to everything, or is s soft-stop good enough !
>
> I know that there are different opinons on this, but for the

general

> hme hobyist CNCer with a Sherline 5410, What's the recommendation ?
>
> Cheers
>
> PeterC

Absolute e-stop is pretty easy to accomplish. My e-stop button on my
controller and on the machine breaks a circuit that holds in the
contactor between the DC supply(s) and the motors. The contactor is
wired in a latching configuration so that voltage is required to keep
it "pulled in" and activated. I have two sets of limit switches. One
set is wired to perform Home functions. The others are wired in
series (Normally closed) and control a relay that will cause the
contactor to open if ANY of the switches are tripped, a wire comes
loose or there is a component failure in the circuit.

The need for e-stop with a small tabletop unit and small steppers is
reduced. It's not like the machine can cause you serious harm if it
goes uncontrolled. I am running a small engraving table that does
not have e-stop or limit switches. The only thing I miss is the
ability to do a return to home and zero the controller function.
MACH1 allows you to do that. My big table is a different story. It
has enough speed and power to cause real damage and I have limit
switches all over it!