Re: Control Pendant/Panel layout for your comments

I'm with you. Currently my E-Stop button is a NC in series with the
latching contact on my enable relay. When pressed, the relay drops
out and cuts the power to the stepper drives, the mill's spindle
motor and invokes the spindle clamp and brake. In order to re-
start, the "Start" button must be pressed. Using the "Start" button
to kick in the enable relay means that transients and other stuff
will not affect anything when the PC starts up. It works as well as
other schemes (like the charge pump circuit), but only requires a
switch latched relay contact.

Regards,
Jeff

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "caudlet" <info@t...> wrote:
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, wanliker@a... wrote:
> > In a message dated 10/17/2003 12:42:48 AM Mountain Daylight
Time,
> > jeff@w... writes:
> > It works as well as
> > other schemes (like the charge pump circuit), but only requires
a
> > switch latched relay contact.
> > In my thoughts it works much better as no power, no movement.
And
> no auto
> > start after any power outage either. Too much solid state stuff
> fails in a
> > shorted mode and in some cases can power things up. That can be
> very dangerous.
> > And in my mind there has to be one E Stop that isolates
> power,,,,,,,,period.
> > bill
>
>
> Bill is right. E-stop should NOT be initiated by the control
> software. E-stop should manually kill power to the motors and
inform
> the software through feedback it has done so. By using a latching
> relay as the DC power control any condition that even momentarily
> interrupts the power to the relay shuts things down. By wiring
the
> limit swiches in series Normally Closed and making it part of e-
stop
> protects the machine from running or starting if a fault condition
> exists.