Silly me ...
this mail was supposed to go to the mailing list but my email program
keeps replying to the original sender and not to the "Reply-To" ...
I just noted that just now reading Ray's response to me.
Ah well, this explains why I did not see my mails return to myself via
the list.
Below the mail intended to go to the list.
I'm still designing so any information is welcome. I'll see if I can
post some schematics with the ideas also.
Rob
Quoting Ray Henry <[EMAIL PROTECTED]>:
> My reaction here is for the newbee wiring enthusiast because I'm pretty
> certain that you guys already know that silicon mediated estop is only
> permitted under some very strictly controlled situations.
Yes, that's exactly what I have against using the E-stop in EMC as
'real' E-stop. But it's good it is there for those newbees that are
keen to get there machine running before completing it.
But as always: one should never operate a machie (even for testing)
before limit and E-stop switches are installed.
> To qualify we pretty much
> need a normally closed loop of mechanical switches that pulls a relay
> rated to break the current supplied to moving parts.
What I came up with: a normal closed E-stop (the switch is now mounted
on my machine) connected to relays. Both the motor controllers and the
milling spindle are powered by the relays such that on an E-stop all
power is removed from spindle and motors. The stepper motors are
connected to ball-screw axis and removing power from the motors
removes the force on the axes (and thus on spindle and workpiece or
anything in between moving parts).
A second relay is connected to the E-stop in of EMC so that it knows
there is a panic.
Furthermore, the relays also serve as machine switch: normal Red/Green
buttons and a key-switch. So after hitting the Emergency button I
first need to reset it and then push the Green ON button to resume
operation.
Somehow I need multiple relays to be able to power-off everything
(including PC and other equipment connected) using the red OFF button.
My milling spindle (2 kW 18000 rpm max.) is controlled by a Toshiba
VF-S11 3-phase inverter that has an over-torque output signal (on a NC
relay output).
I was thinking to use that as an extra input for the E-stop so it will
also stop if something weird happens. In the VF-S11 I can set the
power level at which it has to trip, 2 kW is a lot of power ...
Rob
P.s: I had no time to add photos to my webpage yet
must make shiny objects first ...
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