My take is E-stop is E-stop. It should remove high voltage to your
drives/spindles. In some setups it might be a fairly unpleasant button to
press, will your Z axis fall a little before the brake kicks in? Will your
VFD hate you for suddenly disconnecting it from the mains and preventing
it from doing whatever braking tricks it might normally do to slow down
your spindle? Will all your drives lose position counting? etc.
When the system is out of estop but not Machine Power, all drives should
have high voltage applied but their enable inputs should not be driven
high. The machine cannot move. Things like amplifier error states need not
really be dealt with here.
When power is turned on servo enable pins should be driven to true,
whatever logic direction that is.
You may need to add some troubleshooting steps to when power-on goes true
as some drives have errors that will need clearing, or other fun stuff. Do
it all here when the power-on goes high. It's a safe time to do it, it
makes sense for the drives to have a bit a few seconds of getting their
crap together if necessary at power-on. There is no requirement that the
machine go from power on to moving at 5m/s instantaneously. Once the
machine is in the power-on state, the state of your amp-ready signals will
start to be be taken into account by linuxcnc, so if an amp is in error,
you won't be moving anyways...
If you're setup this way, you can hit power-off/F2 (Escape is not quite
the same, canceled current event but does not go into power off) in the
event of some bad code, chips in your keyboard, or whatever else and all
your drive enables should drop and all motion stops, things become pretty
safe, but electrically everything still connected. You haven't lost
position/index counting, you haven't made anything unhappy by suddenly
disconnecting it from HV mains in the way E-stop might. And you can save
that big red E-stop button for the times you really need it, like in the
event of potential injury.
That's my 2 cents.
-Dave
On Sun, 27 Oct 2019 15:43:04 -0400, John Dammeyer <[email protected]>
wrote:
What exactly is the difference in LinuxCNC with the red ESTOP button and
the orange Machine ENABLE button?
MACH3 has only the RESET button which flashes when an ESTOP event like
limit switch or other error and results in power removed from the
drives. Spindle should stop. There's really no separate enable.
My feeling is the LinuxCNC Machine ENABLE button is separate from the
ESTOP button. Clicking the orange ENABLE button only prevents CNC motion
commands but isn't expected to remove Drive or System Power. That's
reserved for the ESTOP which also disables the Charge Pump.
Clicking the ESTOP button would then switch off the high voltage to
motors etc. and at the same time is also clears (switches off the
ENABLE). An ESTOP input would do the same. While ESTOP is active the
ENABLE button remains grey'd out and cannot be pressed to re-enable the
system . The ESTOP condition must first be removed.
But if all I do is click on the ENABLE button so it goes OFF then power
should remain on the system?
Have I got that right?
Thanks
John Dammeyer
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