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Author Topic: AC Servo Spindle and ESS  (Read 6211 times)

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Offline Jeff_Birt

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Re: AC Servo Spindle and ESS
« Reply #10 on: April 14, 2015, 11:03:42 AM »
True, I did not think of that. Then the custom start button would need to fed hold and turn off the spindle. Still you will have the same undesirable action with EStop so a electromagnetic brake may be the only way to go.
Happy machining , Jeff Birt
 
Re: AC Servo Spindle and ESS
« Reply #11 on: April 14, 2015, 12:31:27 PM »
Thanks Dan.

You might also utilize/incorporate the drives enable input to any macro or button script you might make up.
An instant disable would allow the servo to coast to a stop on some drives .... if not all most likely. Yours may however be different.

The E-Stop should of course stop instantly.

Russ
« Last Edit: April 14, 2015, 12:52:25 PM by Overloaded »

Offline Dan13

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Re: AC Servo Spindle and ESS
« Reply #12 on: April 14, 2015, 03:23:53 PM »
Using the latest ESS plugin with 062 Mach version.

I don't have a problem with the Estop as it sends a command directly to the Serrvo emegency stop input. The servo then coasts to a stop. Like I said, I can send a signal over modbus to the servo emergency input on a Stop hit. Wonder if Mach allows to trigger a signal on a reset hit as well.

Dan

Offline Jeff_Birt

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Re: AC Servo Spindle and ESS
« Reply #13 on: April 14, 2015, 04:20:50 PM »
Quote
I don't have a problem with the Estop as it sends a command directly to the Servo emergency stop input

That describes an enable line not an EStop. An EStop generally removes power immediately from all things that move. That means when you hit the EStop button the mains to the servo power supply should be cut. If you are relying on a logic input to the servo drive what do you do when the servo encoder dies and the servo runs away?

There are some types of machine that will let servo controlled axis coast for a few seconds in order to safely decelerate them and then cut power. Different regulating bodies will have different codes that cover this sort of thing.
Happy machining , Jeff Birt
 
Re: AC Servo Spindle and ESS
« Reply #14 on: April 14, 2015, 07:34:26 PM »
That is why he needs the macro, to issue the feedhold then the stop after the speed is down low enough.

Offline BR549

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Re: AC Servo Spindle and ESS
« Reply #15 on: April 14, 2015, 09:15:43 PM »
Stop should do no harm to machine or OP. I do not know of ANY commercial controllers that do not deaccellerate the spindle and axis's on STOP.  If it is an emergency STOP then Estop is the proper proceedure and that is stop at all cost even using the crowbar method .

STOP is NOT an Estop.

Just a thought, (;-) TP

Offline Dan13

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Re: AC Servo Spindle and ESS
« Reply #16 on: April 15, 2015, 02:37:14 AM »
Jeff, I neglected to mention that hitting the Estop also cuts power to all drives.

Dan

Offline Hood

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Re: AC Servo Spindle and ESS
« Reply #17 on: April 15, 2015, 06:50:07 AM »
It all boils down to the fact there is an issue with the ESS and the spindle, not sure if it is solely Step/Dir spindles or whether it is all control means.

The ESS should not suddenly take away the pulses from the spindle when you press Stop, the USB SS does not do that (although it used to) and any other controller I have used does not.

As said earlier I have now got into the habit of first pressing the Spindle Off button, after the feedhold and before I press Stop, but I do occasionally forget and it is not pretty with a heavy chuck.

Hood
« Last Edit: April 15, 2015, 06:52:04 AM by Hood »

Offline Jeff_Birt

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Re: AC Servo Spindle and ESS
« Reply #18 on: April 15, 2015, 07:27:59 AM »
Hood, the default behavior for Mach 3 is to stop all pulses when Stop is pressed. The ESS is simply doing what the parallel port driver has always done, not that it is a good thing to do. Think about it this way, what path should an axis decelerate in? The ESS has no idea, only Mach 3 knows the path that was programmed via GCode. The only thing the ESS could do is decelerate each axis in a straight line.
Happy machining , Jeff Birt
 

Offline Dan13

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Re: AC Servo Spindle and ESS
« Reply #19 on: April 15, 2015, 07:31:17 AM »
Right Hood. And as Terry said hitting a stop on a machine should not harm it. There is a problem with the ESS and everything else are just workarounds.

Dan