Reply with QuoteIt loses position because there is a forced disconnect or power to the drives. The same will happen on most controls, steppers or servos.
Losing reference when ESTOP
Hi, i'm having some problems with my custom made machining center. It's has a nice precision of 0.008mm, built on grounded ballscrews and some other stuff.
But there is something that upset me, it's build around MACH 3 and has no feedback, it uses servos on their own closed loop system, but the controller has no feedback.
So about the thing... when i press the ESTOP button or i suddenly stop a program, my machine loses reference, not much, something like 0.2 or 0.1mm,
but for me it's a big ideal, i spent some real money on the construction, used some nice techniques to keep the precision and i want to make full use of it.
My theory is that when i press ESTOP, i stop MACH3, MACH3 then sends signals for the servos to stop, but this has some delay, maybe due to the controller board i'm using
or even the reaction time between COMPUTER, CONTROLLER BOARD, SERVO DRIVE and the MOTOR.
So now to the fix, i was thinking about physical linking the ESTOP button to the servo drive, it has so many functions, have anyone here done that ? I think it will improve reaction time.
Or anyone have another workaround ?
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Re: Losing reference when ESTOP
It loses position because there is a forced disconnect or power to the drives. The same will happen on most controls, steppers or servos.
Gary Campbell GCnC Control
Servo Control & ATC Retrofits
Re: Losing reference when ESTOP
You mean MACH3 cuts power from the drives? He can't do that i think. It just cuts the STEP signals sent right ? The drives don't know they're in a ESTOP mode, they're just waiting i think.
Re: Losing reference when ESTOP
imittheo,
You did not mention what you are using for a controller board, please post all pertinent details.
Jeff...
Patience and perseverance have a magical effect before which difficulties disappear and obstacles vanish.
Re: Losing reference when ESTOP
"You mean MACH3 cuts power from the drives? He can't do that i think."
Most systems I am used to will use a dual estop circuit to ensure drives are disabled during an estop event.
Gary Campbell GCnC Control
Servo Control & ATC Retrofits
Re: Losing reference when ESTOP
if the drives are moving when you press E stop, they will continue moving and slow down and stop as fast as the drive can do so... however the distance it takes the drive to slow down and stop moving would normally be accounted for by MACH3 and the drive would be commanded to slow down and stop. instead the drive is commanded to stop instantly and the distance you are measuring is the distance the drive took to slow down.
