Ramp out step/dir servo spindle

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19 Oct 2020 13:52 #186583 by jazial
Hello,

I'm trying to set up a spindle on a mill using a step/dir servo

I've managed to make it ramp in, using but i'm not sure the way to ramp out

Ideally I want M5 to ramp out, waiting for the spindle to deactivate stepgen.
As i need rigid tapping too, it's very confusing for me at this time

Background :
The machine I'm working on was retrofitted with linuxcnc 5 years ago (3 DC servos on axes, 1 three phase servo on spindle, +/- 10 signal for all), and everything goes well till summer 2020 when one DC driver fried both 7i77 and itself and 3 phases driver seems like to be near to death

I've changed every motors and drivers for AC 3 phases servos, tried to make them working with +/- 10v, and then figured that 7i77 didn't count anymore on some encoders inputs (worse, moving MPG on encoder 02 increased encoder 00 counts, so really hard to tune the system)

As I had a 7i76 laying around, I'm trying to redo my config with step/dir signals
I've added a 7i85s to read encoders, but closing loop is not done at this time on axes, I'm just trying to complete it on spindle first.


Thanks

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20 Oct 2020 00:33 - 20 Oct 2020 00:36 #186640 by pippin88
Yes, you need to delay disabling the stepgen output until after spindle has slowed down.

Two ways:
Time delay
Wait until spindle rpm reaches certain level (near 0rpm)

I am currently using a simple time delay:

hal:
####  only code relevant to spindle ramp shown

# --- Spindle accel / decel --- #

loadrt limit3
addf limit3.0 		servo-thread

setp limit3.0.maxv 	[SPINDLE_9]SPINDLE_RAMP
setp limit3.0.enable 	true

net spindle-vel-cmd-rps 	=> 	limit3.0.in
net spindle-output 		<= 	limit3.0.out

net spindle-output     => 	hm2_7i43.0.stepgen.04.velocity-cmd

# --- timedelay before disable spindle output for deceleration ramp --- #
loadrt timedelay 	names=timedelay.spindle-enable-soft-stop
addf 			timedelay.spindle-enable-soft-stop    servo-thread

setp timedelay.spindle-enable-soft-stop.on-delay 	 	[SPINDLE_9]ON_DELAY
setp timedelay.spindle-enable-soft-stop.off-delay 	 	[SPINDLE_9]OFF_DELAY

net spindle-enable          	=> 	timedelay.spindle-enable-soft-stop.in
net spindle-enable-soft-stop	<= 	timedelay.spindle-enable-soft-stop.out
net spindle-enable-soft-stop	=> 	hm2_7i43.0.7i76.0.0.output-09 hm2_7i43.0.stepgen.04.enable


ini:
#********************
# Spindle 
#********************

#only code relevant to spindle ramp shown

SPINDLE_RAMP = 20
ON_DELAY = 0
OFF_DELAY = 5
Last edit: 20 Oct 2020 00:36 by pippin88.
The following user(s) said Thank You: partec, jazial

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