Ramp out step/dir servo spindle

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6 years 1 week ago #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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6 years 1 week ago #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:
Code:
#### 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:
Code:
#******************** # Spindle #******************** #only code relevant to spindle ramp shown SPINDLE_RAMP = 20 ON_DELAY = 0 OFF_DELAY = 5

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