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VMC related HAL questions.

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08 Jun 2015 02:10 - 08 Jun 2015 02:10 #59603 by thewho
Replied by thewho on topic VMC related HAL questions.

When you say there is no speed command, where are you looking?

I'm not looking at any pins, the fact that I can stop the spindle with a light touch tells me that there probably is no speed output.

The screenshot shows a pid.0.output of 325.1263.
Now that I think of it, the pid might might work correctly. If the speed command the pid.0 gets is wrong. The x6 speed problem I still have.

Is it line 11 I should edit?
net spindle-vel-cmd 		motion.spindle-speed-out pid.0.command
To this?
net spindle-vel-cmd 		motion.spindle-speed-out-rps pid.0.command

Can I write the tolerance like this?
setp orient.0.tolerance [SPINDLE]ORIENT_TOLERANCE
And then add this line to the ini.
ORIENT_TOLERANCE = (number)
Last edit: 08 Jun 2015 02:10 by thewho.

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08 Jun 2015 02:13 #59604 by andypugh
Replied by andypugh on topic VMC related HAL questions.

When you say there is no speed command, where are you looking?

I'm not looking at any pins, the fact that I can stop the spindle with a light touch tells me that there probably is no speed output.

Are you talking about position mode or velocity mode here?

The screenshot shows a pid.0.output of 325.1263.

But orient mode should be using pid.1. You need to see what that one is doing to get orient to work.

Is it line 11 I should edit?

net spindle-vel-cmd 		motion.spindle-speed-out pid.0.command
To this?
net spindle-vel-cmd 		motion.spindle-speed-out-rps pid.0.command

Can I write the tolerance like this?
setp orient.0.tolerance [SPINDLE]ORIENT_TOLERANCE
And then add this line to the ini.
ORIENT_TOLERANCE = (number)


Yes to all the above.

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08 Jun 2015 03:19 #59608 by thewho
Replied by thewho on topic VMC related HAL questions.
1. position
2. velocity (M3 S60)

I don't know when I can try anything on the machine next time, probably next weekend though :angry:

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08 Jun 2015 03:24 #59609 by andypugh
Replied by andypugh on topic VMC related HAL questions.

I don't know when I can try anything on the machine next time, probably next weekend though :angry:


Sorry not to have been more help. I really don't understand why this is being so difficult.

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08 Jun 2015 20:59 #59627 by thewho
Replied by thewho on topic VMC related HAL questions.
Yay I could escape work a bit earlier today and try out some things. :)

I changed the line to this:
net spindle-vel-cmd-rps 		motion.spindle-speed-out-rps pid.0.command

And it seems to work :blink:
I also think that orient works when I gave it some room to play (2deg)
Tuning it seems to be really fun if you want it semi fast. Gear driven head with a bit of play in the gears doesn't help.. :dry:

It takes ages for the spindle to slow down from full speed (M3 S5000 > M5) so I was thinking of wiring up the "quickstop" aka. brake input on the spindle drive. But that might solve it self when I get the tool changer to work as it has to orient before the arm moves?

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09 Jun 2015 00:03 #59632 by andypugh
Replied by andypugh on topic VMC related HAL questions.

Yay I could escape work a bit earlier today and try out some things.

Whereas my employer has suddenly blocked linuxcnc.org so I can't check the forums at lunch time any more.

It takes ages for the spindle to slow down from full speed (M3 S5000 > M5) so I was thinking of wiring up the "quickstop" aka. brake input on the spindle drive. But that might solve it self when I get the tool changer to work as it has to orient before the arm moves?

You might be able to alter VFD parameters to get a faster response.

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09 Jun 2015 01:29 #59636 by thewho
Replied by thewho on topic VMC related HAL questions.
Oh man that sucks!
I haven't found any setting for that. When spindle enable is 0 the drive cuts all power to the motor and it freewheels to a stop.

I did some test cuts tonight and the speed compensation that pid gives is awesome! Motor current peaked at 25A :lol:
Rigid tapping seems to be working good to. Haven't tried tapping anything yet though.

Orient is a bit funny still, reacts very fast but when within 5º it slows down to a crawl and sometimes it times out even at 20sec.
Will a bit of "i" help with that? Forgot to try it when I was there.

Moved the atc arm by hand and found out that "orient" need to be enabled when the arm moves out because it sometimes touches the tool and rotate the spindle enough that the tool doesn't seat right in the carousel pocket.
Any thoughts how one would do that?

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09 Jun 2015 01:51 #59637 by andypugh
Replied by andypugh on topic VMC related HAL questions.

Oh man that sucks!
I haven't found any setting for that. When spindle enable is 0 the drive cuts all power to the motor and it freewheels to a stop.

In orient mode the spindle won't disable the VFD though, it will always provide an output, and possibly a reverse one.

Orient is a bit funny still, reacts very fast but when within 5º it slows down to a crawl and sometimes it times out even at 20sec.
Will a bit of "i" help with that? Forgot to try it when I was there.

I would expect to need some I, and maybe even a bit of D.
It's a good thing to practice PID tuning on as a runaway isn't a big deal.

Moved the atc arm by hand and found out that "orient" need to be enabled when the arm moves out because it sometimes touches the tool and rotate the spindle enough that the tool doesn't seat right in the carousel pocket.
Any thoughts how one would do that?

If you have a spindle lock or brake then you could enable that. There is even a motion.spindle-locked pin that could be used to operate it.
www.linuxcnc.org/docs/html/man/man9/motion.9.html

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12 Jun 2015 01:35 #59715 by thewho
Replied by thewho on topic VMC related HAL questions.
How well does orient do on a quality vfd? Or an Huanyang (or whatever the name is) for that matter?
Pondering on a small(ish) lathe where I need positioning for drilling off center holes. Yes, there will be a brake on the spindle.
There is no need for super precision but I would like it to be rather good.

If that's not good enough I'll have to add a stepper somewhere :whistle:

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12 Jun 2015 03:26 #59725 by andypugh
Replied by andypugh on topic VMC related HAL questions.

How well does orient do on a quality vfd? Or an Huanyang (or whatever the name is) for that matter?


The only example I have is on a lathe with a very old VFD and rather a direct drive, and I think that the result would disappoint you.

I have seen it work well with a good encoder and a flux-vector drive. But without details of how well you need it to work it is hard to advise.

You could consider using a large servo motor as the lathe spindle motor.

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