Another "what do I need" thread. Vmc retrofit

andypugh
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03 May 2015 00:14 #58332 by andypugh

Replied by andypugh on topic Another "what do I need" thread. Vmc retrofit

thewho wrote:
No not now when I changed the spindle enable as PCW said.
But 0.1V is still 50rpm off target so it's nice to get rid of that.

The spindle orient example that I linked to earlier included closed-loop spindle speed control. That will get the speed spot-on

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thewho
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03 May 2015 00:35 - 03 May 2015 00:38 #58333 by thewho

Replied by thewho on topic Another "what do I need" thread. Vmc retrofit

Got it down to 18mV measured on the spindle drive :lol:

One thing about the spindle enable:
When I run the spindle and then stop it (M5) the output is immediately turned off making the spindle coasts to a stop. And from 5krpm it takes its time :whistle:

So is it possible to add a delay to M5 so that the spindle has time to brake before it's disabled?

In other words:
-M5 is called
-Analog output = 0V
-Wait 2seconds
-Disable "spindle enable" output

Edit: Didn't see your post Andy
I looked at the link and picture but as usual I didn't understand what I was looking at

Last edit: 03 May 2015 00:38 by thewho.

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andypugh
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03 May 2015 00:40 #58334 by andypugh

Replied by andypugh on topic Another "what do I need" thread. Vmc retrofit

thewho wrote:
When I run the spindle and then stop it (M5) the output is immediately turned off making the spindle coasts to a stop.

This might be configurable in the drive.

So is it possible to add a delay to M5 so that the spindle has time to brake before it's disabled?

As usual, the answer is "of course" :-)

www.linuxcnc.org/docs/html/man/man9/timedelay.9.html

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PCW
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03 May 2015 00:56 #58335 by PCW

Replied by PCW on topic Another "what do I need" thread. Vmc retrofit

You could also use the "near" component and disable the spindle only when
the measured spindle RPM was near 0, so you don't wait longer than is required
to come to a stop.

(this need gating with machine-on of course)

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thewho
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03 May 2015 04:33 #58340 by thewho

Replied by thewho on topic Another "what do I need" thread. Vmc retrofit

I'm very thankful for all help I'm getting here

Problem is that I still don't understand hal files enough to edit/write them :unsure:

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thewho
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03 May 2015 21:17 #58352 by thewho

Replied by thewho on topic Another "what do I need" thread. Vmc retrofit

Well.. The machine made some chips today. Not without problems though

Rpm and actual rpm differs a bit but that is the spindle drives fault. (easy fix)
The spindle drive compensates for load but nowhere near fast enough so for lower rpm's closed loop spindle control is required.
That is a 63mm 45º face mill running 300rpm and 0.1mm/tooth. Approx 75% woc and 2mm doc.

I gave up after that and went home..

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andypugh
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13 May 2015 07:49 #58615 by andypugh

Replied by andypugh on topic Another "what do I need" thread. Vmc retrofit

This thread seems to have gone rather quiet.
To see how well my new comps work I have been making a simulated VMC to test them with. It's cheaper that way when things go wrong.

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cmorley
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13 May 2015 09:20 #58616 by cmorley

Replied by cmorley on topic Another "what do I need" thread. Vmc retrofit

Very cool Andy...will you add that simulation to linuxcnc repo?
Do you have notes how you simulated the VMC ?
The visualisation program would be so more helpful with docs - as I'm sure you discovered

Chris M

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BigJohnT
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13 May 2015 18:34 #58628 by BigJohnT

Replied by BigJohnT on topic Another "what do I need" thread. Vmc retrofit

thewho wrote:
I'm very thankful for all help I'm getting here Problem is that I still don't understand hal files enough to edit/write them

Hal is a very simple language with only a few commands. A good place to start understanding is the Basic Hal Tutorial .

JT

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andypugh
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13 May 2015 22:31 #58640 by andypugh

Replied by andypugh on topic Another "what do I need" thread. Vmc retrofit

cmorley wrote:
Very cool Andy...will you add that simulation to linuxcnc repo?
Do you have notes how you simulated the VMC ?
The visualisation program would be so more helpful with docs - as I'm sure you discovered

I am not certain that I understand the code well enough to document it. I just messed about until it worked.

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