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### Author Topic: What's the best way to determine motor velocity?  (Read 15004 times)

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#### Brian Barker

• 3,854
##### Re: What's the best way to determine motor velocity?
« Reply #20 on: April 26, 2006, 07:53:15 PM »
I was thinking DRO and typed LED Sorry about that... it needs to be an DRO for the Max F that you would like to have.
« Last Edit: April 26, 2006, 09:45:04 PM by Barker806 »
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#### sshneider

• 401
##### Re: What's the best way to determine motor velocity?
« Reply #21 on: April 26, 2006, 09:22:09 PM »
Hey,

OK, Well I put a LED there.  What's next?  How do we tie it into a user defined parameter?

Thanks,
Sid

#### sshneider

• 401
##### Re: What's the best way to determine motor velocity?
« Reply #22 on: April 28, 2006, 09:11:11 AM »
bump

#### Brian Barker

• 3,854
##### Re: What's the best way to determine motor velocity?
« Reply #23 on: April 28, 2006, 07:43:44 PM »
Here is a quick Macro

'If the FRO rate is over the Max set the FRO % to the right val
FMax = GetOEMDRO(1200)
If (FMax = 0) Then
Exit Sub
End if
FRO = GetOEMDRO(55)
If(FRO > FMax) Then
Value = FRO / (GetDRO(21)/100)
NewFRO = (FMax / Value) * 100
Call SetDRO(21,NewFRO)
End If

And I changed the screen set too...

That should get you going
Fixing problems one post at a time

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#### sshneider

• 401
##### Re: What's the best way to determine motor velocity?
« Reply #24 on: April 28, 2006, 08:53:23 PM »
THANK YOU BRIAN!  It's Awesome!

Regards,
Sid

#### jpeter

• 24
##### Re: What's the best way to determine motor velocity?
« Reply #25 on: May 03, 2006, 05:38:38 PM »
In my case its the rapid that takes it over the top. Wouldn't it be nice if the FRO only affected feed rates below the max. For example, I decide because of a light cut I can up the rate so I F11 the FRO. Now in a rapid my z is skipping steps. I hate that.

Jim

#### sshneider

• 401
##### Re: What's the best way to determine motor velocity?
« Reply #26 on: May 03, 2006, 08:15:37 PM »
Jim,

I don't get it.  Isn't Rapid always the same or does the FRO effect rapid also- I never really noticed that.

Sid

#### Brian Barker

• 3,854
##### Re: What's the best way to determine motor velocity?
« Reply #27 on: May 03, 2006, 09:12:25 PM »
it will not make the rapids faster but under 100% FRO will slow them down..
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#### jpeter

• 24
##### Re: What's the best way to determine motor velocity?
« Reply #28 on: May 04, 2006, 02:32:46 PM »
I may be wrong about the rapids but here's my situation. My mill will slide at any speed I program. If the speed's  over the maximum the slide goes to its max and continues to move. But, if I FRO above 180 percent  no matter what speed's been programed I skip steps. I assumed it was skipping during the rapids because they're the fastest, most of the time.

Something I need to set differently?

Thanks,

jim

#### sshneider

• 401
##### Re: What's the best way to determine motor velocity?
« Reply #29 on: May 04, 2006, 03:21:28 PM »
Jim,

I'm not sure if you need to set something differently.  To be honest the whole issue of feed rates and motor tuning is a tad bit mind boggling to me.  I think this is due to the fact that some basic principals need to be established in order for me to understand exactly what is going on.

That being said, either I need to just play around with my machine here and have a little 'discovery' time or perhaps Mr. Barker (or others) could help to clarify.

1.  My Impression is that on the motor tuning screen that the Velocity represents the MAXIMUM VELOCITY THE MOTORS WILL TURN ON A RAPID G0 command.  MAXIMUM meaning that regardless of how high you set your FRO that the motors will never turn faster than this.

2.  If #1 is true then if one sets the max velocity on the motor tuning screen and does not miss steps, it should never be possible to miss steps during the course of a cut (unless the cutter is being restricted from moving but, this is another issue and not related to trying to run the motors too fast

If #1 is NOT true, then measures need to be taken to insure that #1 IS, in fact, true.  I would venture to guess that the measures one would take would be.... BEFORE you go to your motor tuning screen, set your FRO at the MAX (I think it's 290%).  Then do your motor tuning/set your max velocity

So, which is it gang?  Is #1 true or not?

Thanks!

Sid