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Messages - smurph

941
Galil / Re: Which Galil motion controller?
« on: January 07, 2011, 04:09:24 PM »
You don't necessarily need to control the spindle from the Galil.  It's just easiest to do so.  But what is required is an analog output to control the VFD.  So any device that has connectivity to Mach with an analog output can be used.  This could include any number of devices that have plugins or a ModBus capable device.  But then you will need to write brains to do some of the work amongst other configuration that make it a little bit complicated. 

So at ~$100.00 an axis on the Galil, it's actually pretty cheap.  An analog ModBus device would probably cost more.

One thing that can't be done (with any external motion plugin) is use the printer port.  So any printer port breakout boards that may have some spindle functionality just can't be used at all.

Steve

942
Galil / Re: Which Galil motion controller?
« on: January 07, 2011, 12:07:41 PM »
For the axes, you will want:
X, Y, Z, and a spindle.  That would be a 4 axis Galil controller.  Then, if you want an A rotary axis, add one for a total of 5.  And I would add another for your tool changer if you think that a servo will replace the existing tool changer motor for a total of 6 Galil axes.

It's important to remember that to control a spindle motor, not matter if it's a servo drive or a VFD drive, you will need a Galil axis for it.

Steve

943
Galil / Re: dro error after movement
« on: January 06, 2011, 12:45:50 PM »
No, I can't blame working late on this one.  Just a nut lose on the keyboard.  :)

944
Hmm...  You couldn't do a fine and a course, but you sure could move them together!  Geared to where the quill retracts and the knee drops to raise the Z and vise verse.  You could implement it all in the GalilInit.txt file that the plugin sends to the controller upon init.  This file should home the quill, home the knee, and then gear them together at a ratio where each reaches it's travel limit at the same time.  Brilliant Nosmo!  Mach and the plugin need not know a thing. 

GalilInit.txt file:  A file where, if it exists in the plugin directory, it's contents are sent to the Galil line by line upon plugin initialization (When Mach is started).

Steve

945
Galil / Re: Which Galil motion controller?
« on: January 05, 2011, 10:35:17 PM »
Galil is a great supplier of these.  :)  http://www.galilmc.com  They have the pricing on their site.  If you get one from eBay, do your homework.  Some of the controllers on eBay are OEM spec controllers that Galil made for many different machine companies.  These can get quite custom and you may not get what you think you are getting.  And Galil will NOT support them.  For instance, I have seen a 5 axis controller with ABCD and F (skipping the E axis).  And I have also seen controllers with custom firmware that is so specialized that it will not work with the regular Galil command set.  So be careful.

The good deal days are gone on eBay.  Most of the time, you can get a brand new 41x3 controller for less money than people want for the older Optima controllers on eBay.  Becuase the Optima controllers used a very special and expensive interface cable that you just have to have and then you will also need an ICM2900 (Breakout board) to go along with it.  The new 41x3 econo controllers make use of cheap DB style connectors making it relatively easy to roll your own cables.

Every now and then there might be a good deal on eBay.  But it's always a risk.  

Don't just look at controller prices.  Make sure you account for everything that is needed.  

Steve

946
Galil / Re: Which Galil motion controller?
« on: January 05, 2011, 09:58:10 PM »
Good controllers are the DMC-21x3 and DMC-41x3 econo controllers.  However, if you need lots of I/O, then one of the DMC-40x0 controllers may be the ticket.  Or, you can run an econ0 controller for your motion and use another device (such as the CONTEC PIO cards) for I/O.  I have a plugin for the Mesa Anything I/O 5i20 cards that will provide 72 bits of I/O as well.

Steve

947
Galil / Re: dro error after movement
« on: January 05, 2011, 05:31:52 PM »
To change the PID values on the Galil, use the KP, KI, KD commands.

KPA? will give you the current value of P for the Galil A(X) axis.

KPA=x.********* will change the P for for the Galil A(X) axis.

BV saves the values to NVRAM.

948
Galil / Re: dro error after movement
« on: January 05, 2011, 02:55:46 AM »
Mach will not move until it hits the numbers, but the Galil will try to.  The loop is closed on the Galil.  Mach simply reports the position. 

But you problem looks like friction to me.  PID tweak time!  I bet if you decoupled the servo from the screw, the motor would move to right numbers.  Try bumping up the proportional gain (P) and see what happens.  If you start overshooting the numbers and walking back to them, decrease the P until you get a happy medium or you might have to bump the D ever so slightly (I mean just breath on it).  If you get to a point where you hit your numbers but get unstable where it should be holding, bump up the I.

Steve

949
Yes, a post processor for the post processor.  :)  But...  in order to do that, you will have to set the top of the part (Z = 0) with your quill in the fully retracted position.  Otherwise, how will your knee movement computations know that there is less than 3.5" of travel available on the quill.  And then you might want to fudge a bit, say .200", for a rapid plane.

Steve

950
Rob,

Yes, he can assign his second Z axis to A in Mach.  But he wants to have his CAM software output XYZ moves and Mach to take the Z moves and split them up into A (knee: Z moves > 3.5" rough position) and Z (quill: Z move < 3.5" fine position) on the fly.  Unfortunately, that is not possible.

Steve