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Author Topic: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105  (Read 11396 times)

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Re: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105
« Reply #10 on: November 30, 2013, 03:49:18 PM »
Steve sorry for juming to another topic. Using chance to have your attention. is tere way to connect ethernet controller say 2260 directly to PC ethernet port? At the moment connected over local net through router but want to install all in one box and router kinda look alien >:D in it.

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Re: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105
« Reply #11 on: December 01, 2013, 06:12:29 PM »
I just showed a sample of the output stream, not the whole stream.  The IT command is used for independent axis moves.  VT is used on vector moves on earlier controllers.  For later Accelera controllers, VT has been removed and IT provides the smoothing for both independent and vector moves.   That particular data stream came from a 2173 controller.  VT is correct for it.  This VT/IT parameter is a setting in the plugin.  You can make the machine act how you want with it.  The PID filters and VT/IT will smooth things out, or not.  Your choice.  I prefer to just run the profile as output by Mach.  It's granular enough as to not make huge "stair steps".  And besides, steppers use it all of the time.  That is the output you get out of Mach.  Mach sends data points, way points, dot plots, whatever you want to call them.  They describe the movement.  Mach does not send down CR, PR, or PA like information.  In the Galil plugin, we take the incremental way point information from Mach and stuff them into a LI command (or CD command for contour mode).

As for your pictures, you will never get the first curve as output from Mach (input to the controller).  There are no points to describe the spline!  There is a time period between each point in the dot plot and this is a parameter that is settable by the plugin.  This will determine the granularity of the system.  If I tell Mach that I want way points on 1ms intervals, then the resulting dot plot is going to be really smooth to begin with.  No smoothing required.  Conversely, if I told Mach to output 32ms interval way point, then the dot plot it is going to be a lot rougher.  A low granular system will benefit most from smoothing functions.  However, it can't be as accurate.  

With the smoothing functions, it may be possible to get the machine to move like the fist curve picture.  But again, the points in each picture are the same!  The data points simply do not adequately describe the curve in the first picture.  If that plot is say 4ms between the points, then decreasing the time interval to 1ms is going to describe the curve with 4 times the data points and result in smoother motion.

This has nothing to do with closing the motion loop.  It has everything to do with what kind of input the controller gets from Mach.  If the controller is in LI mode, sending more LI commands with data points for the same move will yield a smoother profile.  Generally, sending LI commands that represent 4ms of movement is sufficient.  You get nice round circles with that.  At least to the point where you really can't measure the faceting that all non linear moves have.  8ms is ok, but depending on the feed speed, faceting may be more than desired.

LI mode will "interpolate" between the points.  How it does that depends on the other settings (IT or VT and VD/VA).  Meaning, you can let the Galil motion profiler have some influence, if desired.  Those VT, VD, VA values in that stream sample effectively turn the Galil profiler off.  It is possible to smooth things too much and lose accuracy.  It is also possible to "tune" the system to get awesome results.  Leaving the default plugin parameters as they are yield very acceptable results.  But tweaking them may yield better results depending on your machine.

CD mode will follow the dot plot precisely with no smoothing between the points.  Accuracy is stellar.  This is basically position over time, or PT.  Like a stepper system.  No "tuning" required (PID still needs to be tuned though!).  This is the mode I would specify if the controller can do it and you have a fairly granular system as far as counts/unit and time interval is concerned and you don't want to play oscilloscope for hours on end searching for the "perfect" tune.  I have run this mode on a highly rigid motion system (gear drive instead of belt on my Matsuura) with 2ms time slices and 12700 counts/inch and it is just plain awesome.

Which mode you use is up to the controller you have and/or your preference.  

There is a new position and velocity over time (PVT) mode on the Accelera controllers that I will leverage for Mach4.

All of this is entirely dependent on the machine as a whole system.  If you have a wet noodle sloppy motion system, you are not going to have good results no matter what features of the Galil you use.  

If you still don't get it, then I would suggest getting a Galil and trying it out.  The Galil is a high quality motion controller.  The Acceleras are insanely fast (22MHz encoder inputs) which allows for insanely granular counts per unit on the encoders and still get high traverse speeds.  In my opinion, pair a Galil with a good machine and Mach and NOTHING will be better.  And it is the only motion controller that allows mixing of servos and steppers that I know of.

Steve
« Last Edit: December 01, 2013, 06:15:37 PM by smurph »
Re: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105
« Reply #12 on: December 02, 2013, 05:13:08 AM »
Steve
Thanks again I got all picture now :-)
At the moment (for last 5 years) been using Mach3 on my Baby ( picture below ) kinda wet noodle - metal case granite/polyfill L-frame THK KR33's Mitsu Servos in position mode (dynamic autotune PVT) from parallel ports.  Deflection on tool end (NSK 320) X- axis force @ 100N 0.05mm. Cutting wax for jewellery all code look like this   
(Rotate Table Operation)
Code: [Select]
(Rotate Table Operation)
Z36.0000
X0.0000 Y0.0000
A+90. F1200.
(Horizontal Roughing)
Z3.7561
X0.9967 Y-2.4577
G01 Z3.3150 F1000.0
Z2.6800 F500.0
X0.5038 Y-1.8557 F1000.0
X0.5040 Y-2.4696
X0.9967 Y-2.4577
X1.0027 Y-2.7077
X0.2541 Y-2.7257
X0.2532 Y-0.0293
X0.6727 Y-1.6674
X1.5144 Y-2.6954
X1.0027 Y-2.7077
X1.0087 Y-2.9576
X2.0447 Y-2.9327
X0.9149 Y-1.6054

...
As you would know this will give choppy sort of cutting pattern (machine bolted to the table) intelligent smoothing with analysis were small axis direction change will apply max smoothing and 45 degree or sharper will take smoothing to min and ramp down velocity proportionally on approach - would be kinda nice to have. 
Saying this I have tried to make NC code with this kinda behavior it work really good but configuring CAM post processor to this pattern sometime mess things up! 
This was reason I start  looking for more intelligent motion controller 
I do have GALIL DMC-2260 (Acellera's expensive) to play with and putting wiring together at the moment to see how is gonna perform on similar setup.
Thanks for help again I found important to know how this thigs work before building new system.
It be helpfill to have Mach  NC to galil code library this would show how you implement plugin translation. Thanks
Ilia

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Re: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105
« Reply #13 on: December 02, 2013, 02:19:48 PM »
The DMC-2260 is a good controller.  It has 100 Mb Ethernet and can probably do 2ms in LI mode pretty well.  Tweaking the VA, VD, and VT params via the plugin will smooth things out even more.  I have never tried the position control (step/dir) input servo drives, as there is really no reason to use a Galil with them.  So for your machine, I would suggest 200w analog command servos.  A bit overkill, but you can soften them up with the PID parameters.  You will most likely want to drive the screw with a reduction belt drive to the servo.  No direct drive as often used with steppers.  Most servos will do 3K RPM so gear reduction is the norm. The more encoder counts per unit you can get is going to help all things out.  The Galil will handle 50,000 counts per inch easily.  So use 5:1/4:1 reduction or so on the servo to the screw and then calc in the screw pitch to get in the 30,000 to 50,000 counts per inch ball park, assuming 1024 counts per rev or more encoders on the servos.  Adjust accordingly for metric.

I like the little Yaskawa SDG/A servo drives and the matching SGM motors.  Bullet proof.  And you can find them pretty cheap on eBay.  SDGA-02BS is the 100v (110v mains) drive and the SDGA-02AS is the 200v (220v mains) drive.  The motors have to match the drive voltage.  For smaller 100 watt system, SDGA-01BS or SDGA-01AS.  Big thing here is getting the cables control cables with the drives.  Or at least the stubs.  Otherwise, you will have to order some expensive cables!

The 200 watt motors are not much bigger than NEMA 23 steppers.  The 100 watt motors are even smaller.

Tuning the servo system is a royal pain.  But once done, it is well worth it, IMHO.  Quiet and smooth.  Less stress while operating the machine.  The sound is rather nice on the ears.

Be careful though...  Once you go servo, you never go back!  :)
Re: Mitsubishi J2S-40A and Galil DMC-2183 with ICM-20105
« Reply #14 on: December 10, 2013, 10:17:26 AM »
Steve Thanks for help one moore.  (actually were two but one kinda hidden :-)
One careful question from warned man - Im not to sure about gearing motor to ball screw as pitch 6mm per turn THL LM slides and ballscrew allow speeds upto 500mm/sec (this is fast) motor should do 5000rpm then but with encoder count 131072pulce/revolution we getting a lot of pulses per Inch 554,871 pulses in straight 1;1 and 1;4 = 2,219,485 per Inch do you think is kinda feasible?

Then I connect Mitsu's in my maschine (photo above) in position mode I used electronic gearing in Mitsus drive in order to compensate missing frequency from Mach.

Don know how to deal with this issue with Galil + Mach combo??  ( Galil DMC-2260 can handle twice as manypulses @ given speed but how many Mach can comand? )

Ilia

P.S. How you add time delay on AMP ENeble  is were WT somere but I dont see? 
( For safe Mitsu need like 2 sec after powerON WT 2000. )