Messages

1

Galil / Re: Problems with losing position

« on: March 19, 2014, 11:32:06 AM »

Follow up, cut a sign that takes 1/2 hour each last night on 3 different boards, they were all spot on, to the .001 of each other.  This sign in the past would get off from 1/8" to 1/4" over the length of the sign, cutting this same g-code successfully proves the open ground caused this problem.  If you have a position issue, I definitely recommend checking your grounds and use shielded cables with the shields grounded.

Matt

2

Galil / Re: Problems with losing position

« on: March 18, 2014, 10:42:05 AM »

The electrical engineer also said be sure to only ground your encoder shield on the controller side not the motor side.  Just leave the aux encoder shield loose on the motor side.  Mine was already this way, but maybe that will help somebody in the future.

Matt

3

Galil / Re: Problems with losing position

« on: March 18, 2014, 10:39:33 AM »

Steve,

I finished rebuilding my Y axis to be identical to the X, same counts per inch, brackets, etc..  The problem of losing position (thru DMC Smart Terminal) got worse and more erratic!  An electrical engineer I consulted with said he has seen this when there is a floating ground.  SO I plugged in an extension cord and took an Ohm meter from that ground to the motor body, router, frame, etc, all seemed well grounded.  The cable shields connection to my 100 pin break out box were also grounded.  The problem was the cable going from the 100 pin break out to the amps was shielded but not grounded, I grounded that reran the test in DMC terminal cutting the same hole 70 times and the size only grew .001.  Next in Mach3 programmed a a loop to cut a hole measured it, then put it in a loop to cut the hole 50x, again only grew .001. So the ultimate issue was a floating ground.

For somebody in the same boat of losing position here is a list of things I did when trying to fix this problem.
>Try a test cut in DMC ST or Galil Tools  (Problem showed there when I increased AC and SP, which rules out a Mach3 setup). Be sure that you have your Galil setup properly good PID, AC, DC etc and BN.
> Replaced all the cables with shielded and grounded cables.
> Formatted and rebuilt my PC. (probably should have been the last thing I tried, the PC does not have much effect on a Galil)
> Checked and rebuilt my mechanical drive to make it as good as possible.
> Tested the ground of all components.  (Found the shield on the cable going to the amps was not grounded, this caused my position loss issue).

All is well now, now I get to cut some cool stuff, can't wait!!
Thank you so much!
Matt

4

Galil / Re: Problems with losing position

« on: March 03, 2014, 10:51:22 AM »

Follow up, that may help somebody else following this thread.  With this new plugin I was cutting a small circle .400 with 1/4EM, then moving off 5" in Y to change the part then repeating many times (x100), I found I was losing location in Y.  Knowing Galil pretty well I carefully reviewed the Galil plugin log and saw no cause for the drift.  I then recreated the arc program in DMC language and ran it in DMC smart terminal (ST), it did drift in Y although a factor of 10 less over the same number of cycles, but still not right.  Neither Mach or ST ever drifted in X, even when I made the 5" move in X.  I think this proves what Steve originally suspected that I must have something mechanically wrong with my CNC.  Over the weekend I took Y completely apart and did find a point of slip, I am fixing that.  Thank you Steve!  

Any thoughts why the mechanical would cause a greater position loss in Mach3 than it would in ST...  Hmmm as I write this I think the difference could be the motion profile dynamics are different in Mach3 than they are in ST, so it makes sense that the mechanical flaw would show it self differently.  To show a flaw in ST you need to push the motion profile harder with more complex moves, this is why I did not originally see the problem.  It is like a car with a mechanical flaw may not show when a Granny (ST) drives it, but will show when a race car (Mach) driver drives it.  You can push ST harder with greater AC SP and more moves, you just have to do that in testing like this.  I could have saved myself some time by pushing things harder in ST.  I learned something here.

Also while I am redoing things I am changing the gear ratio of Y to match X.  I advise somebody building a machine to do this because it makes it much easier to use ST to test (or use for production in a pinch) since you can not easily have a different pulses per inch in ST like you can in Mach3.

Matt

5

Galil / Re: Problems with losing position

« on: February 13, 2014, 10:02:29 AM »

Hi Smurph,

I know what you mean about the Bus controller handling the DR differently, I had to come to a similar conclusion.  Dropping support for them is the right decision because the way you have to process the DR on a BUS controller is so much slower than the old methods of retrieving records that it really handicaps those controllers.  So even if you took the time to code DR handling for the BUS controllers the results would be a less responsive controller.  In my opinion you are better off leaving them using the current plugin and leave them at Mach3.  The DR is just such a powerful tool to the programmer that using that exclusively will improve performance.

I don't say that lightly either because my hobby CNC uses an Econo 1843    But you got to do the right thing.

I will say this I have only dealt with the econo series Bus controllers, I do believe the accelera bus controllers can handle DR using the same programming techniques that ethernet controllers use.  So you might just be able to drop the econo bus and not have to do any special coding for the accelera bus controllers...  I checked and Accelera Bus does except the DR command.  Also checked and the Econo Bus controllers have to use the QR command which is not efficient and takes extra coding effort.

Matt

6

Galil / Re: Problems with losing position

« on: February 12, 2014, 03:01:51 PM »

Hi Steve (Smurph),

Tried the new plugin on a 2133, it works great, after Stop it is able to return to zero  .  Tried several times to make it loose position and could not loose position.  Plan to cut a bunch more in the next few days so will keep an eye on it.  Also I searched the log on both DMCs and only saw a DP on start up, which seems acceptable...

Note: If you did not do a DP on start up and instead use the position that is already in the Galil to update Mach's DRO it would be a bit better.  Then a user could go into and out of Mach without loosing position.  I would not classify this as a bug, more a potential enhancement.  With this change only a Ref Home would do a DP.  Again not a big deal, the way it is works (might even be best practice to force users to Home on Mach start up), just a thought.

Thank you,
Matt

7

Galil / Re: Problems with losing position

« on: February 12, 2014, 11:20:53 AM »

Steve,  I got try your new plugin on a 1843 last night and it was spot on.  Now when I press stop, then Goto Zero it is correct!    I hope try this on a 2133 soon, I will report the results.  I also note that the Stop event seems smoother now, not such an abrupt stop.  All in all a definite improvement!

Thank you for the fix and all your efforts,
Matt

8

Galil / Re: Problems with losing position

« on: February 11, 2014, 10:04:55 AM »

Wow Steve that is great!  Thank you for getting this fixed so quickly!

I will test this version thoroughly today on an 1842 and a 2133, will plan to report by Wednesday morning.

Thank you for what you and Ken do to make the world of motion control better!

Matt

9

Galil / Re: Problems with losing position

« on: January 29, 2014, 03:22:28 PM »

For further testing I tried a CNCs Mill with a DMC2132 that is normally run in production using Galil Tools. I installed Mach3 with the GT plug in, (the other tests are with a 1842 ST plugin).  I ran a small square successfully, every time I press stop I lose position slightly in the axis that was moving, just like the other CNC.  I went into the log and I see a DP sent everytime I press stop.  The way I think it needs to be is Mach3 needs to be asking the Galil,  "After that stop I just told you to do, where are you?" (TP) "Thanks I will use that to update my DRO", not the way it seems to be going of "Hey Galil stop... Here is my DRO" (DP).  I also see every time the reset is pressed a DP is sent. It is looking to me like the Plugin needs a tweak, commenting out all the DP commands should do it, other than the DP associated with the home move.

Please do not take offense to what I am saying above, I have been a Galil developer for many years, so have a fairly high experience level with Galil commands.  I am just trying to be as helpful as I can be for troubleshooting this issue.  I am really hoping  that I have a basic setting wrong and the problem is on my side, that would be awesome. 

Highest regards!

10

Galil / Re: Problems with losing position

« on: January 29, 2014, 12:50:52 PM »

Here is my Mach3 config, perhaps that will help see if a setting I have done is causing the DP.

Thank you.