Messages

71

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 31, 2008, 05:09:52 PM »

Hi, I just upgraded from Version 2.63 to the latest version and I STILL have the problem...  I just reset my Geckos to 10 u/s per Step instead of 5 and the loss of steps on My test program is nown 1/2 what it was.  Looks like it isn't the Geckos.  Hopefully, when the new Buffer IC for the breakout board shows up I'll have better luck.  I doubt the software is at fault unless there is a setting somewhere that got toggled without my knowledge ( Very unlikely).  If it was a problem with Mach, I would expect to see a lot more people reporting it.  I'm hoping it's the BOB or possibly the PC.  The pc is a PC Chips Mobo with an AMD Athlon 2500+ proccessor.  Sooner or later I'll find the problem.  Good luck to you, Don

72

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 29, 2008, 04:42:02 PM »

I dont have the other component that plugs into the Gecko mainboard, but still wonder why the computer would send out signals to the drives that are smaller by 1/2 than the resolution limit of the Mach3 Motor tuning setup?  Also the Gecko on this axis is now the one I recieved only a few weeks ago.   

73

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 29, 2008, 04:24:56 PM »

Arrgh!  Its Back!  Tried to run the repetitive program last night and at first it seemed all right. tried upping the feed from 4ipm to 20ipm but at F8.0 it lost steps again.  I tried acceleration set as low as .16667 (default from entering .01) and up to 20 but it loses the same number of steps each time...  So, I shortened up the amount of X travel to .100 to save time and adjusted the feedrate until I determined that the lost steps occur at anything over 7.5887ipm.  At 7.6ipm feedrate no steps are lost at any acceleration setting.  So, I shortened up the X-travel while leaving the acceleration at 2 and the feedrate at 2 and found I was losing steps again.  Shortened up the X to .0002" and the machine just vibrates over the .002" of lost steps.  Now the wierd part.  My machine has a max resolution of 10000 steps per inch.  I set line 6 of the program to .000005 - half the minimum travel resolution of my setup. when I ran the loop program, the machine almost smoothly moves positive .002".     Is this a software issue?  Is this a computer issue?  Is this a breakout board issue?  I was leaning toward the BOB but theoretically, the machine shouldn't move any where if the commanded movement is smaller than the resolution of the machine and its software settings, shouldn't it?  At any rate, new sn74ACT245 buffer should arrive next Monday.  I did try this program both in Constant Velocity and Exact Stop modes.  It made no difference.  When I got done running all these tests, I reset the distance to X .100 and feedrate 2 and now it was losing steps at those settings too.   Did something warm up and puke, or was I imagining things at first...  Thanks for any help you can provide, Don

74

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 28, 2008, 04:03:29 AM »

Hi, Again, Guys.  I think I've finally solved this one...  I downloaded and installed the latest version of Mach3 from the website, and Lo and Behold---  The test programs work perfectly!    I thought I was in for a defective mobo or BOB but it was just something in the software...  Repeated testing in all axes and both directions are showing perfect repeatability.  I quess there have been some major improvements in the Lockdown version of Mach3. I guess the moral to the story might be to always use the updated version of the software.  Good work,  Thanks, Don

75

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 26, 2008, 12:48:44 AM »

Hi, again.  Brain is still cogitating on this problem and I was reading thru this thread again:
Here is a similar topic.   http://www.machsupport.com/forum/index.php/topic,7364.msg47127.html#msg47127
I am wondering a couple of things...  Does anyone know what symptoms a bad Buffer IC would exhibit?  Reason for My asking is that the PMDX-120 B.O.B. has a step and direction buffer that is socket mounted in case there are any "mishaps". The buffer is a SN74ACT254.  I am wondering if replacing it might be worth a try...  Might take a while to get one, but if it is a breakout board issue, it sure would be nice to fix.  If anyone has any experience with these devices, I would appreciate it, Thanks Don

76

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 25, 2008, 11:51:35 PM »

Hi, again, and Merry Christmas to you all.  I've had a chance to play a little and checked some things with my breakout board...  The breakout board is a PMDX-120 ( www.pmdx.com) and it has a feature called Step and Direction Conditioning Modes.  Mode "0" is no conditioning. Each of the other modes regenerates or retimes the step pulses or latches the direction signal to either the rising or falling edge of the step pulse.  I found that modes 1 and 2 both doubled the error.  None of the other modes did anything different than mode "0".  Mode 1 provides step regeneration on the rising edge of the incoming step pulse, and No direction latch.  Mode 2 latches the direction signal to the rising edge of the incoming step pulse, but does nothing to the step pulses.  I am wondering if this means something???  Thanks, Don

77

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 22, 2008, 03:53:35 PM »

Hood, Naa. I just got the chance to see the postings.  I know the wiring looks a little rough, but it is actually safe and clean.  It has worked for over 2 years. 
Overloaded, I just tried raising the step pulse to 5 and had no change.  Had to exit Mach to get the number to persist, as in the other thread.  Earier version of Mach3...
Thanks, Don  P.S.  I'll be going to work soon...  I Owe, I Owe, So Off to Work I Go...

78

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 22, 2008, 03:33:00 PM »

Hi, the mystery stuff is not a cap.  The red is a collar on the grounding lug underneath the terminal block to the mounting screw for the shield on the cable.
The black tape on the end of the cable keeps the shield foil and the 4th, unused conductor held back tidy.  The current set resistors are made up of 2 resistors in series with red shrink tubing on the outer ends to prevent smoke...  Z axis has 3 resistors due to it being a different current value.  The Manual does not require additional Capacitance at the terminals like the earlier units did.  The case is wider to accomodate the built in unit.  Hope this helps dispell any Red Herrings
Thanks,Don

79

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 22, 2008, 01:08:13 AM »

Hi, again. below is a description of the tests Mariss had me try and my results.
Mariss, I just ran the tests you suggested. 1" and back and lost
about .0002" each repitition. Running the 10 reps lost .0020" and
100times lost .020" . The mark on the stepper pulley was off a
corresponding amount as well as the dial on the ballscrew end
opposite the drive. Then I set the No Auto-Standby mode and it had
no effect. What next? Thanks, Don

--- In geckodrive@yahoogroups.com, "Mariss Freimanis"
<mariss92705@...> wrote:
>
> 1) Set up a test program where you move some distance (1"?) and
back.
> Repeat it 1, 10 and 100 times. Does the error grow a repeatable
> amount; 1, 10 and 100 times bigger?
>
> 2) Take a Sharpie pen or a scribe. Mark a line from the motor
shaft to
> the motor body. Does the mark line-up after 1, 10 or 100 tries of
(1)?
> If not, is the angle error 1, 10 and a 100 times greater when you
run (1)?
>
> 3) Try setting the drive to "No Auto-Standby" on the option header.
>
> Mariss

80

General Mach Discussion / Re: My X-Axis is losing steps!

« on: December 22, 2008, 12:06:49 AM »

Hi, Rich.  Thanks for the suggestions and encouragement.  I'm also posting in the Yahoo! Gecko forum and Maris has just suggested the pointer on the motor too. he also suggests a couple of other tests for repeatability at different distances to see if it is drifting relative to the amount of travel.  I will try those steps soon and report back.  He also suggests trying "no auto standby" on the option header as another test.  Thanks, Don