Hello Guest it is August 18, 2019, 01:35:03 AM

Author Topic: Motor stalling issue. (best I can describe)  (Read 5427 times)

0 Members and 1 Guest are viewing this topic.

Motor stalling issue. (best I can describe)
« on: December 20, 2013, 09:48:27 AM »
All,
I have a new setup. (I have previous machines that work under Mach). This is a router table with 2 drives driving the X axis.(the A one is slaved)
Controller is a PDMX122, Geko 203V and Vexta Geared Motors.(PK296 series)
The PC is a Pentium 3Ghz stripped down to bare bones configuration.
and I am  registered Mach3 user too :)

All is functional. and typically the machine behaves properly.

Sometimes (pretty frequently) the motors could be any of the axis. X Y or Z (X has a slave axis)
the motors stall. The best way I can describe it is . ITs as if the velocity is set to high. (but its not)
I can tune the motors to say 300ipm range and they operate smoothly.

The problem seems to only occur on first start of any direction on any axis.  One their running I can stop and start. many times their after.
Another way of getting them to stall reliably. is to perform an "Axis Calibration" this will almost always cause the motors to stall.
Example.
Run first test... Motors stall for about a second then proceed as normal.
Run second test. Same results.
Run same test but jog motors any direction. just before hand... no stalling.
 Using the above example. I have even adjusted the motor tuning down from say 250 to as low as 20. all with the same results.

My apologies If I have not explained my symptoms correctly.

One last injection. I have ran a sample g code file with as much as 12K lines of code. and ran with out a hiccup.
BUT... the actual first movement stalled. my solution. re home. Re jog... then re run the g code file.

-S












« Last Edit: December 20, 2013, 09:50:27 AM by TheSniper »

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Motor stalling issue. (best I can describe)
« Reply #1 on: December 20, 2013, 06:52:34 PM »
Have you tried reducing the acceleration a bit, sounds like your tuning is just on the edge and that can be acceleration as well as velocity.

Hood
Re: Motor stalling issue. (best I can describe)
« Reply #2 on: December 20, 2013, 07:33:22 PM »
As already mentioed. I have reduced both velocity and acceleration to turtle speed. And the results are precisly the same. Funny thing when i reduce both of them to say 5 each ( crazy slow) same stall but only at startup snd only once per go.

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Motor stalling issue. (best I can describe)
« Reply #3 on: December 20, 2013, 08:19:11 PM »
Dont think you mentioned Velocity ;)

Try increasing the pulse width and Dir as well, probably wont help but ... well give it a go.

If you attach your xml I will see if I can find an issue with it.
Hood
Re: Motor stalling issue. (best I can describe)
« Reply #4 on: December 20, 2013, 11:28:13 PM »
I have minimized the Acceleration and velocity to what I believe too slow to even test with. But here is my current XLM for the Machine.

Things to remember. I have cut a file with +/- 11,685 Lines of code (to be exact :) )... running at about 200ipm with no missed steps.
But did on the first launch.. So I re homed& zeroed and then re ran the file. worked flawlessly the second go around.

So put another way. seems the first attempt (very first) is when the problem shows it self.

According to what I have read the steppers should be Step Pulse set @ 2 and Dir pulse left @ 0

here is the XML http://www.trickinteriors.com/MechMate-Mach3/MechMate.xml file.
(This is a new machine I have ran it for about 2 hours +/-)

Just to be sure I was clear. The so called stall's only happen at the "First movement" if its going to stall at all. In the case its going to... the first thing you hear is the stall... for about a second once recovered... it does not miss a beat. The only other scenario. Is it does not stall at first movement. and again does not miss a beat.

One thing I don't quite  understand.... Say It reliably stall's when set @ 200ipm. and I do an axis calibration.... Upon first movement. I get the stall and then the calibration goes to completion with out a hiccup their after... So I set the Speed and  Accel to 20 and 5.... I re run the Axis Calibration... Same stall same results.

I know Im prob talking out of my ars... but seems to me the motor is trying to start up if full speed mode. Like you mentioned earlier. But if this was the case.
then why does it almost reliably stall under an axis test when the setting are real low.  Also under other conditions. Only at the first move... but then never their after?

Thanks In Advance!
S-
 


« Last Edit: December 20, 2013, 11:39:30 PM by TheSniper »

Offline Hood

*
  •  25,849 25,849
  • Carnoustie, Scotland
    • View Profile
Re: Motor stalling issue. (best I can describe)
« Reply #5 on: December 21, 2013, 04:54:15 AM »
Not sure where you read that regards the Pulse widths but whatever :)
Try reducing your kernel to 25KHz, you have it at 60KHz and your motor tuning only requires 19KHz.

I would also uncheck A as angular on General config page, it shouldnt matter really as it is slaved but maybe there is something there, especially as you say it is just the first move.
Hood
Re: Motor stalling issue. (best I can describe)
« Reply #6 on: December 21, 2013, 07:04:47 AM »
Sam,
The Gecko G203Vs have an axis auto current reduction feature.  It activates after about 1 second of axis inactivity, if I read the manual correctly.  It is supposed to reduce current on standby to 70%, but some versions reduce current to 0%.   

Could your problem be related to this feature?  From your description, it sounds suspicious to me, especially since you say it happens with any axis.

John Champlain
Re: Motor stalling issue. (best I can describe)
« Reply #7 on: December 21, 2013, 07:49:43 AM »
I'll give all these changes a shot this afternoon I have to goto wk this morning. but only for half a day! :)

@Hood: In the Gecko Manual under troubleshooting is where I found the pulse widths info apparently the 203V are different from most of the other drives?.  I have tried lowering the kernel speed to 25KHz as well as many other speeds. But Im glad to try again :).

@Picengraver: Sounds like a possibility. Ill have to look into that.

 
Re: Motor stalling issue. (best I can describe)
« Reply #8 on: December 27, 2013, 06:38:45 PM »
All,
After trying many changes
1:Kernel speed I tried 25000KHz, and a few others all with exactely the same results (currently @ 25000KHz though)
2: Tried lowering the motor Velocity & Acceleration to say 10 and 10, Same results. But I can Jog all day at 250/20 with not one missed beat.
3: Played around with different Step Pulse and Dir pulse. Current setting @ 2us and 0 respectivly.
4: Tried a fresh install of Mach.
5: Switched my Parallel port from EPP to ECP
6: Set the Process "Mach" to realtime in the process manager
All with not any noticeable change in my hunt for the problem.

I cannot seem to wrap my head around the problem. Like I said in an earlier post. I ran a test file with around 10K lines of code. all with no missed beats/steps.  But had their been one it would have been upon first move.

If I had to make a claim. in regards to "can you reliably reproduce the problem?
I would have to answer "No" But I can get close.
1: When it occurs its always when the software is in control. NEVER under a MANUAL jog  does it fail.
2: typically the absolute first movement is when it will rear its ugly head
ie if the routine has 1 or 5000 lines of code it will be the first line that has movement. never afterwards.
3: I prefer to use one of the Mach blue or Hoss etc screen sets. when I do a auto Zero touch off.
it will crash during the line under the Z- button Script
"Code "G1 Z1.0 F2" 'put the Z retract height you want here"
interesting enough it also fails to retract the desired 1" but goes to about 1.5 or 2" but never 1"

Perhaps I can take a few videos and upload so the problem can be seen and heard. at the same time.

In regards to Johns suggestion I was unable to prove/disprove the motors sleeping. As Gecko is closed for the holiday and I was un able to find any iNet related issues.

-Still mystified...











 



Offline RICH

*
  • *
  •  7,351 7,351
    • View Profile
Re: Motor stalling issue. (best I can describe)
« Reply #9 on: December 28, 2013, 06:52:44 AM »
Does the skipping happen if only a single axis is used and connected?
                     "               when starting from any spot along the axis?

To find the culprit i would keep things as simple as possible as that eliminates causes.
Since it's rather repeatable as only the first move, see if one axis skips  when the motor is not driving ( ie; remove the motor coupling)
an axis.  Then do checkout in a logical way.

RICH