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Self Changing Velocity
« on: April 24, 2017, 02:35:44 PM »
I was having a problem with three minitech machines loosing their Z height in the middle of running jobs, resulting in inappropriate depths machined into the items I'm running, as well as a Z axis plunge. The change in the Z height was random, there wereno set depth changes. I believe the issue was that the velocity on the machines were set way to high, which brings me to my actual question/problem. I have not changed the velocity myself.

We have five machines, three of which were serviced. The ones serviced all had a change in their velocities. The machines not serviced are fine. No one has access to the machines other than three operators, myself included, and the person who serviced the machines. I tried contacting the company that serviced the machines but they believe we changed the velocities on our own, they didn't seem to believe me when I said we had not adjusted anything. They also believe the issue is resolved as we changed the velocities back to their original setting per their instructions.

While our machines were being serviced the person said they did find a velocity that was too high on one of the machines and changed it back to normal. With that said, I don't know what to do. The velocity on one machine was found raised too high, adjusted, and then was raised again. Non of which we did. I cannot think of what might be changing the velocity. I asked the company if it was possible that something was triggered or there was a chain reaction of sorts to change the velocity during the servicing. I was told to not adjust the velocity as a response. Our machines cannot be run overnight (which is their intended use) if we cannot trust that the issue won't occur again.

Any thoughts, opinions, insights, etc. would be greatly appreciated.

Offline RICH

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Re: Self Changing Velocity
« Reply #1 on: April 24, 2017, 03:19:05 PM »
What version of Mach are you using?
Are you using the generic Mach screen?
Are the machines steppers or servo's?
What drives are you using?

If they worked fine before, then if they are using the same velocity , acceleration, etc settings they should be working fine after
being serviced. So why not just change the serviced ones to the settings of the machines that are repeatable and working fine.

You tune a stepper by trial and error and set the accel and velocity for reliable operation for what you are doing.
The only thing that will change the velocity setting is the gcode instructions or use of the override, but even that is restricted to the max setting.

FWIW,

RICH
Re: Self Changing Velocity
« Reply #2 on: April 27, 2017, 08:20:32 AM »
The main issue we are having is two of our machines were set 100% correctly, then one changed its velocity of its own accord. The velocity on that one machine was corrected while being serviced. Now all three of the machines have an inaccurate velocity, again. We are not making the adjustments. The machines are changing on their own and the issue is we don't know why it is happening or how to prevent it from happening. We do have settings that we like and that are accurate, they just don't seem to stay consistent. The three machines that were serviced are the only three that are running with problems.

The machines without issues are both Mach 2s
Two of the three with issues are both Mach 3s
One of the three with issues is a Mach GX

The GX had the problems before the machines were serviced and the other two only after the machines were serviced.

We are not using the generic screen.

Our machines have stepper motors.

I might need more clarifications on what you mean by drives.

Thanks

Offline Tweakie.CNC

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Re: Self Changing Velocity
« Reply #3 on: April 27, 2017, 08:48:25 AM »
I know it's of no help to you but I have been using Mach2 / 3 for over 10 years now and my Velocity settings have never once changed on their own.

I would suspect human intervention and suggest that you talk with whoever serviced your machines to determine exactly what was done. Having said that, if you copy the Motor settings from the working machines to the non-working machines that should put everything back to as it was.

If, for some reason that does not work then if you post the <your profile> .xml file from the Mach3 folder of a working machine and the <your profile> .xml from the Mach3 folder of a non-working machine (they need to be renamed something like working.xml / nonworking.xml before posting) then we can check your settings and see if the problem can be identified.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Self Changing Velocity
« Reply #4 on: April 27, 2017, 09:11:47 AM »
Human intervention was my first thought too. It makes sense to me as two of three machines were fine prior to servicing and now after servicing all three are malfunctioning. Especially as our only two working machines were not serviced. However the person who serviced the machines said they only changed the one setting back to where it should be.

I am uncertain if the company just doesn't want to admit they made adjustments or they could have made a mistake or what but they are the only option for a manual change. That is why we are at a loss as to what to do/ what happened. We cannot trust these machines to run on their own with the damage the velocity change inflicts if we cannot figure out how the change occurred.

As far as the Mach 3 file goes, we don't have a working machine. We have only two Mach 3s and neither one works.

Offline Tweakie.CNC

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Re: Self Changing Velocity
« Reply #5 on: April 28, 2017, 01:23:25 AM »
My apologies, I misunderstood.

An alternative approach…

Mach3 saves all changes to it’s settings in the <your profile> .xml file when it shuts down. These changes are also saved in the xmlbackups folder. Choose a backup (from a date before your machine was serviced) copy this file, change the file extension to .xml and copy it into the Mach3 folder (replacing the existing file).
This should then restore all your original settings and make your machine behave exactly as it did before the service.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline RICH

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Re: Self Changing Velocity
« Reply #6 on: April 28, 2017, 08:49:03 AM »
Do as Tweakie said per reply #5 and that should fix the problem.

When you say velocity I am assuming that you are talking about the velocity setting in motor tuning. Correct?


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They also believe the issue is resolved as we changed the velocities back to their original setting per their instructions.

What instructions did they give you?

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We are not using the generic screen.

Don't recall any threads on the motor settings changing randomly and never experienced it myself. Not aware of any scripting that would do it. I can't help you with a custom screen set since who knows what is in the screen set.SO hopefully changing back to an earlier xml will solve the problem.

RICH

Offline rcaffin

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Re: Self Changing Velocity
« Reply #7 on: April 29, 2017, 03:46:40 AM »
You might profitably consider changing the servicing company as well.

Cheers
Roger