Scaling issue on Y axis for tool rack

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axeman
Posts: 15
Joined: Thu Jan 25, 2018 2:40 am

Scaling issue on Y axis for tool rack

Post by axeman » Mon Dec 13, 2021 5:09 am

Greetings,
I have been setting up a tool rack for ATC upgrade. Tools are spaced along y-axis with the distance from T1 to T12 about 900mm.
When moving to the absolute Y positions for tool holders there seems to be a scaling error. The actual position gets increasingly out until the final tool position is out by about 1.8mm. So starting from safe position Y902.55 and going to T12 (Y29.0mm) the spindle actually lines up at Y27.2
I have checked the cnts/mm and that is correct for the machine.
But I did play around with the cnts/mm and found that I could get it to line up at T12 only to discover the return to safe position after loading tool was now out.

I also tried changing the absolute y position values, then downloading and running again, but oddly I am getting the same result as if I had not changed them. Even after changing values T12 still goes to Y27.2mm.

I have used the sample program included with software (ver435f) and modified it for the Y axis. See attachment.

Any help solving this issue would be much appreciated.

Laurence
Attachments
Linear12ToolHoldersGeorge_Y-Axis.c
(12.18 KiB) Downloaded 54 times

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TomKerekes
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Re: Scaling issue on Y axis for tool rack

Post by TomKerekes » Mon Dec 13, 2021 4:54 pm

Hi Lawrence,

I'm not sure I follow all of that.

You might first check if the system is loosing counts. If you start at one commanded Destination and at some physical position, then make many large moves and then back to the same commanded Destination, is it at the same physical position as before?

How do you know and check the cnts/mm is correct for the machine?

If you change the cnts/mm then the SAFE position would shift. Why not then correct it?
Regards,

Tom Kerekes
Dynomotion, Inc.

axeman
Posts: 15
Joined: Thu Jan 25, 2018 2:40 am

Re: Scaling issue on Y axis for tool rack

Post by axeman » Tue Dec 14, 2021 1:20 am

Hello Tom,
Thank you for your response.

I have checked by moving over 10 large moves and then coming back to the initial position and that is still at the correct original physical position.

I have checked the cnts/in (The units are in inches in the machine setup screen) for the machine by marking an initial physical position at X0Y0 and moving 900mm to X0Y900 and physically marking this position also. I then measure the distance with a steel rule. I can thus confirm the cnts/in are accurate for my machine, in the machine Trajectory Planner screen.

To your third suggestion: Changing the cnts/mm to something other than what the machine is correctly setup to seems suspect to me. But I will leave that aside for now. Except to say I have double checked my unit conversions and they are also correct. Anyway, it is only the Y-axis tool holder positions that are the problem.

However, after further investigation, I may be getting closer to the issue.
I can change values for positions for variables like HOLDER_X and HOLDER_Z, and pretty much anything else and save, download, and run the edited program and the machine moves physically to the updated positions accurately and as expected.

However, I have discovered that if I change the values for the HOLDER_Y variables, then after save, download, and run, the spindle still travels to the previous position values and not the new positions. So there doesn't appear to be any scaling issue. It appears to be a problem with updating the new edits to the program. This suggests to me the old values are stored somewhere and are still being accessed even though the program itself has been changed and shows the new values.
I have tried shutting everything down and restarting, initializing again but it seems I can't refresh to the updated HOLDER_Y values.

To be clear, this only seems to happen with the HOLDER_Y values, all other changes update as expected.

Any ideas?

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TomKerekes
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Re: Scaling issue on Y axis for tool rack

Post by TomKerekes » Tue Dec 14, 2021 4:12 pm

Hi Lawrence,

Do you realize the program only uses HOLDER_Y_1 and HOLDER_Y_2 ? And the other 10 are not?
Regards,

Tom Kerekes
Dynomotion, Inc.

axeman
Posts: 15
Joined: Thu Jan 25, 2018 2:40 am

Re: Scaling issue on Y axis for tool rack

Post by axeman » Tue Dec 14, 2021 9:49 pm

Tom,
No, I did not realize this. Now that I do, everything makes sense again and I have sorted out the problem I was having.
I apologize for being dumb and taking up your valuable time, but thanks all the same. Your support is second to none!

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TomKerekes
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Re: Scaling issue on Y axis for tool rack

Post by TomKerekes » Tue Dec 14, 2021 9:54 pm

Hi Lawrence,

Thanks and thanks for taking the time to post back.

Good luck.
Regards,

Tom Kerekes
Dynomotion, Inc.

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