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Problem executing calibration while executing calibration

Hi,
I bought the Maslow long ago , without the Z-axis motor .
I only got around finalizing my build now, and wanted to calibrate.
Screenshot%20at%202019-06-13%2016-48-58
I first tested the motors/encoder and all passed.
While calibrating a have a few bizar things and wanted to know is this normal? or what can I do to improve this?
To be clear, I execute the “Calibrate” step from the “action” menu.
After measuring the distance between the motors, using the chain withe the left , next item is Adjust Chain Lenght? Up till here , all normal.
While doing adjust chain length, the right motor works correct but the left motor started turning also counterclockwise, like the right motor ???
I started over and lay the chain like on the right motor ( This is not correct, but to continue the calibration, I skipped this error for now) . Off course it doesn’t come any near center while attaching the sled…
Then home position the Z-axis:
First of all, during the calibration steps, there is nowhere to set the travel per turn, or did I miss something? Because I don’t have an original Z-axis motor, but a similar one, I will need to be able to set this. ( If I wanted to buy a original Z-Axis Kit from Maker Made, to send it to Belgium , this would cost around 75$ for transport, on top of the 75$ for the motor. I find that a bit expensive :slight_smile: )
While wanting to adjust the z-axis inward during the calibration procedure, the right motor moved also ???
Then wanted to go outward again and it still went inward and broke the Motor holder because it was to far before I could hit stop.
Is there anything known about this weird behavior of the motors?
Many thanks in advance for possible advice

Sorry you waited more then 2 hours. I’m of not much use today, other then go thru the standard questions to provide a ground for others to help.

  • what OS are you running?
  • did you check the Wiki how-to-get-calibrated
  • both motors are turning the same direction on feeding out the chains?

Kind regards, Gero

I am running Groundcontrol on Ubuntu Mate 18.04 .
I did check the Wiki how-to-get-calibrated and all goes well up to step 10,
From step 11 it goes wrong .
in Step 11a point 3. , it says : The left sprocket will turn counter-clockwise and retract the chain to a determined length (suitable for connecting to the sled). Well, mine ran clockwise instead of counter-clockwise ???
the right sprocket ran clockwise as well, but is OK because it is supposed to :slightly_smiling_face:

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Assuming that your secure with top-feed/bottom-feed and have triple checked each number you entered in calibration, there is a slight chance that you would need to wipe the eprom and start over.
Are both motors turning the same direction feeding out the chain?

Edit: left pic top-feed, right is bottom-feed

Edit2: They turn the same direction, did you turn off the PC in between? It could be worth to close everything and also disconnect the arduino and plugging back and restarting.
Directly under /home/{your-user-name} there should be a groundcontrol.ini, in your GC folder there should be a log.txt. Can you zip and upload those 2?

The hard way to erase would be to use the ‘wipe eprom’ in GC -> actions -> advanced and delete the groundcontrol.ini and start all over.

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not really… :wink:

They are supposed to feed out opposite, the direction depending on top/bottom feed.

A picture of your setup could also give clues :boom:

if the left motor turned clockwise its because it thinks you are using “chain off bottom”. What setup are you using? The picture @gero posted shows the two types… new frame design is typically “chain off bottom”… old frame design is “chain off top”. If you are using “chain off bottom” then you should using Step 11B, not Step 11A.


hi all,

thanks for your help.
As you can see from the photo, I have chosen “chain of top”.
The part I still don’t understand ,is why both the left and right motor turn counterclockwise, and not the left clockwise and the right counterclockwise.
The other part that is a complete mystery, is why the right motor also turns when I wanted to move the router inward during the Z-axis calibration. then when I noticed that the right motor also turned and wanted to move the z-axis ( and thus the router) outward again, the z-motor turned again inward instead of outward ( i clicked the correct button, I’m, sure of that :slightly_smiling_face:)…

I will reset everything and start over again.
I decided to go with the system “Chain of bottom” so while doing the reset , I also change the way the chains go etc.
Keep you updated

With this setup, the left chain should be long from the motor distance measurement. It is not moved and will retract to the correct length. The right chain will feed out. So both counter clockwise is correct.
This will change with ‘bottom feed’. Here you need to feed them both out from the first link.

What is the pinout of your similar z-motor and encoder?

OK , that solves that mystery :slightly_smiling_face:,
I didn’t read the wiki correctly, so my mistake. I removed the left chain and did the right motor first.
Then wanted to do the left chain and the motor turned in the other direction than I imagined.
Thanks for the clarification.

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The motor and encoder are exactly the same as the original one, even the connector. Only the gearbox is different.

Why the right motor turns together with Z remains a mystery. Also why Z moves same direction on different buttons.
If you can replicate that issue, it’s worth to delete the log.txt, replicate the steps and then upload the log. This way we could check what commands are sent and what the firmware response is.
I fear that if this issue is persistent, a ‘brain-wash’ -> wipe eeprom could be a way out.

I’m on a little weekend holiday now, Monday back home.
Tuesday evening I’ll redo the whole calibration.
To be sure I start clean, should I reload the firmware in the arduino Mega or is there a better way?

Reloading the firmware is not a bad idea, but not needed i think.
A complete fresh start would be to wipe the eeprom, close GC and rename the groundcontrol.ini.
If you are up for editing a .txt file before doing a new calibration, let us know.
Entering already known numbers can speed up calibration buy skipping those parts.
Would you upload your groundcontrol.ini? I would do a quick look over it and highlight a few numbers to double-check manually. (notice that the path to the last loaded .nc file will give away the username on your device. Edit out before uploading :wink: )

groundcontrol.ini (1.4 KB) this is the old one with the partly done calibration. I hope it’s the good one. If not, I’ll check tommorow

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I remember someone else having this issue. I think it came down to the encoder not being able to parse out direction. @marcething, are you certain the encoder is the same as the stock? Or is the pinout just the same?


The output axis of gearbox is 8mm diameter and does about 60rpm.
The first photo is from the hall sensors of a second defective one.
I have no idea what the original looks like, of course, but this is my motor.

The weird part is then : Why do the motor and encoder tests pass then, also for the Z-motor???

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the maslow firmware does make assumptions about the direction that the motors
travel, I don’t remember the exact failure, but you can try switching either the
motor wires or the encoder A/B wires and see if that makes any difference.

David Lang

The pins look good