Lots of issues calibrating

Hi everyone,
I’m now, just got my Maslow a week or so ago & started building the Temp frame over the weekend.
First, let me thank you for this great tool, kit, software, etc… It’s really impressive how much work you’ve put into it.
However, I had a lot of issues with the calibration process.
I had to re-run it at least 5-6 times before I could get it right & I had to skip some steps to even get there…
I’m on version 0.98 of the firmware & GC.
I’ll try to explain all of the issues here if I can remember them all.
Issue 1. At step 6, I got these measurements:
Motor Spacing: 2975mm
Sled Mount Spacing: 222mm
Vertical Offset: 367mm

I verified these measurements with my tape measure & they looked pretty accurate.
Then at step 7, I got this message (maybe it was after the chains measured out)

Issue 2. Also at step 7, the left & right chains measured out, then it says to re-attached the sled & hit next & it will re-center the sled. I attached the sled (it already looked pretty centered to me), then hit next & it spun out the chains all the way & dropped the sled on the ground. I had to re-attach the sled, assuming it was centered & hit the skip button, instead of the Next button to get past this step.

Issue 3. Also at step 7, it first spins out the left chain & then the right. There needs to be a pause or delay after it’s done with the left motor & before it starts the right motor. Because there’s not enough time for me to get from the left side to the right side before the chain starts to wrap its self up on the sprocket.

Issue 4. Also at step 7, I can’t remember if there’s a “Stop Motors” button or not at that step. It a panic I had a hard time finding it & sometimes they’re inconsistent. Some of them say “Stop” and some say “Stop Motors”. Since you’re working on colors, they should be big red bold & consistent.

Issue 5, can you speed up the motors for the calibration process? When you have to do it 5-6 times it takes hours.

I’m sure I had other issues, but can’t think of them now. I’ll let you know when I re-calibrate with my final frame.

Thanks for the help,


I’m sorry to hear that. I would really like to figure out what went wrong to make the process take six tries.

Those measurements look good, and the unable to find valid machine position error usually happens when the measurements don’t make sense so I’m not sure why that was happening. Let me think on it and see if I can find a reason that would happen. Maybe the settings weren’t being sent to the machine correctly? Have you had any connection issues?

Having the wrong dimensions sent to the machine would cause the behavior you saw where the sled went off the bottom. Basically if the machine thinks the motors are a fifteen feet apart it will just try to feed out chain until the sled goes off the bottom in an attempt to find the bottom.

If you keep seeing the issue would you be willing to send me the “log” file that is saved by Ground Control? It’s overwritten every time Ground Control launches so you’ve got to copy it before launching Ground Control again. It should be in the Ground Control folder next to where you launch the program. That would let me take a look at every command sent back and forth to and from the machine.

Adding two buttons one for each side is something we’ve talked about before and I’ll do that right now. I wish I could make them go faster, but the chain tries to wrap itself around the sprocket a lot more when they turn faster.

Let me know how your next calibration process goes and if it’s smoother. If you run into any trouble, make a copy of that log file for me and I’ll be able to give you much better insight into what is going on. Finding a simple calibration process is something we’ve been working on for a long time, and there’s still a lot of room to simplify and improve it. Thanks for the feedback.

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Thanks for the reply Bar. Are the measurement settings save somewhere locally on the computer somewhere?
I’m thinking I may have re-started the calibration process, by using the “Go Back” buttons, but not restarted from the action menu or restating GC. Maybe some old bad settings are confusing things… Anyway to start with a clean slate?


Can you give me the exact steps you took to start the calibration? I know that sounds stupid but I think I did it differently than everyone else.

Can you also tell me the type of hardware and os you are using for running GC.

IE . - I’m on a Imac with OSX 10.10 or My Windows 10 dell laptop?

I’m trying to keep track of problems that become common and their solutions.

Thank you

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The first time I started the calibration process was from Actions -> Calibrate Machine Dimensions.
After that, I’m not sure. I may have gone back 1 or 2 steps & tried again. At one point I did shut down the computer (it was getting late) & re-stated the next morning. So I re-open GC & went back to Actions -> Calibrate Machine Dimensions. I’m on a Microsoft Surface Windows 10.

Oh and @bar no I haven’t had any connection issues.

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Good question about where the settings are stored!

You can edit them manually by clicking on the Settings button at the top of the window, or if you really want a clean slate you can delete the GroundControl.ini file in your home directory (usually C:/Users/YourName). The file might be “hidden” depending on the computer settings.

I’m working on adding two buttons for extending the chains right now :slight_smile:

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I feel your pain and second the idea about adding a time delay between the left and right chain feeds… I end up letting the left chain spool down as I stand next to the right chain with my hand just an inch away from the sprocket to make sure it doesn’t wrap… and even then I get nervous.

Maybe a silly question, but are you using the temp sled with the stock L brackets or are you using a linkage kit?

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Hi @bar thanks, for adding the second button for the right motor.
I still think a delay would be helpful, as you have to hit the button & then run to the motor to keep it from getting jammed.

Oh at that reminds me. On one screen it asks you if you’re using the standard triangle mount or the linkage system. Sorry, I don’t remember the exact wording. It has 2 buttons if you hit the top button, I think for triangle option it then shows you a drop down with the same 2 options, so you have to pick triangle again.

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It should be asking for Quadrilateral (stock mounting) or Triangular (linkage kit). Which type of connection are you using and which are you picking? If you are using the stock mounting and picking triangular, that might explain your issue.

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Thanks for the reminder. I will be sure to add a delay to give time to get to the machine. Maybe five seconds?

I didn’t understand about the drop down at first, but I think I get it. It is confusing. What about two buttons, one for each option. Clicking either one will take you to the next screen, but you can always go back with the back button if you make a mistake

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Ya sorry, I couldn’t remember the correct wording.
I’m using Quadrilateral (stock mounting).
It has 2 buttons:

I think if you pick Quadrilateral, then it shows a drop down with 2 more buttons for Quadrilateral & Triangular, so you have to pick Quadrilateral twice…


Q - are you working on Windows, OS X or Linux? What’s your daily driver?

This might be covered somewhere else - What is the difference between Calibrate Machine Dimensions & Calibrate Chain Length - Automatic. I’ve read people referring to Automatic Calibration so I was / am confused.

Thank you

Sorry, I just looked at the screen again.
I now see there is a drop-down & a next button.
I guess I was getting confused expecting to see 2 buttons.
I think yes, 2 buttons would be a good option & it would go to the next screen after you picked one.
Sorry for the confusion.

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That’s a perfect example of one of those things that once you’ve looked at it a couple times it makes sense, but it’s confusing at first. Those things are SOOOO hard to track down without a fresh set of eyes. Thanks for pointing it out, two buttons it will be!

@Bee I work on an old Asus EEBOOK running Windows 10. I like it because developing on slow hardware makes it so Ground Control runs quick :grinning:


I’ve filed an issue for creating two buttons during that step in the calibration process here:

I’ve also started working on adding two buttons one for extending each chain with a delay. The reason I’ve been putting off doing that is that there is quite a bit of general clean up that has to take place before I can really do that. I’ve started the process for that here:

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I have an IBM XT under a pile of “Shtuff” here if you want to go stone ages but I think we would have to use some form of linux. lol

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Linux requires a 32 bit processor, so the XT won’t work :slight_smile:

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That is true I always forget 1993ish correct? No cross compelling to CPM.

Thank you

I may still have an ISA bus 68K coprocessor card with Microport Unix (SysV port) in the attic, plus a dual floppy 8088 system, c1983, if you really want to try old school

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