I can't get X and Y to move the same! Help with settings please

Petter · January 7, 2023, 10:23am

Hey! New question!
I got help that my wires were wrongly connected, but now that I have connected 3 stepper motors, they have different speeds and move different distances.

I’ve tried searching the forum about this but can’t find anything clear that helps me.

I post my “console numbers” and “machine settings” because I think that’s where you should change things.
right now the X at toggle one click goes about 1/5 of a turn.
Y rotates 5 turns on toggle one click.
Z at toggle one click about 1/5 of a turn.

Can you understand where I have the wrong code!?

And can someone explain where I should change and why, that is, so I can understand why I change right there
I want to learn!

Petter · January 7, 2023, 10:33am

It is Arduino + CNC shield

berainlb · January 7, 2023, 10:50am

If you want to simply correct the calibration then you can modify these values:

$100, $101 and $102 – [X,Y,Z] steps/mm

More information here:

github.com

gnea/grbl/blob/master/doc/markdown/settings.md#100-101-and-102--xyz-stepsmm

## Getting Started

First, connect to Grbl using the serial terminal of your choice.

Set the baud rate  to **115200** as 8-N-1 (8-bits, no parity, and 1-stop bit.)

Once connected
 you should get the Grbl-prompt, which looks like this:

```
Grbl 1.1d ['$' for help]
```

Type $ and press enter to have Grbl print a help message. You should not see any local echo of the $ and enter. Grbl should respond with:

```
[HLP:$$ $# $G $I $N $x=val $Nx=line $J=line $SLP $C $X $H ~ ! ? ctrl-x]
```

The ‘$’-commands are Grbl system commands used to tweak the settings, view or change Grbl's states and running modes, and start a homing cycle. The last four **non**-'$' commands are realtime control commands that can be sent at anytime, no matter what Grbl is doing. These either immediately change Grbl's running behavior or immediately print a report of the important realtime data like current position (aka DRO).

This file has been truncated. show original

If you’d like to understand why and how this works I’d suggest you review LightBurn documentation on the subject:
Steps / mm - LightBurn Software Documentation

Petter · January 7, 2023, 11:32am

I don’t know, but no matter what I change in the settings in the console, I can’t get the motors to spin the same, is there any other place to change settings??

berainlb · January 7, 2023, 12:07pm

Try this as it might be easier.

Design a square in LightBurn. The bigger the better. Make note of the size.
Burn the square
Measure the square
Use Edit->Machine Settings->Calibrate Axis to tune the axes. You will need to provide the requested distance compared to the measured distance.
Repeat this for each axis.

Petter · January 7, 2023, 2:31pm

1: I have no setup with axes yet, just loose X,Y,Z motor loose on the table.
2: is it that grbl doesn’t have the same code for X,Y,Z by default??
3: does it have to do with the size of the print bed’s settings? so if I have 300x 800 when I install the card it takes X,Y,Z into account and tries to correct the speed to that??

yes, as you understand, I’m a beginner

berainlb · January 7, 2023, 5:23pm

Okay. Then you’ll need to decide what you want to accomplish. It sounds like you don’t have a particular vision for # of steps per mm that you’re targeting. In that, you’ll need to just get the appropriate belts and gears for your laser, then you can calculate the required steps based on that.

Based on your config, it shows 100 steps/mm for all 3 axes. However, because you apparently don’t have identical stepper or stepper drivers, you’re not seeing the same motion in the steppers. The GRBL values are not a standalone means of getting you consistent motion. It needs to be calculated in combination with the other aspects that affect movement that’s included in the documentation link I listed earlier.

No. Steps/mm is irrespective of overall laser size. You could have the same steps/mm for a tiny area or a giant area.

Petter · January 7, 2023, 6:30pm

ok, so if i understand you correctly, everything is in order. Until I have a frame with belts and pulleys I can’t get my motors to turn the same!?

I have the same nema 17 motors and the same stepper drivers, set to the same 0.85 v which is the correct voltage as I understand it

I haven’t built my laser machine yet but naturally know how it will look and work, just thought I’d get the electronics working first this is my first completely DIY machine, both construction-wise and with its own driver board.

I just thought I did something wrong because the motors didn’t do the same thing after installation.

Regards Petter

berainlb · January 7, 2023, 7:26pm

You could but there’s little point in doing so.

In that case it would be strange if these weren’t moving the same. How are you advancing the motion for your test?

What is the ratio of distance travelled for each motor when testing?

Petter · January 7, 2023, 7:41pm

ok, to answer your second question: i just put the motors on the table with a tape on the shoulder to see how they move.
It seems that X moves constantly if I change “Speed” in the “move” console, the same distance as before 1/5, so 5 movements to make one turn, but different speeds. Same for Z.
Y, it spins 5 turns.

berainlb · January 7, 2023, 8:06pm

Speed is not a concern as that’s runtime configured. So sounds like they’re all behaving the same with respect to distance travelled.

Sounds like you’re good to go to proceed in that case.

Petter · January 7, 2023, 8:14pm

Thank you very much for your help and I will come back later but new questions and problems! Regards, Petter

system · February 6, 2023, 8:14pm

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