Mirrored axis

Mostly Printed CNC - MPCNC Troubleshooting
1

Hey all, just debugging my MPCNC build.

My test job is printing on what I believe to be a mirrored Y axis. I followed the advice in this post about flipping the stepper plugs and and changing #define Y_HOME_DIR -1 to #define Y_HOME_DIR 1. This setup causes some of my endstop pins to get redefined.
While normally M119 reports
x_min
x2_min
y_min
y2_min
z_min

Under the modified build M119 reports
x_min
x2_min
y2_max
z_min

I’d appreciate any advice. I think this may be the last bug I need to iron out.
Cheers

2

Change the firmware back.

Unplug the Y motor cables, flip them 180°, and plug them back in that way.

If for some reason you can’t just flip the Y motor connectors (Say, for example you used JST XH connectors) then change the firmware, in configuration.h change the line:

#define INVERT_Y_DIR true

(If it’s false, change it to true. If it’s true, change it to false.)

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3

Appreciate the reply Dan, I just need a little clarification.

Are you asking me to return evrything to the stock set up?

4

Yes. There should be no reason the stock firmware won’t work. Reversing a direction will cause mirror image final results.

Change the mechanical properties of the machine to move as the firmware expects it to.

5

Oof, I see now.

I installed my entire y carriage backwards :roll_eyes:.
Thanks

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6

Just to add a little more info.

You can and should flip the stepper cables if something isn’t going the correct way.

But don’t reverse the endstop direction in the firmware unless you want to learn a lot about the firmware.

You should be able to stand in one spot and the positive Y goes away from you, positive X goes to the right and positive Z goes up. The endstops should be in the close and left sides. You can rotate the whole table after that (or just use your imagination).

2 Likes
7

Hey Jeff,

Thanks for the reply.

Yeah, I’m realizing that I installed my Y axis reversed. My origin is at the rear left of the machine. I just assumed I could make the appropriate changes in the firmware…obviously not. It’s like you said, reversing the endstop direction wreaked havoc. I slept on it and I’m pretty sure I can flip the motors around with a minimum of disassembly.

Though everything was backwards, I’m really impressed with the machine. Looking forward to diving in.
Cheers

1 Like