X axis runs backwards... I think

Hello

I am using Camiel's gen6 board and optos.

I am having a strange problem. My X axis seems to run backwards. I click home and it moves away from the Opto. If I move it towards the opto once the flag trips it it wont move as it thinks I am forcing it the wrong way. Both the Z and Y are working fine, and are wired the same as the X.

Has anyone else come across this?

James

There should be a setting in whatever firmware you're using to control axis direction. At least, my Tonokip firmware for RAMPS has it.

There is also the potential for confusion about which direction is positive on the Mendel and derivatives, if you're not already comfortable thinking about machine axes' relative motion. X or Y may seem backward to some, because in one case the extruder moves relative to the table, and in the other case the table moves relative to the extruder. Looking at whatever you want to be the front of the machine, the -Y end stop should be away from you, and the -X end stop should be on your left.

No problem. You can either switch the leads to the stepper motor or change your firmware code. Changing the leads is better since you'll probably be consistent with future versions of the firmware. I think you can either switch the 1st and 2nd and the 3rd and 4th with each other. Or you can switch 1 & 3 and 2 & 4. You can't break anything by switching the wires as long as you don't short them.

I just realized that you didn't say what machine you built. Is it a std Sells Mendel or Prusa Mendel? On the Sells, the Y-axis motor would be in the back and on the Prusa, I think it's in front. Also in the Sells, the X axis origin is near the Z axis motor.

Edited 1 time(s). Last edit at 03/19/2011 11:37AM by brnrd.

Thanks for the quick replys I will try changeing the leads around.

James

Swoped 1 and 3 and 2 and 4, works right now.

Thank you

Hi James,
I just bumped into the same problem as you. I took the software approach, not wanting to swap the wiring around on just one motor.

How'd you get on with the Optos? I had to make a firmware change to accommodate those also. It was a bit of a learning curve. There's a bunch to learn about changing the firmware, recompiling and re-downloading to the Gen6 electronics.

If you have the "TCST2103" Opto from Mendel, there's a firmware change for those, even if you get the 'latest' firmware from 'Mendel-Parts'.
In short X, Y and Z_ENDSTOP_INVERTING gets set to 'false' for those Optos.

On the configuration.h tab---
// New Endstops from Mendel-Parts are non-inverting (TCST2103), (so false below)
// But if you use our older endstops, those were shipped before 17Dec 2010, you need true
// This firmware version is for old type opto, so true below


#define X_ENDSTOP_INVERTING false
#define Y_ENDSTOP_INVERTING false
#define Z_ENDSTOP_INVERTING false
---

To reverst the X motor in the firmware change the #define INVERT_X_DIR to "1".

again on the configuration.h tab
---
#ifdef GRUB_PULLEYS
// define the XYZ parameters of Mendel - grub-screw pulleys

#define X_STEPS_PER_MM 40.000 // Edited 20100715 @ EJE 10.047 // Edited by CamielG @ 20101216 - 40.000
#define X_STEPS_PER_INCH (X_STEPS_PER_MM*INCHES_TO_MM) // *RO
#define INVERT_X_DIR 1
---

Regards,
No.6

---

[numbersixreprap.blogspot.com]

I had the same issue. Being a manufacturing/mechanical engineer I took the hardware approach and swapped the wires.

I had the same problem with the steppers and optos, so I swapped wires etc. then download the very latest firmware off mendel-parts.com and found that they were fixed in software already, so I swapped them back again.

Cheers
Geoff