RAMPS 1.4 won't drive (2) Z steppers, does either (1) fine

Hello!
I have finally found the time and motivation to build a prusa i3 based printer. I have everything together and it's all wired up, and ALMOST everything is working as expected. The only problem I have is my Z axis. When I try to move my Z axis both steppers make some loud noises but don't go anywhere. I have tried the following:

Removed lead screws so steppers have no resistance and tried again (steppers still didn't move)
Unplugged 1 stepper, the one still plugged in moved perfect after this. (and vice versa when I switched them)
I tried turning the POT on the driver up to provide more current. This changed the tone of the loud noise the steppers were making, but nothing else

What's really strange about this is, before flashing the latest Marlin to my Arduino board, I had an older, modified Marlin I was using to control my Printrbot Simple Metal. Before I reflashed it, I had it all hooked up and decided to try moving the motors to make sure things were hooked up right. I was able to move X, Y, AND Z without issue. So I'm confident this is a firmware problem. Some setting I missed somewhere, but I can't figure out where.

I started with a fresh git checkout of the latest Marlin firmware and made the following changes:

--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
- #define MOTHERBOARD BOARD_RAMPS_14_EFB
+ #define MOTHERBOARD BOARD_RAMPS_14_EEB

- #define TEMP_SENSOR_BED 0
+ #define TEMP_SENSOR_BED 1

- #define X_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
- #define Y_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
- #define Z_MIN_ENDSTOP_INVERTING false // set to true to invert the logic of the endstop.
+ #define X_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.
+ #define Y_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.
+ #define Z_MIN_ENDSTOP_INVERTING true // set to true to invert the logic of the endstop.

- #define INVERT_Z_DIR false
+ #define INVERT_Z_DIR true

- #define INVERT_E0_DIR false
+ #define INVERT_E0_DIR true

- //#define LCD_FEEDBACK_FREQUENCY_DURATION_MS 100
- //#define LCD_FEEDBACK_FREQUENCY_HZ 1000
+ #define LCD_FEEDBACK_FREQUENCY_DURATION_MS 100
+ #define LCD_FEEDBACK_FREQUENCY_HZ 1000

- //#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
+ #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER


--- a/Marlin/pins_RAMPS.h
+++ b/Marlin/pins_RAMPS.h
- #define BEEPER_PIN 37
+ #define BEEPER_PIN -1


Any help is appreciated.

Adjust the z setting in these lines, by lowering them:

#define HOMING_FEEDRATE {50*60, 50*60, 2*60, 0} // set the homing speeds (mm/min)

#define DEFAULT_MAX_FEEDRATE {300, 300, 3, 25} // (mm/sec)

The above are what I'm using for TR8-8 screws.

Quote
stephenrc
Adjust the z setting in these lines, by lowering them:

#define HOMING_FEEDRATE {50*60, 50*60, 2*60, 0} // set the homing speeds (mm/min)

#define DEFAULT_MAX_FEEDRATE {300, 300, 3, 25} // (mm/sec)

The above are what I'm using for TR8-8 screws.

Thanks! I'll try this when I get home. I don't seem to have HOMING_FEEDRATE, but I do have HOMING_FEEDRATE_XY and HOMING_FEEDRATE_Z. I guess this goy split into 2 settings somewhere along the way. I'll apply your settings to HOMING_FEEDRATE_Z and see what happens.

EDIT: Actually, just realized since it's split out, I should change

#define HOMING_FEEDRATE_Z (4*60)
to
#define HOMING_FEEDRATE_Z (2*60)

and use your DEFAULT_MAX_FEEDRATE as-is. That sound correct?

Edited 1 time(s). Last edit at 08/15/2016 11:56AM by timekiller.

Looks like they changed things again...

Yes. The first one basically cuts the z homing speed in half and the other reduces the max feedrate for the z-axis.

RAMPS provides two parallel connected Z stepper outputs. Like some other RAMPS features, this is a bad design decision, given the types of stepper motors generally used with RepRaps. If reducing the maximum Z feed rate and acceleration don't get it working, then try connecting your Z stepper motors in series instead of in parallel. Google "wire stepper motors in series" for how.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

OK! I was able to test stephenrc's suggestion and...it worked! (sort of)...

Now when I home Z it moves smooth as butter. But if I try to move Z manually, 1 or 10 mm I get that same annoying noise and no movement. Looking through the config now for another Z movement section, but I'll take a hint if it's offered

EDIT: This worked:

#define DEFAULT_MAX_FEEDRATE {300, 300, 2, 25}

Edited 1 time(s). Last edit at 08/15/2016 07:22PM by timekiller.