Hi everyone,
I am working on a project using an Arduino Mega 2560 paired with a RAMPS 1.5 board and A4988 drivers. I am trying to run Nema 17 motors (Model: 1.5A). All components are brand new 1:1. Power source: 12V 10A.
Issue:
No matter which slot I use (X, Y, Z, E0, or E1), the motor does not rotate smoothly. Instead, it stutters, jitters, and vibrates back and forth (clockwise and counter-clockwise) while trying to complete the commanded steps. It looks like it is fighting itself instead of turning continuously.
What I have checked & verified so far:
Motor Coils: I have physically verified the motor phases using a jumper wire to check for resistance/magnetic braking. The coils are definitely correctly paired and plugged into the 2B-2A-1A-1B headers on the RAMPS board.
Driver Orientation: I verified that the DRV8825 drivers are seated properly and oriented correctly on the RAMPS board (potentiometer facing away from the green power connector).
Current Limiting (VREF): I calibrated the current using the datasheet formula for my specific drivers (RS=0.1Ω):
I = V / (5*R) (i tryed even with 8. “5” is from the driver sheet)
Given the 1.5A rating of the motors, I aimed for a safe VREF around 0.75. I have also experimented with lowering and raising the VREF slightly, but the stuttering behavior remains exactly the same.
Testing Code: I used a dead-simple, non-blocking test sketch to rotate the motor exactly 90° (50 full steps). I have tried altering the code with both longer and shorter step pulse delays (e.g., delay(2); up to delay(20);), but changing the speed doesn't fix the erratic back-and-forth oscillation.
I also tried with and eithout jumpers. With jumpers no rotation at all just buzzing without jumpers rotation but strange movements.
The Pins I am using in my code:
I am starting to wonder if the default RAMPS pinouts I found online might be wrong or different for my specific board revision. Here are the pins I am currently declaring:
#define X_STEP_PIN 54
#define X_DIR_PIN 55
#define X_ENABLE_PIN 38
#define Y_STEP_PIN 60
#define Y_DIR_PIN 61
#define Y_ENABLE_PIN 56
#define Z_STEP_PIN 46
#define Z_DIR_PIN 48
#define Z_ENABLE_PIN 62
#define EO_STEP_PIN 26
#define EO_DIR_PIN 28
#define E0_ENABLE_PIN 24
#define E1_STEP_PIN 36
#define E1_DIR_PIN 34
#define E1_ENABLE_PIN 30
SOLVED
Fake drivers. Just purchased other drivers from another site and it worked.
