I am currently trying to learn how to control stepper motors with arduino (later i'll want to build a small cnc router).
The main trouble is with adjusting the drivers voltage.
I have the following setup : - arduino mega 2560 + RAMPS 1.4 shield + DRV8825 drivers - 3 stepper motors with the following specifications Step Angle 1.8° Step Accuracy 5% Holding Torque 59Ncm(83.6oz.in) Rated Current/phase 2.0A Phase Resistance 1.4ohms Voltage 2.8V Inductance 3.0mH±20%(1KHz)
- using an ATX power supply for PC
What software would be recommended for these components? So far I have tried two different ways:  Repetier firmware flashed on arduino , with RepHost application on PC  GrblForCyclone firmware flashed on Arduino , with Easel application on PC .
Do you have any better suggestions about what software to use for my components ?
First of all : is it normal that the drivers voltage needs to be changed depending on which firmware that is flashed on the Arduino ?
When using Repetier firmware and RepHost application , I was able to find a setting where the X axis worked. The Y and Z axis not working at all.
But then I installed GrblForCyclone firmware . And the motors started to buzz immediately after powering up. I decreased the drivers voltage ; motors no longer buzzing . At some point the X axis worked.
But then, when going back to flash Repetier : none of the motors moved. I adjusted again the drivers voltage until I was able to make the X move again. But Y motor not moving at all. The Z axis moving only a little bit.
When trying to measure the voltage , I have : - 0.48V for X ( this is the motor that works) - 0.70V for Y (doesn't work. If I increase it , at some point it begins to vibrate and buzz). - 1.4V for Z (this is the motor that moves, but it moves less compared to the X . Maybe the Repetier software handles the Z differently.)
Shouldn't it be normal that the Y-axis driver behaves like X-axis if i set to the same 0.48V ? But for 0.48V it doesn't do anything.
Apparently it is possible to rotate forever in both directions. Is there any rule about when to stop rotating the knob clockwise and counterclockwise?
Frankly I don't really understand how to apply in practice the formula "Current Limit = VREF × 2" that is given on the polulu website .