How to adjust current via VREF on Creality Mainboards

TABLE OF CONTENTS

• Written Guide: 
  • How to change the Current using Vref
  • Example:
• Video Guide: 

Written Guide: 

How to change the Current using Vref

Reading the current supplied to stepper motors can be challenging. To determine this current, we utilize the Vref value, a voltage reference measured in VDC, which can be obtained using a multimeter. This value is crucial for setting the output current of the stepper motor driver.

Different 3D printer mainboards employ various stepper motor drivers, and each type has its own formula for calculating the required Vref to achieve a specific current. Here are a couple of examples:

• TMC stepper drivers.
  The formula for these drivers is Vref = ( I * 2.5 ) / Imax
  Where I is the target current value measured in A; and Imax is 1.77 on regular mode and 1.2 on SilentStepSticks mode.

• Pololu A4998.
  The formula for these drivers is Vref = I * 8 * R
  Where I is the target current value measured in A; and R is the Sense Resistor value, that depends on what board are you using. Melzis use 0.1,the Creality Silent boards use 0.15, ...

Example:

For a desired current of 0.5A, the resulting Vref would be 0.6V on a Creality A4998 board.

0.5 * 8 * 0.15=0.6

Video Guide: