Digital current control

Boards based on Smoothie use digital potentiometers instead of manual potentiomenters.

Instead of using a screwdriver to set the current value for the stepper motor driver ( which can be quite imprecise ), you simply set the value in the configuration file.

These are the names of the different stepper motors/drivers, and the corresponding values to change :

Label on the Smoothieboard M1 M2 M3 M4 M5
Axis in a cartesian machine X ( left-right ) Y ( front-back ) Z ( up-down ) E0 : First extruder E1 : Second extruder
Greek letter α ( alpha ) β ( beta ) γ ( gamma ) δ ( delta ) ε ( epsilon )
Current setting configuration option alpha_current beta_current gamma_current delta_current epsilon_current

The value is in Amperes, and is generally found on the motor itself, or in it's datasheet.

You can find and set these values in the configuration file.

They are found near the other values for a given axis, for example :

beta_step_pin                                2.1              # Pin for beta stepper step signal
beta_dir_pin                                 0.11             # Pin for beta stepper direction
beta_en_pin                                  0.10             # Pin for beta enable
beta_current                                 1.5              # Y stepper motor current
beta_max_rate                                30000.0          # mm/min

External ressources