The manual includes a formula similar to: Vref = Motor Current (Amps) / 2 Or for A4988: Vref = Current Limit

: While the board itself is reliable, users often report that the entry-level machines it controls (like the standard CNC 3018) lack rigidity for anything beyond soft wood, foam, or plastic. Upgrade Capability : The board supports various upgrades, including 500W spindles laser modules

Some boards use a jumper to switch between Laser PWM and Spindle power. AliExpress Setup and Software