Bsmce04u-pp Manual -

Used to drive external relays (e.g., mist, flood, spindle start). Spindle Speed

The (often labeled as a Bitsensor or RNR Eco-Motion card) is a popular, budget-friendly 4-axis USB motion control card for CNC machines. Reviewing its documentation reveals a product that is highly functional for its price point but suffers from a notoriously steep learning curve due to fragmented or missing official manuals. Documentation & Accessibility bsmce04u-pp manual

: These are used for limit switches and E-stops. They are typically triggered by connecting the pin to the DCM (Digital Ground). Used to drive external relays (e