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Safety
A stepper motor under closed-loop control is strong, fast and quiet, which makes it easy to forget that it can pinch, spin and heat up. Five minutes here saves fingers and boards.
12–28 V DC, never moreThe motor driver’s absolute limit is not far above 28 V. A heavy load braking hard feeds energy back into the supply and can push its voltage up: with large or fast loads, use a supply that can absorb it, or add a clamp on the supply rail.
Check the polarityAt the Power terminal, pin 1 is GND, pin 2 is VIN. Check twice before switching on.
Never hot-plug the motorBreaking a coil’s current makes a voltage spike that can destroy the driver. Switch off, wait for the red LED to go out, then change the wiring.
Fuse the supplyFor each driver or group of drivers. A slow-blow fuse of about 3 A per S1 is a reasonable start.
Motion
Section titled “Motion”It energises at power-upEnable at power-up is on by default, so the S1 holds its position as soon as it starts. Turn it off under Settings → Motion if the machine must stay limp until your program enables it.
Software stops are not safety stopsEsc in Tercio Control and Stop decelerate every motor; Emergency stop switches the bridges off. Both rely on the bus and the firmware. A machine that can hurt someone needs an emergency stop switch that cuts the motor supply.
Disabled means no holding torqueAfter an emergency stop, a hard fault or a power loss, a vertical axis falls and a loaded axis moves. Use a brake or a counterweight where that matters.
Stop when the host goes quietWhen a program streams commands, set Stop if host is silent for (Settings → Protection), for example to 200 ms, so a crashed program or an unplugged cable stops the axis.
Keep clear during proceduresCalibration turns the shaft a quarter turn each way; homing runs until it finds a switch or a hard stop; auto-tune runs back and forth faster and faster until the motor slips.
Heat and handling
Section titled “Heat and handling”Hot partsThe driver chip and the motor get hot at high current. The S1 warns 10 °C before Shut down at (95 °C by default) and switches the motor off there. Give it airflow above about 1.2 A.
StaticThe boards are sensitive to static. Hold them by the edges and touch something grounded first.
The magnet collects swarfKeep metal chips and loose screws away from the underside: the encoder magnet attracts them.