Modes and units

Units

servolab always uses SI units.

Value	Unit
position	rad, 0 = middle of the motor, −π … +π
velocity	rad/s
current	A
voltage	V
temperature	°C
load, PWM	−1.0 … 1.0 (1.0 = 100 %)
IMU acceleration	m/s² (includes gravity)
IMU angular velocity	rad/s
IMU orientation	quaternion [w, x, y, z]

Raw register values (m.read_register(...), the Settings section in ServoScope) are the motor's own integers. The unit column tells you what one step means.

Modes

Mode	You set	The motor …
position	m.position	moves to the goal and holds it (internal PID)
velocity	m.velocity	turns at the goal speed (internal speed controller)
pwm	m.pwm	gets this fraction of the supply voltage – no controller, that's your job

Switch with m.mode = "velocity". servolab makes the switch safe: the motor stays where it is (position), starts at 0 rad/s (velocity) or at 0 % PWM.

A command that does not fit the mode is refused with a hint, e.g. setting m.velocity while the motor is in position mode.

Saving settings

Settings like mode, limits and gains live in the motor's EEPROM area. When you change them, they work immediately but are lost after power-off. To keep them:

m.write_register("p_coefficient", 20, save=True)   # one value
m.save_to_eeprom()                                 # everything

Don't save in a loop: EEPROM wears out after many writes.