Emergency Stop Categories (IEC 60204-1) — 2D

A single-joint robot arm sweeps back and forth under motor control, a payload mounted at its tip, shown here as a 2D side-on schematic with a live strip chart beneath it. Press the E-stop button at any moment and watch the arm respond according to the selected stop category: Category 0 cuts power instantly and lets gravity and inertia decide where the arm ends up; Category 1 brakes to a stop at a bounded deceleration and then removes power, letting the arm sag afterward with no holding torque; Category 2 brakes the same way but keeps the drive energised so the arm holds its exact stopping angle. Live readouts and the scrolling ω(t)/θ(t) chart track angular speed, elapsed stop time, the angle travelled while braking, and any post-stop drift, making the safety trade-off between speed of de-energisation and positional predictability directly visible.