ISO 21455:2018 Crane Controller Layout & Characteristics

Direction Consistency: The Core Principle

The foundation of ISO 21455:2018 is the Directional Consistency Principle — the operating direction of the controller must align with the movement direction of the controlled mechanism. For the hoisting mechanism, an upward controller action (pushing the joystick up or pressing the up button) must raise the hook, while a downward action lowers it. For the luffing mechanism, a forward controller action increases the working radius (or lowers the boom), while a backward action decreases the radius (or raises the boom). For the slewing mechanism, a leftward controller action rotates the crane's upper structure to the left (counterclockwise), and a rightward action rotates it to the right.

The standard also specifies operating directions for travel mechanisms — moving the crane travel controller to the left moves the crane bridge to the left, and to the right moves it to the right. For trolley travel, a forward controller action moves the trolley toward the boom tip, while a backward action moves it toward the tower mast. The purpose of this principle is to minimize operator errors — statistics show that when controller directions do not match mechanism movements, the error rate increases by approximately 5 to 8 times.

Controller Types and Operating Characteristics

The standard classifies controllers by operation mode. Joystick controllers feature single or multiple levers for combined motion across one to three axes. Push-button controllers assign one button per direction, suitable for simple motion control. Cross controllers provide a four-direction control panel with self-centering functionality. Joystick controllers are further divided into single-axis types (controlling one direction) and multi-axis joysticks (controlling two to three directions simultaneously); multi-axis joysticks are recommended for combined motions to improve operating efficiency.

Operating characteristics requirements — the operating force of controllers must be moderate: 5–15 N for joysticks, 3–8 N for push-buttons, and 10–30 N for foot pedals. The neutral position must feature a clear detent or self-centering function (the controller automatically returns to neutral when released). Controllers must have clear position markings, with each operating direction labeled using text or graphical symbols. For radio remote control units, function identifiers must be placed on the operation panel in a position easily visible to the operator. The standard also specifies protection ratings for controllers — IP54 minimum inside the operator cabin and IP65 for outdoor control stations.

Controller Layout and Labeling Requirements

The standard specifies the positioning of controllers — the main controller must be placed within a 30° range to the left of the operator's forward-facing position (for right-handed operation), with auxiliary controllers positioned to the right of the main controller. The Emergency Stop Button must be located within immediate reach directly in front of the operator — a red mushroom-head button with a diameter of ≥25mm that stops operation when pressed and releases by twisting. The standard also requires that controller label text height be no less than 5mm (when viewing distance is ≤500mm), with high-contrast color schemes such as white text on a black background or black text on a white background.

When multiple mechanisms are operated in combined operation, controllers must be independent of one another — the operator should be able to simultaneously control hoisting and slewing functions without interference. The joysticks on wireless remote control transmitters must feature a self-return function (automatically returning to the neutral position when released). The standard prohibits using a single controller to operate two mechanisms in the same direction simultaneously (such as combining crane bridge and trolley travel into one controller axis), preventing operational confusion. Direction labels on controllers must use durable materials that remain clearly legible after 1,000 hours of wear testing.

Safety Requirements and Test Verification

The standard imposes safety function requirements on controllers — specifically the fail-safe function — where in the event of a controller failure (such as an open circuit, short circuit, or signal loss), the controlled mechanism must automatically stop in a safe position. Controllers must also incorporate anti-accidental-operation features, requiring two-step actions for unintended operations (e.g., pressing a confirmation key before operating). Radio remote control transmitters must be equipped with an emergency stop function — the Emergency Stop Button on the transmitter must be independent of the main control circuit, directly cutting off the hoisting and control power supply when pressed.

Test verification requirements include direction consistency checks covering all operating directions (with at least 3 repetitions), controller operating force testing (measured with a force gauge under rated voltage), and endurance testing (handles rated for ≥1 million cycles, buttons for ≥500,000 cycles). All crane controllers manufactured by Kelude are designed and validated in accordance with ISO 21455:2018, ensuring operators can quickly master the controls and that operating direction always matches the direction of movement.

FAQ: Crane Controller Design & Safety Requirements