High on safety
Crane controls designer NTK is providing an advanced new safety system for tower cranes, central to which is the control system based around a new generation of safety PLC from ABB.
The system continuously monitors load torque as well as working and collision areas in real time – to SIL3 (IEC 61508 and 62061) PLe (ISO 13849-1) functional safety level. It provides instant and comprehensive visibility for the operator of all key crane status indicators.
The crane’s maximum movement speed is also now controlled by a fully dynamic calculation of load moment. This enhances crane productivity by providing an infinitely adjustable hoisting performance envelope – rather than using more restrictive gradated maximum speed bands.
The safety PLC used – ABB’s AC500-S – simplified this control upgrade project because of its built-in maths capabilities. Unlike other safety controller options the PLC supports trigonometric mathematical functions, greatly speeding static and dynamic crane load safety calculations. The position of the trolley, radius of the crane, plus load and wind conditions are all displayed by NTK’s graphical touch-screen user interface.
