Designing a Safer Crane
Otay Crane Bridge
These two travelling crane bridges, controls and motors were aging and outdated and suffering from some serious safety concerns. CTI was hired to replace the controls, switches, motors and wiring and revise the logic to safeguard against safety issues.
CTI set out to modernize the control system using the latest Allen Bradley products to increase the longevity of the system as well as create a user-friendly graphical interface. Error Prone mechanical limit switches were replaced with high-end proximity switches to eliminate the mechanical failure. A 12 inch graphical interface was installed with a fully custom graphics and touch screen for increased usability. In the event of screen failure, manual buttons added to the system would allow full functionality. Several fail-safes were designed to address the safety issue. First, an interlock was written into the PLC code which would not allow the bridge to travel with the arm extended, ever. An overtorque monitoring fault was created so that, in the even of a spike in AMPS, the equipment will fault immediately. This interlock limits the ability of the crane to physically damage itself. Incandescent lighting was replaced with LED. A new stainless steel panel door was provided, along with a stainless steel extra-narrow 1800 BTU air conditioner. Motors were replaced with identical units.