The safety PLC manages the risks of contacts between the retractable catenary and maintenance agents and mobile equipment such as overhead cranes, retractable extractors, cherry pickers, bridging plates or trainset hoisting head frame.
Defining areas where the position of tools is set with magnetic switches attached to the crane, and inductors attached to the trolley.
Inductors are made up of high coercity, permanent magnets coated with plastic that is inert to common agents. Magnets are highly stable and immune to vibrations.
The switch, when it comes near an inductor, switches the electric contacts, and keeps them in that position. The return of the inductor in the opposite direction replaces the magnets, the contacts in their initial positions.
This simple, robust device is made up of a magnetic circuit and a dynamically balanced mobile element, actuating 2 two-way electric contacts and maintained by the attraction of two internal permanent magnets. The switches polarised by this setting, only work under the influence of an external magnetic field of a specific direction and magnitude. The contact mechanisms set is contained in a perfectly sealed enclosure.
By their very nature, magnetic switches require no power source. They are therefore insensitive to power failures, they keep their positions in memory.
They remove mechanical movements take-offs, which are subject to wear.
They cannot be tampered with using external mechanical force.
They require no maintenance.
The information obtained by the travelling of inductors, are managed by a safety PLC module, located on the overhead crane.
This module dialogues with the safety PLC's CPU, located in the catenary cabinet via a multitrack rail or reeler.