Safety switch for controlling the access to industrial machines or plants

A switch assembly for controlling access to a machine or industrial plant, comprising a plurality of safety switches, each safety switch comprising:

• a switching device adapted to be associated with a fixed part of the access to be controlled and operably connectable to one or more control and/or service circuits of the plants for controlling thereof;
• an actuator device associated with a movable part of the access to interact with said switching device at the opening/closing of the access for opening/closing one or more of said circuits and passing from a removed condition to an inserted condition;
• a lock housed in said switching device and adapted to lock said actuator device on said switching device following their mutual interaction;
• an electronic control circuitry having a first communication channel with a first inlet and a first outlet and a second communication channel with a second inlet and a second outlet, said communication channels being adapted to receive and transmit information about the locked and open conditions of the accesses according to the state of the corresponding actuator device;
• wherein said first inlet and said second outlet are of safe type and adapted to vary their state after detecting said removed/inserted and/or locked condition of said actuator device;
• wherein said electronic control circuitry is adapted to vary the state of said first outlet and said second outlet upon detection respectively of a first and a of second condition for said actuator device, wherein said first and said second conditions are different from each other,
• wherein said safety switches have respective inlets and outlets;
• wherein each of said safety switches has respective outlets connected in series with the inlets of the switch arranged downstream.