Elevator safety control device, method for elevator safety control and elevator system

An elevator system comprising:

• a car;
• a non-safety function unit of an elevator;
• a first safety switch;
• a second safety switch comprising a plurality of landing door switches whose status can be determined individually;
• a holding brake device;
• and
• an elevator safety control device comprising:
• an interface unit configured to receive a first status signal of the first safety switch, a second status signal of the second safety switch, and a third status signal of the non-safety function unit of the elevator;
• a safety controller configured to perform the following operations:
• determining an occurrence of an abnormal event based on the first status signal, the second status signal and the third status signal;
• determining, after determining the occurrence of the abnormal event, a possibility of the car stopping at a landing door of the nearest floor based on the second status signal;
• and
• executing a rescue mode after determining an existence of the possibility, wherein in the rescue mode, the car is caused to travel by gravity and stop at the landing door of the nearest floor by controlling a state of the holding brake device.

A method for elevator safety control comprising:

• receiving a first status signal of a first safety switch, a second status signal of a second safety switch, and a third status signal of a non-safety function unit of an elevator, wherein the second safety switch comprises a plurality of landing door switches whose status can be determined individually;
• determining an occurrence of an abnormal event based on the first status signal, the second status signal and the third status signal;
• determining, after determining the occurrence of the abnormal event, a possibility of a car stopping at a landing door of the nearest floor based on the second status signal;
• and
• executing a rescue mode after determining an existence of the possibility, wherein in the rescue mode, the car is caused to travel by gravity and stop at the landing door of the nearest floor by controlling a state of a holding brake device.