I was asked to design an interlocking system on the lift gates of each floor. The functions are that: The gates cannot be opened when the lift motor is moving; The motor must be stopped when any gate is opened; The gate of one floor can be opened when the lift cage is leveled on that floor too. I have designed the circuit but cannot ensure whether it is correct ot not. Could you mind to check for me? And give me some advices about it. The circuit is posted on follow webpage: http://hk.geocities.com/ericyan929/docu0012.jpg Thanks a lot.