Patent ID: 8839052

Claim:
A signal transmission device for elevator comprising: a slave node to which information showing a state of a switch or a sensor concerning control of safety of an elevator is inputted; and a master node that controls an operation of said elevator, in which one of said slave node and said master node transmits data about the safety of said elevator via a communication network and the other one of said slave node and said master node receives the data via the communication network, wherein each of said slave node and said master node includes a safety data processing unit and a communication processing unit, and the safety data processing unit and the communication processing unit included in each node operate in parallel with each other, said safety data processing unit in the slave node acquires said data about the safety at fixed time intervals and also adds an error detecting code which can achieve a predetermined rate of overlooking errors to create first data, and outputs the first data to said communication processing unit in the slave node, said safety data processing unit in the master node checks whether or not said error detecting code of said first data outputted from said communication processing unit in the slave node is correct and analyzes a state concerning the safety of said elevator on a basis of said data about the safety acquired from the first data in which no error is detected, and said communication processing unit in the slave node creates second data including said first data outputted from said safety data processing unit in the slave node, and transmits said second data via said communication network a predetermined number of times, and when properly receiving one or more pieces of said second data having a same content, said communication processing unit in the master node determines one of the one or more pieces of said second data as effective second data, and outputs the first data to said safety data processing unit in the master node, and wherein the safety data processing unit in said master node stops the elevator when detecting an error from the error detecting code of the first data inputted from the communication processing unit in the master node or when said master node cannot receive said first data during a certain period of time.