PARALLEL OUTPUT TYPE ELECTRONIC INTERLOCKING SYSTEM FURNISHED WITH FAIL SAFE MAJORITY LOGIC CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a fail safe majority logic circuit not to output false output on the dangerous side even at the time when a single failure occurs by discovering the single failure at an early stage. SOLUTION: The fail safe majority logic circuit to find a majority of at least three pieces of logic input is constituted by a circuit to compose the two input each of the three input of three pieces of OR circuits 311∼313 and to compose output of these OR circuits by a three input AND circuit 321. Additionally, a control mode and a failure detection mode are set in the circuit, a pattern for failure detection is input at the time of the failure detection mode and a failure of a part constituting the circuit is detected by absorbing the output. The input is forcibly changed so that the output of the circuit does not output to the dangerous side in the case of detecting the failure. Safety of the electronic interlocking device is improved by applying this fail safe majority logic circuit to the electronic interlocking device. COPYRIGHT: (C)2004,JPO