SAFETY CONTROL OF POWER PRESS BY USING FAIL-SAFE MULTIPLE-VALUED LOGIC

This paper first clarifies the logic construction of safety control fo r the operation of a power press and then describes fail-safe dual two -rail system signal processing and fail-safe multiple-valued logic ope rations as methods for achieving this control as a fail-safe system. I t finally shows a circuit for generating fail-safe two-rail run button signals based on ternary logic for concrete operation of the power pr ess and an operation control circuit for confirming brake performance for each cycle of slide operation by using the run button signals. The control circuit uses such multiple-valued logic operations that binar y logic signals that do not erroneously go logic 1 are added to a mult iple-valued logic signal and the multiple-valued logic signal is conve rted to a binary logic signal that does not erroneously go logic 1 by a threshold operation.