Safety Control of Power Press by Using Fail-Safe Multiple-Valued Logic

Masayoshi SAKAI  Masakazu KATO  Koichi FUTSUHARA  Masao MUKAIDONO  

IEICE TRANSACTIONS on Information and Systems   Vol.E76-D   No.5   pp.577-585
Publication Date: 1993/05/25
Online ISSN: 
Print ISSN: 0916-8532
Type of Manuscript: Special Section PAPER (Special Issue on Multiple-Valued Logic)
Category: Fail-Safe/Fault Tolerant
fault tolerance,  multiple-valued logic,  fail-safe,  threshold operation,  power press control,  

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This paper first clarifies the logic construction of safety control for the operation of a power press and then describes fail-safe dual two-rail system signal processing and fail-safe multiple-valued logic operations as methods for achieving this control as a fail-safe system. It finally shows a circuit for generating fail-safe two-rail run button signals based on ternary logic for concrete operation of the power press 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 binary logic signals that do not erroneously go logic 1 are added to a multiple-valued logic signal and the multiple-valued logic signal is converted to a binary logic signal that does not erroneously go logic 1 by a threshold operation.