Title:
INTERFACE CIRCUIT
Document Type and Number:
Japanese Patent JPS60150101
Kind Code:
A
Abstract:
PURPOSE:To secure the safety to an incidental fault such as a runaway, etc. by using a gate control circuit which inactivates all photocouplers in case at least two of control signals which work reversely to each other are delivered at a time. CONSTITUTION:In case control signals C1 and C2 are delivered at a time from terminals A1 and A2 of a control unit 1 by an incidental fault and in a floating mode after resetting, outputs C1A and C2A of an AND1 and an AND2 are set at H. Therefore the output MS of an AND3 is also set at H and a transistor Q1 is turned off. Thus the collector of the Q1 is set in a floating state. Then the light emitting elements of photocouplers PC1-PC4 have no emission of light even though control signals C1-C4 are delivered and the outputs of inverters IN1-4 are set at L. Therefore the photodetecting element has no actuation either and signals S1-S4 are never delivered. In this way, malfunction or runaway of a device to be controlled is prevented.
Inventors:
TOUJIYOU TAKESHI
Application Number:
JP596084A
Publication Date:
August 07, 1985
Filing Date:
January 17, 1984
Export Citation:
Assignee:
FUJI PHOTO FILM CO LTD
FUJI MICROGRAPHICS
FUJI MICROGRAPHICS
International Classes:
G05B9/02; G05B19/048; H04L69/40; (IPC1-7): G05B9/02
Attorney, Agent or Firm:
Yuzo Agata