Title:
INTRINSICALLY SAFE DEVICE OF SENSOR
Document Type and Number:
Japanese Patent JPH0560583
Kind Code:
A
Abstract:
PURPOSE:To prevent application of abnormal voltages to a signal processing circuit even if a commercial power supply is connected by mistake to output terminals by connecting a plurality of blocking diodes in series to positive terminals, and shortcircuiting a circuit between the positive and negative terminals and from the negative terminals toward the positive terminals. CONSTITUTION:In case the voltage of a commercial power supply 1 is applied to the terminal of the output circuit of a sensor 14, application of the voltage to a sensor circuit is prevented by blocking diodes 26, and even if one of the diodes 26 fails, the sensor circuit is protected by the other diodes. Also when a AC positive half-wave is applied between the negative terminals 28 of the output circuit and toward the negative terminals, the circuit is shortcircuited from the negative terminals 28 toward positive terminals 27 by protecting diodes 31, and even if one of the diodes 31 fails, the circuit is protected by the other diodes. Or when a protecting transistor 2 fails the sensor circuit is protected by Zener diodes 22 and even if one of the diodes fails the sensor circuit is protected by the other diodes.
Inventors:
ICHIDA SHUNJI
Application Number:
JP29859391A
Publication Date:
March 09, 1993
Filing Date:
August 30, 1991
Export Citation:
Assignee:
YAMATAKE HONEYWELL CO LTD
International Classes:
G01D3/00; G01D21/00; G01N27/04; (IPC1-7): G01D3/00; G01D21/00; G01N27/04
Attorney, Agent or Firm:
Hiroaki Tazawa (2 outside)
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