Title:
【発明の名称】接点データ読み込み回路
Document Type and Number:
Japanese Patent JPH0786522
Kind Code:
B2
Abstract:
PURPOSE:To easily recognize the opening/closing state of a contact and the generation of disconnection of a transmission circuit by connecting in parallel the output sides of two pieces of photocouplers to the capacity of a resistance capacity series circuit and monitoring a voltage level of the capacity by using a logical gate. CONSTITUTION:In a transmission circuit 3, input sides of two pieces of photocouplers 71, 72 are connected in the forward direction to a diode 2, respectively. Two pieces of resistance capacity series circuits consisting of a resistance 81 and a capacity 91, and a resistance 82 and a capacity 92 are connected in parallel to each other. In this state, when a contact 1 is closed, half-wave rectifying currents in the forward direction and in the backward direction are allowed to flow a photocoupler 71 and a photocoupler 72, respectively and the photocouplers 71, 72 are turned on alternately, and when the contact 1 is opened, only the half-wave rectifying current in the forward direction is allowed to flow to the transmission circuit 3 through the diode 2, only the photocoupler 71 is turned on periodically, and when the transmission circuit 3 is disconnected, both the photocouplers 71, 72 are turned off. By discriminating a voltage level of the capacity of two pieces of resistance capacity series circuits of the output side to said three states through logical gates 10, 11, the generation of disconnection is recognized.
Inventors:
Kazuhisa Inoue
Application Number:
JP23374987A
Publication Date:
September 20, 1995
Filing Date:
September 19, 1987
Export Citation:
Assignee:
Yaskawa Electric Co., Ltd.
International Classes:
G01R31/00; G01R31/02; (IPC1-7): G01R31/00; G01R31/02
Domestic Patent References:
| JP5612560A | ||||
| JP55175879U |
Attorney, Agent or Firm:
Wakabayashi Tadashi
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