Title:
ON-LINE DIAGNOSTIC METHOD AND DEVICE FOR FAIL-SAFE SWITCH
Document Type and Number:
Japanese Patent JP3630583
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To attain the on-line diagnosis of a fail-safe switch for normally interrupting current supply by a 'emergency stop' or 'fail-safe' command through a conductive field effect transistor(FET) or the like.
SOLUTION: An on-line diagnostic device for a fail-safe switch (FET) 10 for supplying current normally from an AC power supply 2 to an equipment 7 and interrupting current supply to the equipment 7 when an 'emergency stop' or 'fail-safe' control command is outputted from a controller or the like is provided with a detection circuit 20 for detecting the load current of the equipment 7, a diagnostic timing generation circuit 30 for generating a diagnostic pulse for controlling the FET 10 to an off state at timing for outputting '1' when a detection value V (converted into a voltage value) from the circuit 20 exceeds a prescribed reference (Ref) and a judgment circuit 44 for comparing a held detection value Vhold held at the timing and a detection value V detected immediately after the value Vhold, and when Vhold ≥ V, judging the off of the FET 10.
Inventors:
Takashi Kitada
Hisao Nagayama
Sota Kusmoto
Kuniyuki Inokari
Shuichi Nakamichi
Hisao Nagayama
Sota Kusmoto
Kuniyuki Inokari
Shuichi Nakamichi
Application Number:
JP10615899A
Publication Date:
March 16, 2005
Filing Date:
April 14, 1999
Export Citation:
Assignee:
株式会社日立製作所
株式会社 日立ハイコス
株式会社 日立ハイコス
International Classes:
G05B23/02; G05B9/02; H03K17/00; (IPC1-7): G05B23/02; H03K17/00
Domestic Patent References:
| JP8006602A | ||||
| JP9257870A |
Attorney, Agent or Firm:
Katsuo Ogawa
Akio Takahashi
Kyosuke Tanaka
Yasuo Sakuta
Katsuo Ogawa
Akio Takahashi
Kyosuke Tanaka
Akio Takahashi
Kyosuke Tanaka
Yasuo Sakuta
Katsuo Ogawa
Akio Takahashi
Kyosuke Tanaka