Electricity: measuring and testing – Electrical speed measuring – Speed comparing means
Patent
1996-12-06
1998-06-30
Strecker, Gerard R.
Electricity: measuring and testing
Electrical speed measuring
Speed comparing means
324166, 324537, 324772, 318799, 340648, 340671, 361242, G01P 1300, G01P 300, G01R 3100, G08B 1900
Patent
active
057739722
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP96/00585 filed Mar. 8, 1996.
FIELD OF THE INVENTION
The present invention relates to a transition detection circuit that detects completion of a transition (no transition) in the state of an object of detection. The transition detection circuit according to the present invention may be widely adopted in safety related apparatuses. As a typical example of application, an apparatus that detects stoppage of rotation of a moving part, for instance, can be cited.
DISCUSSION OF THE BACKGROUND
A technology with which stoppage of a moving part is detected in a fail safe manner and distinguished from rotation under inertia is disclosed in, for instance, International Publication No. WO94/23303. Also, International Patent Application PCT/JP95/00165 discloses a technology for detecting in a fail safe manner that a moving part is rotating at or below a specific rotation rate.
International Publication No. WO94/23303 discloses a motor rotation stoppage verifying apparatus that is capable of reliably detecting that the rotation of a motor has stopped, including rotation under inertia, and operates toward safety when a failure has occurred in the apparatus, to provide a high degree of safety. However, since this apparatus in the prior art is not provided with a function for detecting the rotation rate, there are problems such as a delay in notification of stoppage and the need for adjustment of a bridge circuit that is employed in the rotation sensor.
International Patent Application PCT/JP95/00165 discloses a means for solving these problems. However, while the method disclosed in International Patent Application PCT/JP95/00165 is suitable for a case in which a coil is employed as a means for rotation detection, the publication does not disclose a general circuit structure suited to be used in various means for detection. In addition, it does not disclose a means for protection against drop-off of a transducer that determines rotation while a rotating body is in a stopped state.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a transition detection circuit that detects the completion of a transition (no transition) in the state of an object of detection in a fail safe manner while taking into consideration the possibility of an error in the means for detection or a circuit.
In order to achieve the object described above, the transition detection circuit according to the present invention includes a detector, a first state detection circuit, a second state detection circuit and a state judgement circuit. The detector outputs a signal that corresponds to the operation characteristics of an object of detection. These operation characteristics include a transition from a first state to a second state.
The first state detection circuit generates a first output signal that corresponds to the first state based upon a signal provided by the detector. The second state detection circuit generates a second output signal that corresponds to the second state based upon the signal provided by the detector. When the object of detection shifts from the first state to the second state in a normal manner, there is a period of time during which the first output signal and the second output signal are both at a high level.
The state judgement circuit generates a state judgement output signal on condition that there has been a period of time during which the first output signal and the second output signal were both at a high level.
According to the present invention, the only requirement imposed upon the object of detection is that it posseses operation characteristics that include a shift from a first state to a second state. Typical examples would be an object that undergoes a displacement such as a rotating body, a moving body and the like and an object that shifts from a first state to a second state in response to a change in pressure, temperature or the like.
Transition detection in regard to such an object of detection normally refers to detecting the completio
REFERENCES:
patent: 3932812 (1976-01-01), Milligan
patent: 4013945 (1977-03-01), Groso
patent: 4763054 (1988-08-01), Bundy
patent: 5451867 (1995-09-01), Loreck et al.
Futsuhara Koichi
Shirai Toshihito
Strecker Gerard R.
The Nippon Signal Co. Ltd.
LandOfFree
Transition detection circuit for detecting transitions in the st does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Transition detection circuit for detecting transitions in the st, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Transition detection circuit for detecting transitions in the st will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1863644