US3646552A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tamperproof resistance-sensing supervisory system
Assignee: Motors Liquidation Co
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Filing: 1970-11-10
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Granted: 1972-02-29
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Expires: 1990-11-10
Abstract
Abstract A supervisory system is provided for monitoring a plurality of remote stations from a central station. A supervisory circuit located at each of the remote stations is connected to a corresponding monitoring circuit located at the central station through a pair of conductors. The supervisory circuits each include a switching device operable between an opened position and a closed position. A control circuit located at the central station and connected to each of the monitoring circuits detects closed-switch, opened-switch, ground, short circuit and open circuit conditions existing in each of the supervisory circuits located at the remote stations. In addition, the control circuit detects the failure of any of the system components and the external application of an unauthorized voltage across any of the supervisory circuits.
Inventors
- 👤 David R Fuhr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:56
CPC Classifications
G; G08; G08C; G08C19/00; G08C19/02; G08C19/025; G08B; G08B29/00; G08B29/02; G08B29/06; G08B29/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
326 words
A supervisory system for monitoring a plurality of remote stations from a central station located away from the remote stations, comprising: a plurality of supervisory circuits each located at a different one of the remote stations, the supervisory circuits each including a switching device operable between an opened position and a closed position, a first sensing resistance connected in series with the switching device, and a second sensing resistance connected in parallel with the switching device; a plurality of monitoring circuits each located at the central station, the monitoring circuits each including at least two detecting resistances connected in series, and voltage control means selectively operable between a first position in which a supply potential is applied to the detecting resistances and a second position in which a reference potential is applied to the detecting resistances; a plurality of different pairs of conductors each connecting a different one of the supervisory circuits across one of the detecting resistances of a different associated one of the monitoring circuits thereby to establish a signal voltage across the other end of the detecting resistances, the level of the signal voltage responsive to the condition of the supervisory circuit when the voltage control means is in the first position and responsive to the application of an unauthorized voltage across the supervisory circuit when the voltage control means is in the second position; and a control circuit located at the central station and connected to each of the monitoring circuits for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control means is in the first position thereby to indicate the condition of the associated one of the supervisory circuits and for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control means is in the second position thereby to indicate the application of an unauthorized voltage across the associated one of the supervisory circuits.
Claim 2
Dependent Claim
326 words
A supervisory system for monitoring a plurality of remote stations from a central station located away from the remote stations, comprising: a plurality of supervisory circuits each located at a different one of the remote stations, the supervisory circuits each including a switching device operable between an opened position and a closed position, a first sensing resistance connected in series with the switching device, and a second sensing resistance connected in parallel with the switching device; a plurality of monitoring circuits each located at the central station, the monitoring circuits each including at least two detecting resistances connected in series, and voltage control means selectively operable between a first position in which a supply potential is applied to the detecting resistances and a second position in which a reference potential is applied to the detecting resistances; a plurality of different pairs of conductors each connecting a different one of the supervisory circuits across one of the detecting resistances of a different associated one of the monitoring circuits thereby to establish a signal voltage across the other end of the detecting resistances, the level of the signal voltage responsive to the condition of the supervisory circuit when the voltage control means is in the first position and responsive to the application of an unauthorized voltage across the supervisory circuit when the voltage control means is in the second position; and a control circuit located at the central station and connected to each of the monitoring circuits for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control means is in the first position thereby to indicate the condition of the associated one of the supervisory circuits and for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control means is in the second position thereby to indicate the application of an unauthorized voltage across the associated one of the supervisory circuits.
Claim 3
Dependent Claim
373 words
A supervisory system for monitoring a plurality of remote stations from a central station located away from the remote stations, comprising: a plurality of supervisory circuits each located at a different one of the remote stations, the supervisory circuits each including a switching device operable between an opened position and a closed position, a first sensing resistor connected in series with the switching device and a second sensing resistor connected in parallel with the switching device; a plurality of monitoring circuits each located at the central station, the monitoring circuits each including at least two detecting resistors connected in series, and a voltage control switch selectively operable between a first position in which a supply potential is applied to the detecting resistors and a second position in which a reference potential is applied to the detecting resistors; a plurality of different pairs of conductors each connecting a different one of the sUpervisory circuits across one of the detecting resistors of a different associated one of the monitoring circuits thereby to establish a signal voltage across the other end of the detecting resistors, the signal voltage assuming different levels on one side of the reference potential when the voltage control switch is in the first position in response to opening of the switching device, closing of the switching device, open circuiting of one of the conductors, grounding of one of the conductors, and short circuiting of the conductors, and the signal voltage assuming a level on the other side of the reference potential when the voltage control means is in the second position in response to the application of an unauthorized voltage across the supervisory circuit; and a control circuit located at the central station and connected to each of the monitoring circuits for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control switch is in a first position thereby to indicate the condition of the associated one of the supervisory circuits and for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control switch is in the second position thereby to indicate the application of an unauthorized voltage across the associated one of the supervisory circuits.
Claim 4
Dependent Claim
373 words
A supervisory system for monitoring a plurality of remote stations from a central station located away from the remote stations, comprising: a plurality of supervisory circuits each located at a different one of the remote stations, the supervisory circuits each including a switching device operable between an opened position and a closed position, a first sensing resistor connected in series with the switching device and a second sensing resistor connected in parallel with the switching device; a plurality of monitoring circuits each located at the central station, the monitoring circuits each including at least two detecting resistors connected in series, and a voltage control switch selectively operable between a first position in which a supply potential is applied to the detecting resistors and a second position in which a reference potential is applied to the detecting resistors; a plurality of different pairs of conductors each connecting a different one of the sUpervisory circuits across one of the detecting resistors of a different associated one of the monitoring circuits thereby to establish a signal voltage across the other end of the detecting resistors, the signal voltage assuming different levels on one side of the reference potential when the voltage control switch is in the first position in response to opening of the switching device, closing of the switching device, open circuiting of one of the conductors, grounding of one of the conductors, and short circuiting of the conductors, and the signal voltage assuming a level on the other side of the reference potential when the voltage control means is in the second position in response to the application of an unauthorized voltage across the supervisory circuit; and a control circuit located at the central station and connected to each of the monitoring circuits for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control switch is in a first position thereby to indicate the condition of the associated one of the supervisory circuits and for determining the level of the signal voltage provided by each of the monitoring circuits when the voltage control switch is in the second position thereby to indicate the application of an unauthorized voltage across the associated one of the supervisory circuits.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |