US4603318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Telemetry and like signaling systems
Assignee: Individual
•
Filing: 1983-11-14
•
Granted: 1986-07-29
•
Expires: 2003-11-14
Abstract
Abstract A system for sensing multiple conditions, such as alarm conditions, at each of a number of remote stations, the sensing being accomplished solely through a pair of power lines by means of which the remote stations are connected in a cascade arrangement with a central station. When power is applied to the first of the remote stations, a current pulse is drawn through the power lines and is modulated in accordance with a sensed condition at the remote station. At the end of the current pulse, there is at least one zero-current interval, the duration of which is varied in accordance with another sensed condition at the remote station. The central station, after applying power to the first remote station, identifies the sensed conditions from the modulated current pulses and the durations of the zero-current intervals. Each remote station also includes a line power switch that remains open until the completion of interrogation of the sensed conditions at that particular station. Then the line power switch is closed and power is transmitted to the next remote station in sequence. Additional features disclosed include the use of power for secondary purposes during zero-current intervals, the detection of cumulative sensor activity at a remote station, and a power-seeking line switch to permit remote stations to receive power from either direction.
Inventors
- 👤 Robert J. Philp
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:51
CPC Classifications
G; G08; G08B; G08B26/00; G08B26/005
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
153 words
A signaling system for monitoring a plurality of conditions at each of a plurality of remote sites, said system comprising: a central station; a plurality of remote stations connected in a cascaded relationship to said central station by a single pair of power lines and adapted to receive electrical power from said central station, each of said remote stations including means for modulating a current pulse passing through said power lines, in accordance with a first sensed condition, means for varying the duration of a zero-current interval following said current pulse, in accordance with a second sensed condition, and switching means for selectively transmitting power to the next remote station connected to said power lines; and wherein said central station includes means for counting current pulses on said power lines, and means for determining the sensed conditions at the remote sites, from the modulated current pulses and the durations of the zero-current intervals.
Claim 2
Dependent Claim
153 words
A signaling system for monitoring a plurality of conditions at each of a plurality of remote sites, said system comprising: a central station; a plurality of remote stations connected in a cascaded relationship to said central station by a single pair of power lines and adapted to receive electrical power from said central station, each of said remote stations including means for modulating a current pulse passing through said power lines, in accordance with a first sensed condition, means for varying the duration of a zero-current interval following said current pulse, in accordance with a second sensed condition, and switching means for selectively transmitting power to the next remote station connected to said power lines; and wherein said central station includes means for counting current pulses on said power lines, and means for determining the sensed conditions at the remote sites, from the modulated current pulses and the durations of the zero-current intervals.
Claim 3
Dependent Claim
86 words
A signaling system as set forth in claim 1, wherein: said means for modulating a current pulse includes timing means responsive to said first sensed condition, for varying the duration of said current pulse drawn from said central station upon initial application of electrcal power from said central station to said remote station; and said switching means is responsive to said means for varying the duration of said zero-current interval, to apply power to the next remote station in sequence upon completion of said zero-current pulse.
Claim 4
Dependent Claim
52 words
A signaling system as set forth in claim 2, wherein: said first sensed condition is a binary condition that results in one of two possible pulse lengths of the current pulse; and said second sensed condition is another binary condition that results in one of two possible durations of the zero-current interval.
Claim 5
Dependent Claim
76 words
A signaling system as set forth in claim 3, wherein said central station includes: means for generating a reset signal on the power lines, to reset said remote stations to an initial state; means for applying electrical power to a first of said remote stations via said power lines; and means for measuring the durations of successive current pulses and zero-current intervals in said power lines, and thereby interrogating the sensed conditions at said remote stations.
Claim 6
Dependent Claim
59 words
A signaling system as set forth in claim 1, wherein said means for determining the sensed conditions at the remote sites includes: means for detecting and locating a line short-circuit condition, from the occurrence of an excessively long current pulse; and means for detecting and locating a line open-circuit condition, from the occurrence of an excessively long zero-current interval.
Claim 7
Dependent Claim
44 words
A signaling system as set forth in claim 1, wherein each of said remote stations further includes: bistable switching means responsive to a signal from said central station, to switch electrical power from said power lines to meet a secondary function during zero-current intervals.
Claim 8
Dependent Claim
35 words
A signaling system as set forth in claim 1, wherein at least one of said remote stations further includes: transducer memory means, for storing a cumulative sensed condition between successive interrogations from said central station.
Claim 9
Dependent Claim
40 words
A signaling system as set forth in claim 1, wherein each of said remote stations further includes: power seeking switching means, with the ability to connect the remote station to a power signal from either direction in said power lines.
Claim 10
Dependent Claim
179 words
A signaling system for monitoring a plurality of conditions at each of a plurality of remote sites, said system comprising: a central station; a plurality of remote stations, each of which has at least two sensors associated with that station; a pair of power supply lines extending from said central station through each of said remote stations in a cascade arrangement; each of said remote stations including means for modulating a current pulse drawn through said power lines, in accordance with the condition of a first of said sensors, means for varying the duration of a zero-current interval following said current pulse, in accordance with the condition of a second of said sensors, switching means installed in one of said power lines, for transmitting power to the next remote station connected to said power lines, upon completion of said zero-current interval; and wherein said central station includes means for counting current pulses in said power lines, and means for determining the sensed conditions at the remote sites, from the modulated current pulses and the durations of the zero-current intervals.
Claim 11
Dependent Claim
179 words
A signaling system for monitoring a plurality of conditions at each of a plurality of remote sites, said system comprising: a central station; a plurality of remote stations, each of which has at least two sensors associated with that station; a pair of power supply lines extending from said central station through each of said remote stations in a cascade arrangement; each of said remote stations including means for modulating a current pulse drawn through said power lines, in accordance with the condition of a first of said sensors, means for varying the duration of a zero-current interval following said current pulse, in accordance with the condition of a second of said sensors, switching means installed in one of said power lines, for transmitting power to the next remote station connected to said power lines, upon completion of said zero-current interval; and wherein said central station includes means for counting current pulses in said power lines, and means for determining the sensed conditions at the remote sites, from the modulated current pulses and the durations of the zero-current intervals.
Claim 12
Dependent Claim
82 words
A signaling system as set forth in claim 9, wherein: said means for modulating a current pulse includes timing means responsive to said first sensed condition, for varying the duration of said current pulse drawn from said central station upon initial application of electrical power to said remote station; and said switching means is responsive to said means for varying the duration of said zero-current interval, to apply power to the next remote station in sequence upon completion of said zero-current interval.
Claim 13
Dependent Claim
52 words
A signaling system as set forth in claim 10, wherein: said first sensed condition is a binary condition that results in one of two possible pulse lengths of the current pulse; and said second sensed condition is another binary condition that results in one of two possible durations of the zero-current interval.
Claim 14
Dependent Claim
83 words
A signaling system as set forth in claim 11, wherein said central station includes: means for generating a reset signal on the power lines, to reset said remote stations to an initial state; means for applying electrical power via said power lines to a first of said remote stations at the start of each interrogation cycle; and means for measuring the durations of successive current pulses and zero-current intervals in said power lines, and thereby interrogating the sensed conditions at said remote stations.
Claim 15
Dependent Claim
59 words
A signaling system as set forth in claim 9, wherein said means for determining the sensed conditions at the remote sites includes: means for detecting and locating a line short-circuit condition, from the occurrence of an excessively long current pulse; and means for detecting and locating a line open-circuit condition, from the occurrence of an excessively long zero-current interval.
Claim 16
Dependent Claim
44 words
A signaling system as set forth in claim 9, wherein each of said remote stations further includes: bistable switching means responsive to a signal from said central station, to switch electrical power from said power lines to meet a secondary function during zero-current intervals.
Claim 17
Dependent Claim
35 words
A signaling system as set forth in claim 9, wherein at least one of said remote stations further includes: transducer memory means, for storing a cumulative sensed condition between successive interrogations from said central station.
Claim 18
Dependent Claim
39 words
A signaling system as set forth in claim 9, wherein each of said remote stations further includes: power-seeking switching means, with the ability to connect the remote station to a power signal from either direction in said power lines.
Claim 19
Dependent Claim
127 words
For use in a signaling system having a central station and a single pair of power supply lines extending from the central station to connect remote stations in a cascade arrangement, a remote signaling station comprising: means responsive to the application of electrical power, for drawing a current pulse from said power lines; means responsive to a first sensed condition for modulating said current pulse in accordance with said first sensed condition; timing means activated in response to termination of said current pulse, and responsive to a second sensed condition, for timing a zero-current interval in accordance with said second sensed condition; and line switching means operable only at the end of said zero-current interval, for switching power to the next of said remote stations in sequence.
Claim 20
Dependent Claim
127 words
For use in a signaling system having a central station and a single pair of power supply lines extending from the central station to connect remote stations in a cascade arrangement, a remote signaling station comprising: means responsive to the application of electrical power, for drawing a current pulse from said power lines; means responsive to a first sensed condition for modulating said current pulse in accordance with said first sensed condition; timing means activated in response to termination of said current pulse, and responsive to a second sensed condition, for timing a zero-current interval in accordance with said second sensed condition; and line switching means operable only at the end of said zero-current interval, for switching power to the next of said remote stations in sequence.
Claim 21
Dependent Claim
84 words
A remote signaling station as set forth in claim 17 wherein: said means for modulating said current pulse includes timing means responsive to said first sensed condition, for varying the duration of said current pulse drawn from said central station upon initial application of electrical power to said remote station; and said switching means is responsive to said means for varying the duration of said zero-current interval, to apply electrical power to the next remote station in sequence upon completion of said zero-current pulse.
Claim 22
Dependent Claim
53 words
A remote signaling station as set forth in claim 18, wherein: said first sensed condition is a binary condition that results in one of two possible pulse lengths of said current pulse; and said second sensed condition is another binary condition that results in one of two possible durations of said zero-current interval.
Claim 23
Dependent Claim
32 words
A remote signaling station as set forth in claim 19, and further including means responsive to a reset signal on said power lines, for resettting said signaling station to an initial condition.
Claim 24
Dependent Claim
41 words
A remote signaling station as set forth in claim 17, and further including: bistable switching means responsive to a signal on said power lines, to switch electrical power from said power supply lines to perform a secondary function during zero-current intervals.
Claim 25
Dependent Claim
25 words
A remote signaling station as set forth in claim 17, and further including: transducer memory means, for storing a cumulative sensed condition between successive interrogations.
Claim 26
Dependent Claim
33 words
A remote signaling station as set forth in claim 17, and further including: power-seeking switching means, for selectively connecting said remote station to a power signal from either direction in said power lines.
References Cited (Backward Citations)
US4093946A
Cited
US4162489A
Cited
US4206449A
Cited
US4359721A
Cited
US4491828A
Cited
US4290055A
Cited
US4385287A
Cited
US4413259A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-28 | 1990-01-27 | 1990-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-28 | 1994-01-27 | 1994-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-28 | 1998-01-27 | 1998-07-29 | $7700.00 | Window Closed / Lapsed |