US4096989A
Expired / Lapsed
US
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Monitoring apparatus for redundant control systems
Assignee: Bendix Corp
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Filing: 1977-06-20
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Granted: 1978-06-27
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Expires: 1997-06-20
Abstract
Abstract Monitoring apparatus for redundant control systems includes means for preventing the monitoring apparatus from failing to a "good" state. Each of the channels in the redundant system generates a command signal which is compared to a signal provided by adding the command signal generated by another of the channels to a tracer signal. The amplitude of the addition signal is such so that the comparator toggles between its "good" and "fail" states to obviate failure of the monitoring apparatus to its "good" state.
Inventors
- 👤 David A. Tawfik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:33
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/22; H03K5/24; G; G05; G05B; G05B9/00; G05B9/02; G05B9/03; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/1629; G06F11/1633
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
114 words
Monitoring apparatus for control systems including a plurality of redundant channels; comprising: each of the channels including means for generating a command signal, means for generating a tracer signal, means for combining the command signal and the tracer signal, and comparator means; the comparator means in one channel comparing the command signal generated by the command signal generating means in the one channel to the combined command signal and tracer signal from the combining means in one of the other channels, and providing an output which toggles between the "good" and "fail" states of the comparator means in the one channel; and means responsive to the toggle output for providing a failure logic output.
Claim 2
Dependent Claim
114 words
Monitoring apparatus for control systems including a plurality of redundant channels; comprising: each of the channels including means for generating a command signal, means for generating a tracer signal, means for combining the command signal and the tracer signal, and comparator means; the comparator means in one channel comparing the command signal generated by the command signal generating means in the one channel to the combined command signal and tracer signal from the combining means in one of the other channels, and providing an output which toggles between the "good" and "fail" states of the comparator means in the one channel; and means responsive to the toggle output for providing a failure logic output.
Claim 3
Dependent Claim
56 words
Apparatus as described in claim 1, wherein: the comparator means in the one channel having a predetermined threshold; and the combined signal from the one of the other channels having an amplitude which is twice said comparator means threshold for tripping the comparator means at a 50 percent duty cycle between its "good" and "fail" states.
Claim 4
Dependent Claim
28 words
Apparatus as described by claim 1, wherein: the combined signals from each of the channels are alternating signals; and each of the combined signals has a different frequency.
Claim 5
Dependent Claim
29 words
Apparatus as described by claim 1, wherein the means for combining the command signal and the tracer signal includes: means for adding the command signal and the tracer signal.
Claim 6
Dependent Claim
26 words
Apparatus as described by claim 2, wherein: the amplitude of the combined signal is twice said comparator threshold in one polarity and in the opposite polarity.
Claim 7
Dependent Claim
24 words
Apparatus as described by claim 1, wherein: the toggle outputs provided by the comparator means in each of the channels are of different frequencies.
Claim 8
Dependent Claim
48 words
Apparatus as described by claim 3, wherein: the tracer signals generated by each of the channels are alternating signals, each of which has a different frequency; and each of the combined signals has a frequency corresponding to the frequency of the tracer signal with which it is combined.
Claim 9
Dependent Claim
31 words
Apparatus as described by claim 1 wherein: the comparator output toggling between the "good" and the "fail" states insures that the monitoring apparatus does not continuously fail to a "good" state.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |