US3772602A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process controller with bumpless transfer
Assignee: Fischer and Porter Co
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Filing: 1972-09-05
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Granted: 1973-11-13
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Expires: 1992-09-05
Abstract
Abstract A process controller operable in the automatic or manual mode without producing a bump as a result of setpoint transfer or automatic-to-manual transfer. The setpoint and manual control stations may be constituted by an operational amplifier and a holding capacitor. Output drift of these stations due to leakage is suppressed effectively by a single drift compensation circuit whose output is applied to these stations selectively or alternately on a time-sharing basis.
Inventors
- 👤 T Kobayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:02
CPC Classifications
G; G11; G11C; G11C27/00; G11C27/02; G11C27/024; G11C27/026; G05; G05B; G05B7/00; G05B7/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
141 words
A process controller operable in an automatic or a manual control mode comprising: A. a manual control station having an integral hold circuit when the controller is in the manual control mode; B. a setpoint station having an integral hold circuit; C. an automatic control station coupled to said setpoint station to compare a process variable with a setpoint valve provided by the setpoint station to produce a control integral for performing control functions; D. a drift compensation circuit adapted to convert the output of an integral hold circuit to digital signals and to deliver to the input of said integral hold circuit a compensation signal related to the last digit in said digital signals and varying therewith, and E. switching means alternately or selectively to connect said drift compensation circuit to said manual control station and to said setpoint station.
Claim 2
Dependent Claim
141 words
A process controller operable in an automatic or a manual control mode comprising: A. a manual control station having an integral hold circuit when the controller is in the manual control mode; B. a setpoint station having an integral hold circuit; C. an automatic control station coupled to said setpoint station to compare a process variable with a setpoint valve provided by the setpoint station to produce a control integral for performing control functions; D. a drift compensation circuit adapted to convert the output of an integral hold circuit to digital signals and to deliver to the input of said integral hold circuit a compensation signal related to the last digit in said digital signals and varying therewith, and E. switching means alternately or selectively to connect said drift compensation circuit to said manual control station and to said setpoint station.
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) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |