US3843914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital speed control system
Assignee: Detection Sciences Inc
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Filing: 1972-10-30
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Granted: 1974-10-22
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Expires: 1992-10-30
Abstract
Abstract A digital motor speed control system employing a phase locked loop for generating a frequency proportional to the desired motor speed, which frequency is variable over a wide range in response to operator settable digital switches. A signal comparison circuit provides control signals to the motor in response to the relationship between the frequency of the signals from the phase locked loop and the frequency of feedback signals from a speed sensor associated with the motor. The relationship between the frequencies of these two signals which is sensed by a signal comparison circuit, is itself a variable function determined by the programming of the comparison circuit. The comparison circuit is easily programmable for any given application of the speed controller so that the number set in the switches reads directly in terms of units of measure appropriate to the process to be driven by the motor.
Inventors
- 👤 R Carlson
- 👤 R Barr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:58
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/18; H02P23/186; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/909; Y10S388/911; Y10S388/912
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
226 words
A programmable digital speed control system for controlling the speed of a motor, comprising: a. adjustable means for receiving a speed command number and for providing speed command signals in response thereto having a frequency indicative of a desired motor speed; b. means associated with said motor for providing speed pulses, the period between pulses being inversely proportional to the speed of the motor; c. programmed counter means connected to receive said speed command signals and said speed pulses, said programmed counter means operable in a first state initiated by receipt of a speed pulse to count said speed command signals, and operable in a second state initiated by reaching a predetermined count to cease counting until receipt of the next speed pulse; and d. a motor control circuit including integrating means connected to said programmed counter for integrating in one direction tending to decelerate the motor when said programmed counter is in said first state, and for integrating in the opposite direction tending to accelerate the motor when said programmed counter is in said second state, whereby the speed of the motor is caused to be adjusted so that the period of time between the reaching of the predetermined count and the next speed pulse is made to equal the period of time required for the programmed counter to count the predetermined number of pulses.
Claim 2
Dependent Claim
226 words
A programmable digital speed control system for controlling the speed of a motor, comprising: a. adjustable means for receiving a speed command number and for providing speed command signals in response thereto having a frequency indicative of a desired motor speed; b. means associated with said motor for providing speed pulses, the period between pulses being inversely proportional to the speed of the motor; c. programmed counter means connected to receive said speed command signals and said speed pulses, said programmed counter means operable in a first state initiated by receipt of a speed pulse to count said speed command signals, and operable in a second state initiated by reaching a predetermined count to cease counting until receipt of the next speed pulse; and d. a motor control circuit including integrating means connected to said programmed counter for integrating in one direction tending to decelerate the motor when said programmed counter is in said first state, and for integrating in the opposite direction tending to accelerate the motor when said programmed counter is in said second state, whereby the speed of the motor is caused to be adjusted so that the period of time between the reaching of the predetermined count and the next speed pulse is made to equal the period of time required for the programmed counter to count the predetermined number of pulses.
Claim 3
Dependent Claim
115 words
Apparatus according to claim 1, wherein said programmed counter means comprises: a. a counter; b. a gate connected for selectively applying said speed command signals to said counter; c. means for resetting said counter in response to a speed pUlse; and d. a detector connected to said gate and connected to said counter according to a predetermined program number, said detector operable when the count in said counter is less than the program number to enable said gate to permit said counter to count speed command impulses, said detector further operable when the count in said counter reaches said program number to inhibit said gate, until the counter is reset by the next speed pulse.
Claim 4
Dependent Claim
17 words
Apparatus according to claim 2, wherein said integrating means is connected to the output of said detector.
Claim 5
Dependent Claim
37 words
Apparatus according to claim 2, wherein said counter includes a plurality of binary stages, and wherein said detector has a plurality of inputs which are selectively connectable to stages of said counter according to said program number.
Claim 6
Dependent Claim
12 words
Apparatus according to claim 4, wherein said detector comprises a NOR gate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |