US3778696A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Feedback fault indicate circuit
Assignee: Allen Bradley Co LLC
•
Filing: 1972-06-23
•
Granted: 1973-12-11
•
Expires: 1992-06-23
Abstract
Abstract In the servo system of a numerically controlled machine the position feedback signal is monitored by a fault indicate circuit. An absolute analog position signal is generated by an integrator circuit connected to receive a signal proportional to machine speed. Under normal operating conditions, the integrator circuit is repeatedly reset to zero by a reference reset switch and the magnitude of the absolute position signal is thus maintained below a preset limit. The reference reset switch is controlled by the position feedback signal being monitored and when the feedback signal is lost due to a malfunction, the integrator circuit is not reset and the absolute analog position signal rises above the preset limit. This condition is sensed by a level detector which generates a fault indicate signal.
Inventors
- 👤 R Walters
- 👤 T Markley
- 👤 R Jennings
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 20:38
CPC Classifications
G; G05; G05B; G05B19/00; G05B19/02; G05B19/18; G05B19/19; G05B19/21; G05B2219/00; G05B2219/30; G05B2219/42; G05B2219/42308
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
115 words
A fault indicate circuit for monitoring a position feedback signal generated by a position transducer, the combination comprising: an analog signal generator connected to sense machine motion and generate an analog position signal; a reference reset switch connected to receive the position feedback signal and connected to said analog signal generator to reset the same to zero when actuated by said position feedback signal; and a level detector connected to receive the analog position signal and generate a fault indicate signal when the magnitude thereof exceeds a preset limit, wherein the reference reset switch is responsive to the position feedback signal to maintain said analog position signal below said preset limit during normal operating conditions.
Claim 2
Dependent Claim
115 words
A fault indicate circuit for monitoring a position feedback signal generated by a position transducer, the combination comprising: an analog signal generator connected to sense machine motion and generate an analog position signal; a reference reset switch connected to receive the position feedback signal and connected to said analog signal generator to reset the same to zero when actuated by said position feedback signal; and a level detector connected to receive the analog position signal and generate a fault indicate signal when the magnitude thereof exceeds a preset limit, wherein the reference reset switch is responsive to the position feedback signal to maintain said analog position signal below said preset limit during normal operating conditions.
Claim 3
Dependent Claim
34 words
The fault indicate circuit of claim 1 in which said analog signal generator includes an integrator circuit having an input connected to receive a speed signal and an output connected to said level detector.
Claim 4
Dependent Claim
40 words
The fault indicate circuit of claim 2 in which said integrator circuit includes a feedback capacitor, the reference reset switch is connected across said feedback capacitor, and the analog signal generator is reset to zero by discharging the feedback capacitor.
Claim 5
Dependent Claim
39 words
The Fault indicate circuit of claim 2 in which said analog signal generator includes an absolute value circuit connected to receive a signal proportional to machine speed and generate a speed signal of singular polarity to said integrator circuit.
Claim 6
Dependent Claim
48 words
The fault indicate circuit of claim 4 in which the integrator circuit includes an operational amplifier having a feedback capacitor connected between an input terminal and an output terminal thereof, and said reference reset switch includes a transistor having its current carrying elements connected across said feedback capacitor.
Claim 7
Dependent Claim
142 words
A fault indicate circuit connected to receive a position feedback signal generated by the position transducer on a numerically controlled machine, the combination comprising: a digital feedback generator connected to receive the position feedback signal and adapted to generate digital feedback pulses at a rate proportional to the rate of displacement indicated by the position feedback signal; an analog signal generator connected to sense machine motion and generate an analog position signal, the amplitude of which changes in proportion to the amount of machine displacement; a reference reset switch connected for actuation by the digital feedback pulses and connected to said analog signal generator to reset it to zero each time the reference reset switch is actuated; and a level detector connected to receive the analog position signal and generate a fault indicate signal when the amplitude thereof exceeds a preset level.
Claim 8
Dependent Claim
142 words
A fault indicate circuit connected to receive a position feedback signal generated by the position transducer on a numerically controlled machine, the combination comprising: a digital feedback generator connected to receive the position feedback signal and adapted to generate digital feedback pulses at a rate proportional to the rate of displacement indicated by the position feedback signal; an analog signal generator connected to sense machine motion and generate an analog position signal, the amplitude of which changes in proportion to the amount of machine displacement; a reference reset switch connected for actuation by the digital feedback pulses and connected to said analog signal generator to reset it to zero each time the reference reset switch is actuated; and a level detector connected to receive the analog position signal and generate a fault indicate signal when the amplitude thereof exceeds a preset level.
Claim 9
Dependent Claim
96 words
The fault indicate circuit of claim 6 wherein the position transducer is a shaft encoder that generates a plurality of digital incremental position feedback signals and said digital feedback generator includes: A flip-flop connected to receive said digital incremental position feedback signals; and a monoshot circuit having an input connected to said flip-flop and an output connected to the reference reset switch, wherein the monoshot circuit generates a digital feedback pulse to the reference reset switch each time the flip-flop is cycled through its set and reset state by the received digital incremental position feedback signals.
Claim 10
Dependent Claim
37 words
The fault indicate circuit as recited in claim 7 in which said digital feedback generator includes an idle pulse generator connected to operate said reference reset switch at a low repetition rate when the machine is idling.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |