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US 5,345,042 AGranted
Elevator hitch load weighing tare compensation
AssigneeOtis Elevator Company
InventorEric K. Jamieson
Life of this patent
Estimating the term…
Abstract
In an elevator hitch load weighing assembly, a load cell provides an analog load signal to a summer 12, where an analog tare compensation signal is subtracted from the load signal prior to a compensated load signal being provided to an analog-to-digital converter (ADC) 20; the digital load signal is provided to a remaining tare subtractor 26 where tare remaining in the digital load signal is subtracted and a payload provided.
Claims9
A method of moving an elevator car, comprising the steps:
- a) providing an analog load signal indicative of weight on a car hitch;
- b) providing an analog tare compensation signal;
- c) providing a compensated analog load signal in response to a difference between said analog tare compensation signal and said analog load signal;
- d) converting said compensated analog load signal into a digital load signal;
- e) providing a digital stored load signal in response to said digital load signal;
- f) providing a payload signal in response to a difference between said digital stored load signal and said digital load signal;
- and
- g) moving an elevator car in response to said payload signal.
5 more elements
A method of compensation tare in an elevator load weight signal, comprising the steps of:
- providing an analog load signal indicative of weight on a car hitch;
- providing an analog tare compensation signal wherein said step of providing an analog tare compensation signal includes:
- measuring a static tare;
- providing a slope describing a relationship between elevator position and tare;
- multiplying said slope by said static tare for providing a product;
- and
- summing said product with said elevator position for providing said analog tare compensation signal;
- and
- providing a compensated analog load signal in response to a difference between said analog tare compensation signal and said analog load signal.
6 more elements
A method of compensating tare in an elevator load weight signal, comprising the steps of:
- providing an analog load signal indicative of weight on a car hitch;
- providing an analog tare compensation signal including:
- measuring a static tare;
- obtaining a slope describing a linear relationship between elevator position and tare including:
- moving an empty car to a first floor of a hoistway;
- measuring said digital load signal;
- comparing said digital load signal with an estimated remaining tare and adjusting a magnitude of a digital tare compensation signal until a magnitude of said digital load signal is less than said estimated remaining tare;
- measuring and storing a first floor digital tare compensation signal;
- moving said empty elevator to a second floor in said hoistway;
- measuring said digital load signal while said car is at a top of said hoistway;
- comparing said digital load signal with an estimated remaining tare and adjusting the magnitude of a digital tare compensation signal until the magnitude of said digital load signal is less than said estimated remaining tare while the car is at the top of said hoistway;
- measuring and storing a second floor digital tare compensation signal;
- and
- dividing a hoistway length by a difference between said first floor digital tare compensation signal and said second floor digital tare compensation signal ;
- multiplying said slope by said elevator position for obtaining a product;
- summing said product with said elevator position for providing said analog tare compensation signal;
- and
- providing a compensated analog load signal in response to a difference between said analog tare compensation signal and said analog load signal.
15 more elements
A method of compensating tare in an elevator load weight signal, comprising the steps of:
- providing an analog load signal indicative of weight on a car hitch;
- providing an analog tare compensation signal;
- and
- providing a compensated analog load signal in response to a difference between said analog tare compensation signal and said analog load signal;
- converting said compensated analog load signal into a digital load signal;
- providing a digital stored load signal including:
- moving said empty elevator from one end of said hoistway to another in response to said analog tare compensation signal;
- and
- measuring a magnitude of said digital load signal at each floor in said hoistway and storing said digital load signal in a remaining tare table and providing a digital stored load signal whose value comes from the remaining tare table;
- providing a payload signal in response to a difference between said digital stored load signal from said digital load signal.
7 more elements
An elevator load weighing apparatus, comprising:
- a summer, responsive to an analog load signal indicative of weight on a car hitch and an analog tare compensation signal, which provides a compensated load signal;
- an analog-to-digital converter, responsive to said compensated load signal, which provides a digital load signal;
- a tare compensator, responsive to said digital load signal and an elevator position signal, which provides a digital tare compensation signal;
- and
- a digital-to-analog converter, responsive to said digital tare compensation signal, which provides an analog tare compensation signal.
2 more elements
Dependencies are inferred from the claim text.