Highly accurate platform weighing system
US4836308A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 4, 1988 |
| Grant date | Jun 6, 1989 |
| Priority date | — |
| Expiry date | Apr 4, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01G23/01
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A platform weighing system (10) suitable for making accurate weight measurements of heavy objects, such as aircraft, is disclosed. Hardware and software combine to produce the accurate results. Analog hardware (14) includes hydraulic load cells (80a-80d), temperature sensing (91), filtering (90), and voltage-to-frequency conversion (104). Digital hardware (12) receives an oscillation signal output from the voltage-to-frequency conversion (104) and obtains load counts by monitoring the oscillation signal for consistent predetermined durations. The predetermined duration is chosen in software (226) to be immune to particularly pervasive noise signals. A microprocessor (16) converts load counts into a weight code which is output to a display (46). This conversion includes compensation for auto ranging (320), load cell excitation variance (282), temperature compensation (284), null offset variance (286), and zero drifting (304). In addition, nonlinearities in load cell output are compensated by linearly interpolating (288-296) between two of a plurality of calibration points that characterize the load cells (80a-80d ). Such compensations are performed primarily in software (200).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.