Digitally-temperature-compensated strain-gauge pressure measuring apparatus
US5460049A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 26, 1994 |
| Grant date | Oct 24, 1995 |
| Priority date | — |
| Expiry date | Jan 26, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L9/065
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A strain gauge exhibits temperature offset errors and span errors which vary from device to device and vary as a function of temperature. A digitally-compensated strain-gauge apparatus executes embedded calibration and compensation programs for improving accuracy over a wide temperature range. Pressure measurement error bands are reduced to approximately to 0.03% of full scale for a 5 psi device over a 0.degree. C. to 50.degree. C. temperature range. A calibration program defines parameters for compensating for such errors. During field operation, a compensation program uses the calibration parameters to generate a more accurate pressure measurement. According to the compensation scheme, current normalized voltage and bridge impedance are derived from the raw data. A first-pass temperature estimate then is derived from the result. The derived first-pass temperature estimate is plugged into a temperature offset error function to find the temperature offset error at the estimated temperature. Such offset error is used to adjust the current normalized voltage. A first-pass pressure estimate is derived from the adjusted current-normalized voltage, then used to correct the bridge impeda…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.