Characterization of process pressure sensor

• US 6,935,156 B2
• Filed: 09/30/2003
• Issued: 08/30/2005
• Est. Priority Date: 09/30/2003
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Incorporated (Emerson Electric Company)
• Inventors: Schumacher, Mark S., Wiklund, David Eugene, Beachey, Terry Xen, Broden, David Andrew, Fogarty, Timothy Patrick
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): BELLAMY, TAMIKO D
• Application Number:
  US10/675,214
• Publication Number:
  US 20050066703A1
• Time in Patent Office: 700 Days
• Field of Search: 73/13.5, 73/15.7, 73/17.1, 73/15.9, 702/45, 702/47, 702/98, 702/100, 702/104, 702/138
• US Class Current: 73/1.57
• CPC Class Codes: G01L 27/005 Apparatus for calibrating pressure sensors

Abstract

A pressure sensor of a process device, is characterized by applying a plurality of pressures to the process sensor. Outputs of the plurality of pressures are received. A compensation relationship is determined based upon the pressure sensor output. The characterization data is collected in a distribution which is non-uniform across the pressure range.

Claims

1. A method of characterizing a pressure sensor of a process device, comprising:

applying a plurality of pressures to a pressure sensor of the process device across a characterization pressure range; and

receiving outputs from the pressure sensor related to the applied pressure;

determining a compensation relationship based upon the outputs from the pressure sensor;

wherein different applied pressures are non-uniformly distributed across the characterization pressure range.

2. The method of claim 1 wherein the process device comprises a flow transmitter.

3. The method of claim 1 wherein the process device comprises a level transmitter.

4. The method of claim 1 wherein the compensation relationship comprises a polynomial.

5. The method of claim 1 including comparing outputs of the pressure sensor at the plurality of differential pressures with reference values.

6. The method of claim 1 wherein the distribution of applied pressures is a linear function.

7. The method of claim 1 wherein the distribution of applied pressures is an exponential function.

8. The method of claim 1 wherein the distribution of applied pressures is a logarithmic function.

9. The method of claim 1 wherein the step of applying includes applying pressures at closer intervals over a lower pressure range than over a higher pressure range.

10. The method of claim 1 wherein the step of applying a plurality of pressures is performed at more than one temperature.

11. The method of claim 1 wherein the step of applying a plurality of pressures comprises moving a fluid past a primary element to create a differential pressure.

12. The method of claim 1 including storing compensation values in a memory of the process device which are related to the compensation relationship.

13. The method of claim 1 wherein the compensation values comprise polynomial coefficients.

14. The method of claim 1 wherein the pressure sensor comprises a differential pressure sensor.

15. The method of claim 1 wherein the characterization is for differential pressure and static pressure.

16. The method of claim 1 wherein the characterization is for static pressure and temperature.

17. A calibration apparatus configured to couple to the process device and implement the method of claim 1.

18. A process device including compensation values stored in a memory which are determined in accordance with the method of claim 1.