Pressure and temperature compensation algorithm for use with a piezo-resistive strain gauge type pressure sensor

1. A method of determining a temperature and a pressure in a tank, the method comprising the steps of:

obtaining sensor data;

calculating coefficients;

ratiometrically determining a bridge resistance from a bridge voltage;

calculating the temperature with selected ones of the coefficients and the bridge resistance;

transitioning from a temperature measurement mode to a pressure measurement mode;

calculating a voltage per resistance with selected ones of the coefficients and a differential voltage;

indirectly compensating for temperature by calculating a normalized voltage using the voltage per resistance, the differential voltage, and the bridge resistance;

calculating the pressure with selected ones of the coefficients and the normalized voltage, the pressure representing a parameter of a product in the tank; and

relaying the temperature to one of a user and a data center.

2. The method of claim 1 , wherein the method further comprises the step of storing the coefficients.

3. The method of claim 1 , wherein the step of calculating coefficients is performed by using the sensor data and a polynomial temperature equation.

4. The method of claim 3 , wherein the step of calculating coefficients is performed by using a voltage per resistance equation and a pressure equation.

5. The method of claim 1 , wherein the step of calculating coefficients is performed by using the sensor data and a second order polynomial temperature equation.

6. A method of determining a temperature and a pressure in a tank, the method comprising the steps of:

obtaining sensor data;

calculating coefficients;

ratiometrically determining a bridge resistance from a bridge voltage;

calculating the temperature with selected ones of the coefficients and the bridge resistance;

transitioning from a temperature measurement mode to a pressure measurement mode;

calculating a voltage per resistance with selected ones of the coefficients and a differential voltage;

indirectly compensating for temperature by calculating a normalized voltage using the voltage per resistance, the differential voltage, and the bridge resistance;

calculating the pressure with selected ones of the coefficients and the normalized voltage, the pressure representing a parameter of a product in the tank; and

relaying the pressure to one of a user and a data center.

7. A method of determining a temperature and a pressure in a tank, the method comprising the steps of:

obtaining sensor data;

calculating coefficients;

ratiometrically determining a bridge resistance from a bridge voltage;

calculating the temperature with selected ones of the coefficients and the bridge resistance;

transitioning from a temperature measurement mode to a pressure measurement mode;

calculating a voltage per resistance with selected ones of the coefficients and a differential voltage;

indirectly compensating for temperature by calculating a normalized voltage using the voltage per resistance, the differential voltage, and the bridge resistance; and

calculating the pressure with selected ones of the coefficients and the normalized voltage, the pressure representing a parameter of a product in the tank; and

wherein the sensor data comprises one or more of a first temperature, a first pressure, a second temperature, a second pressure, a third temperature, a third pressure, first, second, and third voltages, and first, second, and third pressures.

8. A method of determining a temperature compensated pressure in a tank, the method comprising the steps of:

obtaining sensor data;

calculating first coefficients for a voltage per resistance equation with the sensor data;

calculating second coefficients for a pressure equation with the sensor data;

measuring a differential voltage;

calculating a voltage per resistance with the voltage per resistance equation using the first coefficients and the differential voltage;

calculating a normalized voltage with a normalized voltage equation using the voltage per resistance, the differential voltage, and the bridge resistance; and

calculating the temperature compensated pressure with the second coefficients and the normalized voltage, the temperature compensated pressure representing a level of a product in the tank.

9. The method of claim 8 , further comprising the step of calculating a temperature in a tank comprising the steps of:

calculating third coefficients for a temperature equation with the sensor data;

measuring a bridge voltage;

ratiometrically determining a bridge resistance with the bridge voltage;

calculating a temperature with the temperature equation using the third coefficients and the bridge resistance.

10. The method of claim 9 , wherein the method further comprises the step of relaying at least one of the temperature and the pressure to a user.

11. The method of claim 9 , wherein the third coefficients consists of three coefficients.

12. The method of claim 9 , wherein the method further comprises employing an additional second order temperature polynomial to compensate for errors.

13. The method of claim 9 , wherein the method further comprises the step of storing at least one of the first, second, and third coefficients.

14. The method of claim 8 , wherein the method further comprises the step of reporting the pressure to at least one of a user and a data center.

15. The method of claim 8 , wherein the first coefficients consists of two coefficients and the second coefficients consist of two coefficients.

16. The method of claim 8 , wherein the voltage per resistance equation and the pressure equation are free of a temperature variable.

17. A method of determining a temperature in a tank, the method comprising the steps of:

obtaining sensor data;

calculating first coefficients for a temperature equation with the sensor data;

measuring a bridge voltage;

ratiometrically determining a bridge resistance with the bridge voltage;

calculating a temperature using the first coefficients and the bridge resistance, the temperature providing an indication of the temperature in the tank; and

determining a pressure in a tank comprising the steps of:

calculating second coefficients for a voltage per resistance equation with the sensor data;

calculating third coefficients for a pressure equation with the sensor data;

measuring a differential voltage;

calculating a voltage per resistance with the voltage per resistance equation using the second coefficients and the differential voltage;

indirectly calculating a normalized voltage with a normalized voltage equation using the voltage per resistance, the differential voltage, and the bridge resistance; and

calculating a pressure with the third coefficients and the normalized voltage.

18. A method of determining a temperature in a tank, the method comprising the steps of:

obtaining sensor data;

calculating first coefficients for a temperature equation with the sensor data;

measuring a bridge voltage;

ratiometrically determining a bridge resistance with the bridge voltage;

calculating a temperature using the first coefficients and the bridge resistance, the temperature providing an indication of the temperature in the tank; and

relaying the temperature to one of a user and a data center.