Smart temperature sensing device

• US 5,857,777 A
• Filed: 09/25/1996
• Issued: 01/12/1999
• Est. Priority Date: 09/25/1996
• Status: Expired due to Term

• Current Assignee: Watlow Electric Manufacturing Company
• Original Assignee: Claud S. Gordon Company
• Inventors: Schuh, William C.
• Primary Examiner(s): Bennett, G. Bradley
• Application Number:
  US08/718,921
• Time in Patent Office: 839 Days
• Field of Search: 374/1, 374/158, 374/163, 374/171, 374/172, 374/173, 374/175, 374/179, 374/183, 374/208, 364/557, 364/558
• US Class Current: 374/172
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers

Abstract

A smart temperature sensing device 10 includes a sensor 16 and a memory 25 on a sensor unit 14. The memory contains a plurality of custom nonlinear calibration coefficients which uniquely characterize the sensor 16. A temperature system includes the smart temperature sensing device 10 and a FSAU 12 having a processor 28 which downloads the calibration coefficients and utilizes them in converting electrical signals from the sensor 16 into temperature values that represent the temperature at the sensor 16. A method of calibrating a sensor 16 includes measuring an output signal of the sensor 16 over a temperature range, thereby obtaining a plurality of paired data points. The paired data points are used in a curve-fitting algorithm to obtain coefficients to a polynomial that characterizes the nonlinear temperature-voltage relationship of the sensor 16. The coefficients are stored within the memory 25 until downloaded by the processor 28 for use in signal conversion.

Claims

1. A temperature sensing device, comprising:

a sensor unit including a sensor operable to sense a temperature; and

a memory integral to the sensor unit, wherein the memory contains nonlinear calibration data which characterize the sensor and wherein the nonlinear calibration data is independent of conversion circuitry which utilizes the nonlinear calibration data in converting a signal representative of the sensed temperature into an output indicative of the temperature.

2. The temperature sensing device of claim 1, wherein the nonlinear calibration data comprises historical data that reflects nonlinear behavior of a particular class of sensors.

3. The temperature sensing device of claim 1, wherein the nonlinear calibration data comprises custom data which uniquely characterizes the sensor.

4. The temperature sensing device of claim 1, wherein the nonlinear calibration data comprises a plurality of nonlinear calibration coefficients.

5. The temperature sensing device of claim 1, further comprising a connector for coupling a processor to the sensor and the memory, wherein the processor is operable to access the nonlinear calibration data from the memory and receive an electrical signal from the sensor which is indicative of the temperature at the sensor, and to convert the electrical signal using the nonlinear calibration data into a temperature value which represents the temperature at the sensor.

6. The sensing device of claim 5, further comprising a noise suppression circuit coupled between the sensor and the processor, wherein the noise suppression circuit eliminates noise, thereby providing a filtered signal to the processor, and wherein the filtered signal is indicative of the temperature at the sensor.

7. The sensing device of claim 5, further comprising an analog-to-digital converter coupled between the sensor and the processor, wherein the analog-to-digital converter is operable to convert the electrical signal from the sensor into a digital signal to be utilized by the processor.

8. The sensing device of claim 5, further comprising a display coupled to the processor for displaying the temperature value which represents the temperature at the sensor.

9. The sensing device of claim 1, wherein the sensor comprises a resistance temperature device.

10. The sensing device of claim 1, wherein the sensor comprises a thermocouple device.

11. The sensing device of claim 1, wherein the memory comprises an electrically erasable programmable read-only memory.

12. A smart temperature sensor system, comprising:

a sensor on a sensor unit, operable to sense a temperature;

a memory on the sensor unit, wherein the memory contains nonlinear calibration data which characterizes the sensor and wherein the nonlinear calibration data is independent of a processor; and

the processor remote from the sensor unit and electrical communication with the sensor and the memory, wherein the processor receives the nonlinear calibration data from the memory and an electrical signal from the sensor, and wherein the processor utilizes the nonlinear calibration data to convert the electrical signal into a value that represents the temperature at the sensor.

13. The smart temperature sensor system of claim 12, wherein the nonlinear calibration data comprises historical data that reflects nonlinear behavior of a particular class of sensors.

14. The smart temperature sensor system of claim 12, wherein the nonlinear calibration data comprises custom data which uniquely characterizes the sensor.

15. The smart temperature sensor system of claim 12, wherein the nonlinear calibration data comprises a plurality of nonlinear calibration coefficients.

16. The smart temperature sensor system of claim 12, wherein the processor communicates with the sensor and the memory through a wired connection.

17. The smart temperature sensor system of claim 12, wherein the processor communicates with the sensor and the memory through an RF connection.

18. The smart temperature sensor system of claim 12, wherein the processor communicates with the sensor and the memory through an IR connection.

19. The smart temperature sensor system of claim 12, further comprising a noise suppression circuit coupled between the sensor and the processor, wherein the noise suppression circuit eliminates noise, thereby providing a filtered signal to the processor which is indicative of the temperature at the sensor.

20. The smart thermal sensor system of claim 12, further comprising an analog-to-digital converter coupled between the sensor and the processor, wherein the analog-to-digital converter is operable to convert the electrical signal from the sensor into a digital signal to be subsequently received by the processor.

21. The smart thermal sensing system of claim 12, further comprising a display coupled to the processor for displaying a temperature value which represents the temperature at the sensor.