Application specific integrated circuitry for controlling analysis of a fluid

• US 20040107055A1
• Filed: 03/21/2003
• Published: 06/03/2004
• Est. Priority Date: 10/18/2002
• Status: Active Grant

• Current Assignee: Meas France
• Original Assignee: Symyx Technologies Incorporated (Dassault Systemes SA)
• Inventors: Matsiev, Leonid, Gammer, Vladimir, Kolosov, Oleg V., Spitkovsky, Mikhail B.
• Granted Patent: US 6,873,916 B2
• Time in Patent Office: Days
• US Class Current: 702/25
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/34 Generating the ultrasonic, sonic or infrasonic waves , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01N 29/36 Detecting the response signal , e.g. electronic circuits specially adapted therefor

Abstract

A circuit for determining characteristics of a fluid under-test is provided. The circuit includes analog-to-digital processing circuitry for interfacing with a sensor and host electronics. The analog-to-digital processing circuitry includes a frequency generator for providing stimulus to the sensor and receiving a response signal from the sensor. Conditioning circuitry for reducing analog signal offsets in the response signal and signal detection circuitry for identifying amplitude data of the response signal are provided. Further provided is analog-to-digital conversion circuitry for converting the detected amplitude data into digital form. Memory for holding calibration data and approximated fluid characteristics of the fluid under-test is included in the circuitry. The digital form of the response signal is processed in conjunction with the calibration data and approximated fluid characteristics to generate fluid characteristics of the actual fluid under-test.

Claims

1. A system for sensing characteristics of a fluid, comprising:

a tuning fork configured to be at least partially submerged in a fluid under-test; and

an application specific integrated circuit (ASIC), the ASIC including, analog input/output circuitry for providing stimulus to the tuning fork and receiving a response signal from the tuning fork;

conditioning circuitry for reducing analog signal offsets in the response signal;

signal detection circuitry for identifying amplitude data of the response signal;

analog-to-digital conversion circuitry for converting the detected amplitude data into digital form; and

memory for holding user defined data, wherein the digital form of the response signal is processed in conjunction with the user defined data to generate fluid characteristics of the fluid under-test.

2. A system for sensing characteristics of a fluid as recited in claim 1, wherein the user defined data includes at least one of calibration data and approximated fluid characteristics of the fluid under-test.

3. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC is in communication with a processor, the processor being configured to process a fitting algorithm to ascertain the fluid characteristics of the fluid under-test.

4. A system for sensing characteristics of a fluid as recited in claim 3, wherein the ASIC further includes an integrated CPU, the CPU being configured to process a fitting algorithm to ascertain the fluid characteristics of the fluid under-test 5. A system for sensing characteristics of a fluid as recited in claim 3, wherein the fitting algorithm implements a simplex equation to minimize least squares values.

6. A system for sensing characteristics of a fluid as recited in claim 4, wherein the fitting algorithm implements a simplex equation to minimize least squares values.

7. A system for sensing characteristics of a fluid as recited in claim 2, further comprising:

a temperature sensor, the temperature sensor designed to read a temperature next to the tuning fork, the temperature reading being utilized to select a temperature specific set of calibration data and approximated fluid characteristics of the fluid under-test.

8. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC is coupled to local machine electronics of a machine.

9. A system for sensing characteristics of a fluid as recited in claim 8, wherein the machine is an automobile and the fluid under-test is engine oil.

10. A system for sensing characteristics of a fluid as recited in claim 9, further comprising:

a local machine user interface for providing one of analog and digital data regarding the fluid characteristics of the fluid under-test.

11. A system for sensing characteristics of a fluid as recited in claim 8, wherein the local machine electronics includes engine control electronics.

12. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC includes digital logic control for interfacing components internal to the ASIC to components external to the ASIC.

13. A system for sensing characteristics of a fluid as recited in claim 12, wherein the ASIC is integrated into electronics of one of a motor, a measurement while drilling tool, a logging while drilling tool, an exploration and production well logging tool, a printed circuit board, and a computer motherboard.

14. A system for sensing characteristics of a fluid as recited in claim 1, wherein the generated generate fluid characteristics of the fluid under-test are displayed on a display monitor.

15. A system for sensing characteristics of a fluid as recited in claim 1, wherein the memory is rewritable.

16. A system for sensing characteristics of a fluid as recited in claim 2, wherein one or both of the calibration data and approximated fluid characteristics of the fluid under-test are capable of being stored on one of a memory card, a memory stick, a hard drive, an optical disc, and on a network storage.

17. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC further comprises:

glue logic for interfacing components of the ASIC.

18. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC further comprises:

a digital 110 for interfacing with a computer.

19. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC further comprises:

a ROM;

a RAM;

a CPU; and

a clock.

20. A system for sensing characteristics of a fluid as recited in claim 1, wherein the ASIC further comprises:

a timer.

21. A system for sensing characteristics of a fluid as recited in claim 1, wherein the tuning fork has an integrated capacitor.

22. A system for sensing characteristics of a fluid as recited in claim 1, wherein the signal conditioning circuitry includes,

a differential amplifier for receiving an input from tuning fork, the input from the tuning fork being the response signal;

and

a capacitor coupled to an input of the differential amplifier.

23. A system for sensing characteristics of a fluid as recited in claim 21, wherein the capacitor is integrated on the tuning fork.

24. A system for sensing characteristics of a fluid as recited in claim 1, wherein the signal conditioning circuitry includes,

a differential amplifier for receiving an input from tuning fork, the input from the tuning fork being the response signal;

and

a digital-to-analog converter for providing compensation to one of the signal detection circuitry and the analog-to-digital converter.

25. A system for sensing characteristics of a fluid as recited in claim 23, further including,

a capacitor coupled to an input of the differential amplifier.

26. A system for sensing characteristics of a fluid as recited in claim 1, wherein the signal conditioning circuitry includes,

a differential amplifier for receiving an input from tuning fork, the input from the tuning fork being the response signal;

a capacitor coupled to an input of the differential amplifier; and

a summation amplifier, the summation amplifier coupled between the differential amplifier and the capacitor.

27. A circuit for determining characteristics of a fluid under-test, comprising:

analog-to-digital processing circuitry for interfacing with a sensor and host electronics, the analog-to-digital processing circuitry including, a frequency generator for providing stimulus to the sensor;

conditioning circuitry for receiving a response signal from the sensor and reducing analog signal offsets in the response signal;

signal detection circuitry for identifying amplitude data of the response signal;

analog-to-digital conversion circuitry for converting the detected amplitude data into digital form; and

memory capable of holding data characterizing the sensor, wherein the digital form of the response signal is processed to generate fluid characteristics of the fluid under-test.

28. A circuit for determining characteristics of a fluid under-test as recited in claim 27, wherein the data characterizing the sensor includes calibration data.

29. A circuit for determining characteristics of a fluid under-test as recited in claim 27, wherein the memory further being capable of holding approximated characteristic data of the fluid under-test.

30. A system for determining characteristics of a fluid as recited in claim 27, wherein the analog-to-digital processing circuitry is incorporated into an application specific integrated circuit (ASIC).

31. A system for determining characteristics of a fluid as recited in claim 27, wherein the signal conditioning circuitry and the memory are integrated into an application specific integrated circuit (ASIC).

32. A system for determining characteristics of a fluid as recited in claim 27, wherein the signal conditioning circuitry, the signal detection circuitry, and the memory are integrated into an application specific integrated circuit (ASIC).

33. A system for determining characteristics of a fluid as recited in claim 27, wherein the signal conditioning circuitry, the signal detection circuitry, the frequency generator, and the memory are integrated into an application specific integrated circuit (ASIC).

34. A system for determining characteristics of a fluid as recited in claim 27, wherein the signal conditioning circuitry, the signal detection circuitry, the frequency generator, the analog-to-digital conversion circuitry and the memory are integrated into an application specific integrated circuit (ASIC).

35. A system for determining characteristics of a fluid as recited in claim 34, wherein the ASIC further includes an integrated processor.

36. A system for determining characteristics of a fluid as recited in claim 35, wherein the integrated processor is one of a CPU, a microprocessor core, a microcontroller, a state machine, a digital signal processor.

37. A system for determining characteristics of a fluid as recited in claim 27, wherein the signal detection circuitry includes one of an RMS detector and a synchronous detector.

38. A system for determining characteristics of a fluid as recited in claim 27, wherein the sensor is a mechanical resonator.

39. A system for determining characteristics of a fluid as recited in claim 36, wherein the mechanical resonator is a tuning fork.

40. A system for determining characteristics of a fluid as recited in claim 27, wherein the sensor is a tuning fork with an integrated capacitor.

41. A system for determining characteristics of a fluid as recited in claim 28, wherein the ASIC is integrated with the sensor.

42. A system for determining characteristics of a fluid as recited in claim 28, wherein the ASIC is integrated in vehicle electronics.

43. A system for determining characteristics of a fluid as recited in claim 28, wherein the fluid under-test is vehicle fluid.

44. A system for determining characteristics of a fluid as recited in claim 28, wherein the vehicle fluid is oil.

45. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test, the mechanical sensor being at least partially submerged in the fluid under-test, the method comprising:

applying a variable frequency signal to the sensor;

receiving a frequency response from the sensor;

conditioning the frequency response;

detecting signal components of the frequency response;

converting the frequency response to digital form, the digital form being representative of the frequency response received from the sensor;

fetching first calibration variables from memory, the first calibration variables defining physical characteristics of the sensor;

fetching second calibration variables from memory, the second calibration variables defining characteristics of the sensor in a known fluid; and

processing the digital form of the response received from the sensor when in the fluid under-test along with the fetched first and second calibration variables, the processing implementing a fitting algorithm to produce fluid characteristics of the fluid under-test.

46. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein the fluid characteristics produced for the fluid under-test include density, viscosity and dielectric constant values.

47. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein the fitting algorithm executes a simplex equation to minimize least squares.

48. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein the first calibration of the sensor is performed in one of air and vacuum.

49. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein known fluid is a volatile fluid.

50. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein the first calibration and the second calibration utilize the fitting algorithm.

51. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein the method operations are executed using circuitry.

52. A method for interfacing with a mechanical sensor to obtain characteristics of a fluid under-test as recited in claim 45, wherein some of the circuitry is part of an application specific integrated circuit (ASIC).

53. A method for interfacing with a tuning fork to obtain characteristics of a fluid under-test, the tuning fork being at least partially submerged in the fluid under-test, the method comprising:

applying a variable frequency signal to the tuning fork;

receiving a frequency response from the tuning fork;

conditioning the frequency response;

detecting at least one signal component of the frequency response;

converting the frequency response to digital form, the digital form being representative of the frequency response received from the tuning fork;

fetching calibration variables for the tuning fork; and

processing the digital form of the response received from the tuning fork when in the fluid under-test along with the fetched calibration variables, the processing implementing a fitting algorithm to produce fluid characteristics of the fluid under-test.

55. A method for interfacing with a tuning fork to obtain characteristics of a fluid under-test as recited in claim 53, wherein the variable frequency signal is between about 5 kHz and about 50 kHz.

56. A method for interfacing with a tuning fork to obtain characteristics of a fluid under-test as recited in claim 53, wherein some of the circuitry is part of an application specific integrated circuit (ASIC).

58. An application specific circuit (ASIC) for processing signals used to determine characteristics of a fluid under-test as recited in claim 56, wherein the ASIC is integrated into a semiconductor chip.

54. A method for interfacing with a tuning fork to obtain characteristics of a fluid under-test as recited in claim 553, wherein the variable frequency signal is less than 100 kHz.

57. An application specific integrated circuit (ASIC) for processing signals used to determine characteristics of a fluid under-test, the ASIC being in communication with a tuning fork designed to operate a frequency that is less than 100 kHz, comprising:

circuitry for communicating a frequency signal to the tuning fork;

circuitry for processing the a response signal received from the tuning fork into digital form;

circuitry for storing calibration data for the tuning fork;

circuitry for executing a fitting algorithm to ascertain characteristics of the fluid-under-test, the executing utilizing the calibration data; and

circuitry for interfacing the ASIC circuitry that is external to the ASIC.