Embedded data acquisition and control system for non-invasive glucose prediction instrument

• US 6,587,199 B1
• Filed: 02/25/2000
• Issued: 07/01/2003
• Est. Priority Date: 02/25/2000
• Status: Expired due to Fees

• Current Assignee: GLT Acquisition Corporation
• Original Assignee: Sensys Medical, Inc. (Sensys Medical Limited)
• Inventors: Luu, Ui
• Primary Examiner(s): Smith, Zandra V.
• Application Number:
  US09/513,551
• Time in Patent Office: 1,222 Days
• Field of Search: 356/326, 356/328, 356/332, 356/331, 702/30
• US Class Current: 356/332
• CPC Class Codes: G01J 3/06 Scanning arrangements arrangements for order-selection

Abstract

An embedded data acquisition and control system for a precision instruments, such as a non-invasive glucose prediction instrument is disclosed. One feature of the invention provides synchronization of stepper motor position and analog-to-digital converters. An embedded controller is provided that controls the stepper motor driver directly to minimize the wavelength shift error due to the asynchronous condition. The controller synchronizes the event of reading the A/D converters with each stepper motor position. Because the stepper motor controls the wavelength of the monochromator optical output, the net result is that each A/D conversion recorded by the embedded controller is precisely tracked to a specific wavelength. Another feature of the invention provides closed loop motor position control for enhanced system performance. In the closed loop system, a position encoder is coupled to the stepper motor shaft. The encoded position signal is processed by a digital encoder at the bipolar stepper motor drive, resulting in an actual position feedback to the embedded controller. Because the embedded controller has the position feedback, it can initiate the next step command as soon as the position feedback reaches its target. The step rate is increased by reducing the time delay that was set by a conservative value as indicated in the open loop control mode. One advantage of this method is to achieve highest speed in all load conditions without missing steps. A further feature of the invention provides optical Isolation to minimize motor noise. Thus, optical isolation is provided at a bipolar stepper motor drive and embedded controller interface. To maximize system sensitivity, optical isolation is implemented between the embedded controller and the stepper motor drive.

Claims

1. A data acquisition and control system for a precision instrument, comprising:

a monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

an analog-to-digital converter;

an embedded controller for synchronizing said stepper motor position and said analog-to-digital converter; and

optical isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and controller interface.

2. The data acquisition and control system of claim 1, wherein said controller synchronizes reading of said A/D converter with each stepper motor position;

and wherein each A/D conversion recorded by said controller is precisely tracked to a specific wavelength.

3. The data acquisition and control system of claim 1, further comprising:

a closed loop motor position controller.

4. The data acquisition and control system of claim 3, said closed loop motor position controller comprising:

a digital position encoder is coupled to a stepper motor shaft; and

a bipolar stepper motor drive.

5. The data acquisition and control system of claim 4, wherein an encoded position signal is processed by said digital position encoder at said bipolar stepper motor drive to provide actual position feedback to said controller.

6. The data acquisition and control system of claim 5, wherein said controller initiates a next step command as soon as said position feedback reaches its target.

7. A data acquisition and control system for a precision instrument, comprising:

a monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

an analog-to-digital converter;

an embedded closed loop motor position controller; and

optical isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and controller interface.

8. The data acquisition and control system of claim 7, said closed loop motor position controller comprising:

a digital position encoder is coupled to a stepper motor shaft; and

a bipolar stepper motor drive.

9. The data acquisition and control system of claim 8, wherein an encoded position signal is processed by said digital position encoder at said bipolar stepper motor drive to provide actual position feedback to said controller.

10. The data acquisition and control system of claim 9, wherein said controller initiates a next step command as soon as said position feedback reaches its target.

11. A data acquisition and control system for a precision instrument, comprising:

monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

an analog-to-digital converter; and

optical isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and embedded controller interface.

12. A data acquisition and control process for a precision instrument, comprising the steps of:

providing a monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

providing an analog-to-digital converter;

synchronizing said stepper motor position and said analog-to-digital converters; and

providing optical isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and embedded controller interface.

13. The data acquisition and control process of claim 12, wherein said controller synchronizes reading of said A/D converter with each stepper motor position;

and wherein each A/D conversion recorded by said controller is precisely tracked to a specific wavelength.

14. The data acquisition and control process of claim 12, further comprising the step of:

providing a closed loop motor position controller.

15. The data acquisition and control process of claim 14, said closed loop motor position controller comprising the steps of:

providing a digital position encoder is coupled to a stepper motor shaft; and

providing a bipolar stepper motor drive.

16. The data acquisition and control process of claim 15, wherein an encoded position signal is processed by said digital position encoder at said bipolar stepper motor drive to provide actual position feedback to said controller.

17. The data acquisition and control process of claim 16, wherein said controller initiates a next step command as soon as said position feedback reaches its target.

18. A data acquisition and control process for a precision instrument, comprising the steps of:

providing a monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

providing an analog-to-digital converter;

providing an embedded closed loop motor position controller; and

providing optical Isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and controller interface.

19. The data acquisition and control process of claim 18, said closed loop motor position controller comprising:

a digital position encoder is coupled to a stepper motor shaft; and

a bipolar stepper motor drive.

20. The data acquisition and control process of claim 19, wherein an encoded position signal is processed by said digital position encoder at said bipolar stepper motor drive to provide actual position feedback to said controller.

21. The data acquisition and control process of claim 20, wherein said controller initiates a next step command as soon as said position feedback reaches its target.

22. A data acquisition and control process for a precision instrument, comprising the steps of:

providing a monochromator, said monochromator including a stepper motor for controlling the wavelength of said monochromator'"'"'s optical output;

providing an analog-to-digital converter; and

providing optical isolation for minimizing stepper motor noise, wherein said optical isolation is provided at a bipolar stepper motor drive and embedded controller interface.