Programmed method and apparatus for quadrature output sensors

• US 7,310,587 B2
• Filed: 05/12/2004
• Issued: 12/18/2007
• Est. Priority Date: 12/12/2001
• Status: Expired due to Fees

• Current Assignee: Balluff Incorporated
• Original Assignee: Balluff Incorporated
• Inventors: Topmiller, David Allen
• Primary Examiner(s): Bui, Bryan
• Application Number:
  US10/844,227
• Publication Number:
  US 20040208473A1
• Time in Patent Office: 1,315 Days
• Field of Search: 702/150, 702/66, 702/67, 702/71, 702/75, 702/107, 702/104, 702/57, 702/85, 702/89, 702/198
• US Class Current: 702/150
• CPC Class Codes: G01D 18/001 Calibrating encoders
• CPC Class Codes: G01D 5/2448 Correction of gain, threshold, offset or phase control
• CPC Class Codes: G01D 5/2449 using hard-stored calibration data

Abstract

A sensor is provided in one illustrative embodiment that includes a microcontroller that executes a program that generates quadrature output signals that indicate the change in a parameter being measured. As an example, the sensor could comprise a linear position transducer. The quadrature output signals can comprise square wave signals that are ninety degrees out of phase, each transition of the signals representing a unit of change in position of the measured mass. According to another aspect, the quadrature signals can be placed into phase with one another to indicate an error condition. In another aspect, user inputs can be provided to allow the user to select parameters such as frequency, update rate, and/or resolution. Moreover, at least one of the sensor inputs can be utilized to load calibration factor data for the sensor.

Claims

1. A method in a sensor for generating incremental output signals indicating the change in a parameter, the method comprising:

providing a signal representing a value of the parameter;

using a program to determine a number of transitions to provide based upon the change in the value of the parameter; and

using the program to switch at least one incremental output signal based upon the number of transitions determined, such that the number of transitions in the incremental output signal represents the change in parameter.

2. The method as recited in claim 1, wherein the at least one incremental output signal comprises a pair of square wave signals approximately ninety degrees out of phase from one another.

3. The method as recited in claim 1, wherein the sensor comprises a linear position transducer and the signal comprises a position signal.

4. A storage medium having stored executable instructions for performing a method for generating quadrature output signals indicating the change in a measured parameter, the method comprising:

determining a transition count based upon the change in the measured parameter;

determining the direction of the change in the parameter; and

generating a pair of quadrature pulse signals such that the number of transitions in the quadrature pulse signals is substantially equal to the transition count, and such that the phase of the pulse signals is offset based upon the direction determined whereby the pulse signals represent the change in the measured parameter, wherein the stored instructions cause the generation of the quadrature pulse signals.

5. The medium as recited in claim 4, wherein the generating operation comprises:

if the change in the measured parameter is negative, generating the pulse signals such that one of the signals having a designation of A lags in phase the other pulse signal having a designation of B; and

if the change in the measured parameter is positive, generating the pulse signals such that one of the signals having a designation of A leads in phase the other pulse signal having a designation of B.

6. The medium as recited in claim 4, wherein the generating operation comprises:

determining the number of transitions needed to place the pulse signals at a predetermined state;

switching the pulse signals to reach that state;

switching the pulse signals in a loop a number of times based upon the transition count; and

switching the pulse signals any remaining times needed.

7. The medium as recited in claim 4, wherein the method further comprises:

providing a predetermined output signal whenever a predetermined value of the measured parameter is reached, wherein the predetermined value is user definable via a user input.

8. A method for providing output signals in a quadrature output device, the method comprising:

providing a measurement signal indicating a value of a measured parameter;

generating a pair of signals having a number of transitions, wherein the number of transitions in the signals is proportional to the change in measurement signal;

detecting whether an error has occurred;

if an error has occurred, causing a simultaneous transition of the pair of signals; and

if an error has not occurred, maintaining a timing offset in the transitioning of the signals.

9. The method as recited in claim 8, wherein the pair of signals comprises square waves which are approximately ninety degrees out of phase from one another, but are in phase during the causing operation.

10. A method for providing output signals from a sensor, the method comprising:

receiving at least one input from a user indicating a user selection;

modifying a program setting based upon the user selection;

providing a measurement signal indicating a value of a measured parameter;

determining the value of the measured parameter; and

using the program, generating a pair of signals having a number of transitions, the number of transitions in the signals representing the value of the measured parameter.

11. The method as recited in claim 10, wherein the pair of signals comprise square waves which are approximately ninety degrees out of phase from one another, and wherein the number of transitions in the signals is directly proportional to the change in the measured parameter.

12. The method as recited in claim 10, wherein the program setting comprises at least one of the frequency of the signals, the number of transitions of the signals per unit of measured parameter, and the frequency of the generation operation.

13. A method for calibrating a sensor, the method comprising:

testing the sensor to determine calibration factor data, wherein the sensor includes at least one input that is normally used to receive a command signal from an external control device;

connecting a calibration device to the at least one sensor input that is normally used to receive a command signal from an external control device; and

loading calibration factor data from the calibration device over the at least one sensor input that is normally used to receive a command signal from an external control device;

wherein the sensor comprises a quadrature output sensor.

14. The method as recited in claim 13, further comprising:

connecting the calibration device to at least one sensor output that is normally used to provide a measurement signal from the sensor; and

transferring parameters from the sensor to the calibration device using the at least one output.