Sensor with improved gain-setting capability

• US 7,232,984 B2
• Filed: 04/15/2005
• Issued: 06/19/2007
• Est. Priority Date: 04/15/2005
• Status: Expired due to Fees

• Current Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Allen-Bradley Co., Inc.)
• Inventors: Rollins, George E.
• Primary Examiner(s): Luu; Thanh X.
• Assistant Examiner(s): ELLIS, SUEZU Y
• Application Number:
  US11/107,071
• Publication Number:
  US 20060231743A1
• Time in Patent Office: 795 Days
• Field of Search: 250/214.AG, 250/214.R, 250/214.A, 250/214.AL, 250/221, 455/240.1, 455/138, 327/514
• US Class Current: 250/214.0AG
• CPC Class Codes: G01J 1/08 Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
• CPC Class Codes: G01J 1/44 Electric circuits for command of an exposure part G03B7/02
• CPC Class Codes: G01V 13/00 Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00

Abstract

A method of calibrating a sensor such as a photodetector, and device capable of employing that method, are disclosed. The method includes shining light upon a photosensitive device of the photodetector, receiving a first signal from an operator, and increasing a gain of the photodetector. The method also includes discontinuing the shining of the light upon the photosensitive device after the gain has been increased, receiving a second signal from an operator, and decreasing the gain so that the gain is not excessive.

Claims

1. A method of setting an operational characteristic of a sensor, the method comprising:

exposing the sensor to a first sensory condition;

receiving a first signal from at least one of an operator and a control device;

receiving a first sensor signal from the sensor subsequent to the receiving of the first signal;

adjusting a characteristic of the sensor in a first manner, wherein the characteristic is a gain, and wherein the adjusting in the first manner involves incrementing the gain;

exposing the sensor to a second sensory condition after the characteristic has been adjusted in the first manner;

receiving a second signal from at least one of the operator and the control device;

receiving a second sensor signal from the sensor subsequent to the receiving of the second signal;

generating an amplified signal based upon the second sensor signal, the amplified signal being related to the second sensor signal by the incremented gain; and

adjusting the characteristic in a second manner in at least one circumstance, wherein the adjusting in the second manner involves decrementing the gain, wherein the at least one circumstance occurs when the amplified signal exceeds a threshold.

2. The method of claim 1, wherein the sensor is a photodetector, the exposing of the sensor to the first sensory condition involves shining of light from a light source upon a photosensitive device of the sensor, and the exposing of the sensor to the second sensory condition involves discontinuing the shining of the light.

3. The method of claim 1, wherein the sensor is a proximity detector, the exposing of the sensor to the first sensory condition involves placement of a target object at a location proximate to the proximity detector, and the exposing of the sensor to the second sensory condition involves removal of the target object away from the location and away from the proximity detector.

4. A method of calibrating a photodetector, the method comprising:

shining light upon a photosensitive device of the photodetector;

receiving a first signal from an operator;

adjusting a gain of the photodetector in a first direction upon the receiving of the first signal;

discontinuing the shining of the light upon the photosensitive device after the gain has been adjusted in the first direction;

receiving a second signal from the operator; and

adjusting the gain in a second direction upon the receiving of the second signal so that the gain meets a desired condition.

5. The method of claim 4, wherein the first and second signals are received in response to the pressing and releasing of a button on the photodetector by the operator.

6. The method of claim 4, wherein the adjusting of the gain in the first direction is an incrementing of the gain, the adjusting of the gain in the second direction is a decrementing of the gain, and the gain is adjusted in the second direction until the gain is no longer excessive as determined in relation to a threshold.

7. The method of claim 6, wherein an indication is provided once the gain has been increased that it is appropriate for the shining of the light to be discontinued.

8. The method of claim 7, wherein the indication is flashing on and off of a light-emitting diode on the photodetector, and wherein the gain is set to a minimum level upon initially receiving the first signal prior to the increasing of the gain.

9. The method of claim 6, wherein the gain is decreased when an amplified signal generated by the photodetector when the shining of the light has been discontinued exceeds a threshold, and wherein a gain setting is stored in a memory after the gain has been adjusted.

10. The method of claim 6, wherein the incrementing of the gain involves an increment to a gain factor of approximately 5, and wherein at least one of the first and second signals is received at the photodetector by way of a wireless transmission.

11. The method of claim 4, wherein the method is performed in conjunction with installing at least a portion of a conveyor system having the photodetector

12. The method of claim 4, further comprising:

receiving a further input signal from the operator; and

toggling an operational state of the photodetector.

13. The method of claim 12, wherein the operational state of the photodetector is toggled between a light state in which an output signal of the photodetector is indicative of an intensity of the light received at the photosensitive device and a dark state in which the output signal is indicative of a degree of absence of the light at the photosensitive device.

14. The method of claim 12, wherein an indication of the operational state of the photodetector after being toggled is stored in a memory device associated with the photodetector, and wherein the further input signal is received by at least one of the pushing and releasing of a button on the photodetector, and by way of a wireless transmission.

15. A photodetector comprising:

a photosensitive device;

at least one input device by which it is possible for an operator to provide input signals to the photodetector;

a variable-gain amplifier circuit coupled to the photosensitive device and capable of receiving signals from the photosensitive device indicative of an intensity of light received by the photosensitive device; and

a control component coupled to the variable-gain amplifier circuit and the at least one input device, wherein the control component provides signals governing the gain of the variable-gain amplifier circuit,

wherein the gain of the variable-gain amplifier circuit is set in response to two input signals provided at the at least one input device, wherein the gain is increased after one of the two input signals is provided and the gain is decreased after the other of the two input signals is provided, and wherein the one input signal occurs when the photosensitive device is exposed to a first light input and the other input signal occurs when the photosensitive device is exposed to a second light input that has an intensity level that is less than that of the first light input.

16. The photodetector of claim 15, wherein the one input signal is provided when light is shining upon the photosensitive device and the other input signal is provided when the light is not shining upon the photosensitive device.

17. The photodetector of claim 15, wherein the at least one input device includes a push button, and each of the two input signals is provided when the push button is pressed and then released.

18. The photodetector of claim 15, further comprising means for providing an indication, wherein the means for providing the indication provides an indication after the gain has been increased.

19. The photodetector of claim 15, wherein at least one of the control component and the variable-gain amplifier circuit is formed on an application specific integrated circuit.

20. The photodetector of claim 15, wherein the one input signal is provided prior to the other input signal.

21. A sensor system comprising:

a sensing device configured to provide an output signal that varies depending upon an intensity level of an input signal received by the sensing device; and

an application-specific integrated circuit (ASIC) including a variable-gain amplifier circuit coupled to the sensing device and capable of amplifying the output signal from the sensing device according to a gain of the amplifier circuit,

wherein the gain of the variable-gain amplifier circuit is determined by way of a first operation in which the gain is increased to a first level in response to the sensing device being exposed to a higher-level input signal intensity, and a second operation in which the gain is decreased to a second level in response to the sensing device being exposed to a lower-level input signal intensity, and

wherein the second operation occurs in dependence upon a comparison of an amplified signal with a threshold, and the amplified signal is generated by the variable-gain amplifier circuit based upon both the output signal when the sensing device is being exposed to the lower-level input signal intensity and the gain when increased to the first level.

22. The system of claim 21, wherein the sensing device is a photosensitive device, wherein the higher-level input signal intensity is a higher-level light intensity, and wherein the lower-level input signal intensity is a lower-level light intensity.

23. The system of claim 22, wherein the first operation only occurs after a first indication has been received indicating that the photosensitive device is being exposed to the higher-level light intensity, and wherein the second operation only occurs after a second indication has been received indicating that the photosensitive device is being exposed to the lower-level light intensity.