Sensor with improved gain-setting capability

• US 20060231743A1
• Filed: 04/15/2005
• Published: 10/19/2006
• Est. Priority Date: 04/15/2005
• Status: Active Grant

• Current Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Original Assignee: Rockwell Automation Technologies Incorporated (Rockwell Automation, Inc.)
• Inventors: Rollins, George E.
• Granted Patent: US 7,232,984 B2
• Time in Patent Office: Days
• US Class Current: 250/214.R
• 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;

adjusting a characteristic of the sensor in a first manner;

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; and

adjusting the characteristic in a second manner in at least one circumstance.

2. The method of claim 1, wherein the characteristic is a gain, the adjusting in the first manner involves incrementing the gain, the adjusting in the second manner involves decrementing the gain, and the at least one circumstance is a situation in which an amplified signal exceeds a threshold, wherein the amplified signal is determined based upon an analog signal received in response to the second sensory condition as amplified by the gain as incremented.

3. 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.

4. The method of claim 3, 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.

5. 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;

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 an operator; and

adjusting the gain in a second direction so that the gain meets a desired condition.

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

7. The method of claim 5, 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.

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

9. The method of claim 8, 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.

10. The method of claim 7, 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.

11. The method of claim 7, wherein the increasing of the gain involves an increase 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.

12. A method of installing at least a portion of a conveyor system having a photodetector unit comprising the method of claim 5.

13. The method of claim 5, further comprising:

receiving a further input signal from an operator; and

toggling an operational state of the photodetector.

14. The method of claim 13, 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.

15. The method of claim 13, 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.

16. A photodetector comprising:

a photosensitive device;

at least one input device by which its 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.

17. The photodetector of claim 16, 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.

18. The photodetector of claim 16, 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.

19. The photodetector of claim 16, further comprising means for providing an indication, wherein the means for providing the indication provides an indication after the gain has been increased.

20. The photodetector of claim 16, wherein at least one of the control component and the variable-gain amplifier circuit is formed on an application specific integrated circuit.