Method for operating optical sensors

• US 20040184041A1
• Filed: 01/29/2004
• Published: 09/23/2004
• Est. Priority Date: 02/01/2003
• Status: Active Grant

• Current Assignee: Sick AG (Sick)
• Original Assignee: Sick AG (Sick)
• Inventors: Schopp, Thomas
• Granted Patent: US 7,214,954 B2
• Time in Patent Office: Days
• US Class Current: 356/625
• CPC Class Codes: G01B 11/04 specially adapted for measuring length or width of objects while moving

Abstract

A method for operating an optical sensor for measuring a physical quantity with a defined scale value that is subject to a calibration certification. The measurement accuracy of the quantity being measured is dependent on at least one external condition, and a given scale value is used for the measurement according to the desired measurement accuracy. The scale value is appropriately changed when the measurement accuracy changes due to a change of external condition. An optoelectronic sensor has a switching arrangement for changing the scale value. The sensor is more diversified and can cover larger measurement ranges without requiring new certifications or authorizations for the different measurement ranges.

Claims

1. A method of operating an optical sensor for measuring a physical quantity of an object by means of a defined scale value subject to a calibration certification, comprising establishing a measurement accuracy for the quantity being measured in dependency of at least one external condition, using a scale value for measuring the quantity as a function of a desired measurement accuracy, and switching the scale value in response to a change in the measurement accuracy caused by the at least one external condition.

2. A method according to claim 1 including deriving the external condition from a geometrical property of the object.

3. A method according to claim 1 including deriving the external condition from a position of the object.

4. A method according to claim 1 including manually entering the external condition into the optical sensor.

5. A method according to claim 1 including recognizing the external condition with the optical sensor.

6. A method according to claim 1 including automatically switching the scale value as a function of the external condition.

7. A method according to claim 1 including detecting the at least one parameter representing the external condition and automatically switching the scale value in response to a defined change in the at least one parameter.

8. A method according to claim 6 wherein the parameter is a speed of a conveyor and the optical sensor measures at least one dimension of goods being delivered by a conveyor.

9. An optoelectronic sensor for measuring a physical quantity comprising a detector for detecting a physical quantity in dimensional units of a calibratable scale value, and a switch for changing the scale value.

10. An optoelectronic sensor according to claim 9 wherein the switch automatically changes the scale value.

11. An optoelectronic sensor according to claim 9 including an arrangement for deriving the external condition from a geometrical property of the object.

12. An optoelectronic sensor according to claim 9 including an arrangement for deriving the external condition from a position of the object.

13. An optoelectronic sensor according to claim 9 including an arrangement for manually entering the external condition into the sensor.

14. An optoelectronic sensor according to claim 9 including an arrangement for automatically recognizing the external condition with the sensor.

15. An optoelectronic sensor according to claim 9 including an arrangement for detecting at least one parameter representing an external condition.

16. An optoelectronic sensor according to claim 15 wherein the parameter is the transport speed of a conveyor and the sensor measures at least a length of goods being transported by the conveyor.