Safety photoelectric switch

• US 8,415,609 B2
• Filed: 12/23/2009
• Issued: 04/09/2013
• Est. Priority Date: 01/31/2009
• Status: Active Grant

• Current Assignee: Keyence Corporation (Keyence)
• Original Assignee: Keyence Corporation (Keyence)
• Inventors: Kawabata, Shinji, Inoue, Tetsu
• Primary Examiner(s): LEE, JOHN R
• Application Number:
  US12/646,102
• Publication Number:
  US 20100198365A1
• Time in Patent Office: 1,203 Days
• Field of Search: 250/222.1, 250/221, 700/21, 700/79, 700/80, 700/81
• US Class Current: 250/221
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S17/46
• CPC Class Codes: G01S 2007/4975 of sensor obstruction by, e.g. dirt- or ice-coating, e.g. by reflection measurement on front-screen
• CPC Class Codes: G01S 7/4812 transmitted and received beams following a coaxial path
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G01S 7/484 Transmitters
• CPC Class Codes: G01S 7/4868 Controlling received signal intensity or exposure of sensor
• CPC Class Codes: G01S 7/497 Means for monitoring or calibrating
• CPC Class Codes: G01V 8/14 using reflectors
• CPC Class Codes: G01V 8/18 using mechanical scanning systems
• CPC Class Codes: G01V 8/20 using multiple transmitters or receivers
• CPC Class Codes: G05B 9/02 electric

Abstract

A photoelectric switch reduces a cost load of a user while ensuring its protection function inherent to safety equipment without impairing its safety function, and an optical scanning type photoelectric switch is provided with a muting function settable by the user, which is a function of temporarily invalidating sensing of part or the whole of a protection area, and is provided with two output systems, with respect to each of which the muting function is settable and on each output of which an inspection signal is superimposed at a different timing in a time-division manner.

Claims

1. A photoelectric switch comprising:

an optical scanner configured to optically scan a measurement area including a protection area, and obtain a light reception signal representing a position of an object at the measurement area;

a memory configured to store a first protection area and at least one of a second protection area and a safety function associated with at least one of a muting function and an interlock function;

a controller configured to determine either an ON state or an OFF state as a first safety signal representing permission/non-permission of operation for an external equipment based upon the position of the object and the first protection area, and determine either an ON state or an OFF state as a second safety signal representing permission/non-permission of operation for an external equipment based upon the position of the object and the at least one of the second protection area and the safety function associated with the at least one of the muting function and the interlock function; and

a plurality of output systems including a first output system configured to output the first safety signal and a second output system configured to output the second safety signal.

2. The photoelectric switch according to claim 1, wherein the first output system having a first line corresponding to the first safety signal and a second output line corresponding to the first safety signal, the second output system having a third output line corresponding to the second safety signal and the fourth output line corresponding to the second safety signal, and an inspection signal is superimposed on each of the first output line, the second output line, the third output line and the fourth output line at a different timing in a time-division manner.

3. The photoelectric switch according to claim 1, wherein

the memory is configured to store further a detection capability of the photoelectric switch

with respect to each of the first output system and the second output system.

4. The photoelectric switch according to claim 1, wherein the safety function is the interlock function which prevents a change in safety output of the photoelectric switch from an OFF state to an ON state.

5. The photoelectric switch according to claim 1, wherein the photoelectric switch is a multi-optical axis photoelectric switch or an optical scanning type photoelectric switch.

6. The photoelectric switch according to claim 5, wherein the safety function is the muting function which temporarily invalidates optical axes of the whole or part of optical axes of the multi-optical axis photoelectric switch or the optical scanning type photoelectric switch.

7. The photoelectric switch according to claim 6, wherein whether or not to fix to a safety signal indicating non-permission is settable by the user with respect to each output system.

13. A safety control method using a photoelectric switch, comprising:

providing the photoelectric switch according to claim 1 that is an optical scanning type photoelectric switch, the first protection area set adjacently to a danger source and the second protection area set on the periphery of the first protection area being settable by the user as protection areas of the optical scanning type photoelectric switch;

outputting the first safety signal related to the first protection area by the first output system and the second safety signal related to the second protection area by the second output system among outputs of a plurality of systems of the optical scanning type photoelectric switch;

setting a detection capability of the first output system relatively low by the user and a detection capability of the second output system relatively high; and

upon receiving the outputs from the first and second output systems, causing the danger source to emergently halt when receiving the first safety signal from the first output system and to decrease a working speed thereof when receiving the second safety signal from the second output system.

14. The photoelectric switch according to claim 1, wherein the memory configured to store the first protection area, the second protection area and the safety function associated with at least one of the muting function and the interlock function, and

the controller configured to determine either an ON state or an OFF state as the second safety signal based upon the position of the object, the second protection area and the safety function associated with the at least one of the muting function and the interlock function.

15. The photoelectric switch according to claim 14, wherein the controller configured to determine either an ON state or an OFF state as the first safety signal based upon the position of the object, the first protection area and the safety function associated with the at least one of the muting function and the interlock function.

16. The photoelectric switch according to claim 1, wherein the memory configured to store the first protection area and the safety function associated with at least one of the muting function and the interlock function, and

the controller configured to determine either an ON state or an OFF state as the second safety signal based upon the position of the object, the first protection area and the safety function associated with the at least one of the muting function and the interlock function.

17. The photoelectric switch according to claim 16, wherein the safety function includes a first safety function and a second safety function, the memory configured to store the first safety function and the second safety function as the safety function, the controller configured to determine either an ON state or an OFF state as the first safety signal based upon the position of the object, the first protection area and the first safety function associated with the at least one of the muting function and the interlock function and determine either an ON state or an OFF state as the second safety signal based upon the position of the object, the first protection area and the second safety function associated with the at least one of the muting function and the interlock function.

8. A photoelectric switch comprising:

an optical scanner configured to optically scan an measurement area including a protection area, and obtain a light reception signal representing a position of an object at the measurement area;

a memory configured to store a first detection capability and a second detection capability;

a controller configured to determine either an ON state or an OFF state as a first safety signal representing permission/non-permission of operation for an external equipment based upon the position of the object, a protection area and the first detection capability, and determine either an ON state or an OFF state as a second safety signal representing permission/non-permission of operation for an external equipment based upon the position of the object, a protection area and the second detection capability, and

a plurality of output systems including a first output system configured to output the first safety signal and a second output system configured to output the second safety signal.

9. The photoelectric switch according to claim 8, wherein the first output system having a first line corresponding to the first safety signal and a second output line corresponding to the first safety signal, the second output system having a third output line corresponding to the second safety signal and the fourth output line corresponding to the second safety signal, and an inspection signal is superimposed on each of the first output line, the second output line, the third output line and the fourth output line at a different timing in a time-division manner.

10. The photoelectric switch according to claim 8, wherein the detection capability is a response time taken for determination of changing the state of the safety signal after sensing of the position of the object.

11. The photoelectric switch according to claim 8, wherein the detection capability is a size of a minimal detected object indicating a minimal size among sizes of detected objects detectable by the photoelectric switch.

12. The photoelectric switch according to claim 8, wherein the detection capability is a light reception sensitivity of the photoelectric switch.