Safety photoelectric switch

• US 8,648,292 B2
• Filed: 03/08/2013
• Issued: 02/11/2014
• 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:
  US13/790,435
• Publication Number:
  US 20130187032A1
• Time in Patent Office: 340 Days
• Field of Search: 250/221, 250/222.1, 250/206.1, 700/21, 700/79, 700/80, 700/81, 702/155, 702/158, 702/159, 340/555, 340/556, 340/557
• 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 safety photoelectric switch comprising:

a distance measuring unit configured to optically measure a distance of an object;

a position recognizer configured to recognize a position of the object based upon the distance of the object;

a memory configured to store a protection area, at least partial of the protection area being designated as a muting area;

a signal receiver configured to receive a respective external signal from each of at least two external mute sensors,

a muting determination unit configured to determine a muting period based upon the respective external signal, a muting start criteria and a muting completion criteria;

a safety output controller configured to determine whether a safety output signal is ON or OFF based upon the position of the object and the protection area; and

wherein during the muting period determined by the muting determination unit, the safety output controller determines whether a safety output signal is ON or OFF based upon the position of the object and the protection area excluding the muting area.

2. The safety photoelectric switch according to claim 1, wherein the muting area is configurable and the configurable muting area includes a far end of the protection area.

3. The safety photoelectric switch according to claim 1, wherein the memory further stores the muting start criteria and the muting completion criteria.

4. The safety photoelectric switch according to claim 3, wherein the muting start criteria and the muting completion criteria are configurable.

5. The safety photoelectric switch according to claim 1, the safety photoelectric switch further comprising a first safety output system configured to output a safety output signal in accordance with the safety signal determined by the safety output controller;

and a second output system configured to output a safety output signal.

6. The safety photoelectric switch according to claim 1, wherein the memory stores a plurality of muting areas.

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

storing a protection area, at least partial of the protection area being designated as a muting area;

optically measuring a distance of an object;

recognizing a position of the object based upon the distance of the object;

receiving a respective external signal from each of at least two external mute sensors,

determining a muting period based upon the respective external signal, a muting start criteria and a muting completion criteria;

determining whether a safety output signal is ON or OFF based upon the position of the object and the protection area; and

wherein during the muting period, determining whether a safety output signal is ON or OFF based upon the position of the object and the protection area excluding the muting area.