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US 8,576,072 B2Granted
Optoelectronic sensor
AssigneeSick AG
InventorMichael Klein
Life of this patent
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AssigneeSick AG
InventorMichael Klein
Estimating the term…
An optoelectronic sensor (10) is provided with a light transmitter (12) for transmitting a light signal (16) into a monitoring area (18), a light receiver (26) for receiving and converting the light signal (22) remitted or reflected from an object (20) in the monitoring area (18) into a reception signal, a switching output (30) for the output of a switching signal when the reception signal meets a switching criterion (E), a pre-failure alarm output (32) for the output of a pre-failure alarm signal, and an evaluation unit (28) configured to detect a contamination state that is present when the reception signal meets a contamination criterion (C) but not the switching criterion (E) and to output a pre-failure alarm signal when a contamination period during which the contamination state extends for more than a tolerated period (TPFA,ON) and/or when a contamination state occurrence number that is incremented upon each entry of the contamination state is larger than a tolerated number. The evaluation unit (28) is further configured to add up the contamination period also across several discontinuous periods of the contamination state or to count the contamination state occurrence number also across periods during which neither the switching criterion (E) nor the contamination criterion (C) are met, respectively.
An optoelectronic sensor (10) with a light transmitter (12) for transmitting a light signal (16) into a monitoring area (18), a light receiver (26) for receiving and converting the light signal (22) remitted or reflected from an object (20) in the monitoring area (18) into a reception signal, a switching output (30) for the output of a switching signal when the reception signal meets a switching criterion (E), a pre-failure alarm output (32) for the output of a pre-failure alarm signal, and an evaluation unit (28) configured to detect a contamination state that is present when the reception signal meets a contamination criterion (C) but not the switching criterion (E) and to output a pre-failure alarm signal when a contamination period during which the contamination state extends for more than a tolerated period (TPFA,ON) and/or when a contamination state occurrence number that is incremented upon each entry of the contamination state is larger than a tolerated number, characterized in that the evaluation unit (28) is configured to add up the contamination period also across several discontinuous periods of the contamination state or to count the contamination state occurrence number also across periods during which neither the switching criterion (E) nor the contamination criterion (C) are met, respectively.
Method for monitoring a monitoring area (18), in which a light signal (16) is transmitted into the monitoring area (18), the light signal (22) remitted or reflected from objects (20) in the monitoring area (18) is received and converted into a reception signal, wherein a switching signal is output at a switching output (30) when the reception signal meets a switching criterion (E), wherein a contamination state is detected when the reception signal meets a contamination criterion (C) but not the switching criterion (E), and wherein a pre-failure alarm signal is output at a pre-failure alarm output (32) when a contamination period during which the contamination state is present extends for more than a tolerated period (TOFA,ON) and/or when a contamination state occurrence number that is incremented upon each entry of the contamination state is larger than a tolerated number, characterized in that the contamination period is added up also across several discontinuous periods of the contamination state or that the contamination state occurrence number is counted also across periods during which neither the switching criterion (E) nor the contamination criterion (C) are met, respectively.
Dependencies are inferred from the claim text.