发明名称 |
SELF-CHECKING LIGHT CURTAIN SYSTEM AND METHOD OF OPERATION |
摘要 |
A light curtain system and method of operation which detects the intrusion of objects into a protected zone. The system is characterized in having an inherent self-checking mode of operation by logic circuits which analyze data signals from both the LED light transmitters and phototransistor receiver circuits. A shutdown signal is generated if the logic circuit determines that light is not received in a selected channel at the time that the LED is strobing light exclusively for that channel. The system further provides a relatively simple and inexpensive method of selecting and amplifying the LED transmitters and PT receivers. In the circuit each PT acts as a switch which selects itself, and a single amplifier is employed for a plurality of the channels. The circuit further provides for the concatenation of groups of amplifier/PT circuits into a longer chain using a single diode. |
申请公布号 |
GB2242742(A) |
申请公布日期 |
1991.10.09 |
申请号 |
GB19910000156 |
申请日期 |
1991.01.04 |
申请人 |
* SCIENTIFIC TECHNOLOGIES INCORPORATED |
发明人 |
DAVID * BLAU |
分类号 |
F16P3/14;G01V8/20;G08B13/186 |
主分类号 |
F16P3/14 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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