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公开(公告)号：EP0241574B1
公开(公告)日：1997-10-29
申请号：EP86107379.9
申请日：1986-05-30
CPC分类号： G08B17/00 , G08B26/002
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公开(公告)号：EP0241574A3
公开(公告)日：1989-03-22
申请号：EP86107379.9
申请日：1986-05-30
CPC分类号： G08B17/00 , G08B26/002
摘要： An improved fire alarm system utilizes receiver (10) and fire detecting terminals (20) connected thereto through a signal transmission line (1) comprising two wires. The fire detecting terminal operates on two mode, one being a contact-closure mode of transmitting to the receiver a level signal whether or not a significantly higher fire-indicative quantity is detected, and the other being intelligent mode of transmitting a digital signal indicative of the sensed quantity in the form of a superimposed signal upon the level signal in answer to the instruction from the receiver for precise and convenient analysis thereof in determining fire presence on the side of the receiver. The fire detecting terminal includes a comparator having its own threshold with which the value of the sensed analog quantity is compared for providing the level-shifted signal when the sensed analog quantity has a level higher than the threshold, notifying fire presence independently of the intelligent mode. The threshold level can be selected independently of a criterion utilized in determining fire presence based upon the digital signal on the receiver, so that the above two modes can have the same sensitivity against possible fires. Accordingly, the contact-closure mode can well stand for a back-up fire detection without reduction in sensitivity.
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公开(公告)号：EP0241574A2
公开(公告)日：1987-10-21
申请号：EP86107379.9
申请日：1986-05-30
CPC分类号： G08B17/00 , G08B26/002
摘要： An improved fire alarm system utilizes receiver (10) and fire detecting terminals (20) connected thereto through a signal transmission line (1) comprising two wires. The fire detecting terminal operates on two mode, one being a contact-closure mode of transmitting to the receiver a level signal whether or not a significantly higher fire-indicative quantity is detected, and the other being intelligent mode of transmitting a digital signal indicative of the sensed quantity in the form of a superimposed signal upon the level signal in answer to the instruction from the receiver for precise and convenient analysis thereof in determining fire presence on the side of the receiver. The fire detecting terminal includes a comparator having its own threshold with which the value of the sensed analog quantity is compared for providing the level-shifted signal when the sensed analog quantity has a level higher than the threshold, notifying fire presence independently of the intelligent mode. The threshold level can be selected independently of a criterion utilized in determining fire presence based upon the digital signal on the receiver, so that the above two modes can have the same sensitivity against possible fires. Accordingly, the contact-closure mode can well stand for a back-up fire detection without reduction in sensitivity.
摘要翻译： 改进的火灾报警系统通过包括两条电线的信号传输线（1）利用与其相连的接收器（10）和火情检测端子（20）。 火灾检测终端在两种模式下操作，一种是向接收机发送一个电平信号的接触闭合模式，无论是否检测到显着更高的火灾指示量，另一种是发送指示 响应于来自接收机的指令的电平信号的叠加信号的形式的感测量，以便在确定接收机侧的火灾存在时进行精确和方便的分析。 火灾检测终端包括具有其自己的阈值的比较器，当感测到的模拟量具有高于阈值的电平时，将感测的模拟量的值与其进行比较，以提供电平移位的信号，独立于智能模式通知火灾存在 。 可以独立于基于接收机上的数字信号确定火灾存在的标准来选择阈值水平，使得上述两种模式对于可能的火灾具有相同的灵敏度。 因此，接触闭合模式可以很好地代表备用火灾检测，而不降低灵敏度。
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