JPS6324555Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an optical transmission type alarm device that performs intensive monitoring of fire, theft, etc. using an optical transmission system consisting of an optical detector and an optical cable.

Generally, transmission between a transmission system receiver and multiple terminal devices, such as smoke detectors and theft detectors, was performed using electrical signals, but in recent years, optical fiber cables (known as optical transmission cables) Due to the cost reduction and quality improvement associated with the mass production of optical cables (hereinafter referred to as "optical cables"), it is being considered to incorporate optical transmission systems into this type of alarm device.

By the way, it is relatively easy to replace only the transmission system with an optical cable by reusing general optical communication technology, but it is difficult to replace the terminal equipment used in this type of alarm device, such as a smoke detector, etc. teeth,
The sensor itself must be powered, and
Since it is necessary to identify and display the detection output from multiple sensors on the receiver side, conventionally, an optical cable was used only to transmit the detection signal from the sensor to the receiver. It is a complex system, and the advantages of the optical system have not yet been fully utilized.

This invention was made in view of the above, and in order to simplify the system configuration by configuring it with a pure optical system,
Light with a frequency spectrum that includes multiple predetermined natural frequencies is transmitted from the receiver side to the warning area via one optical cable, and light with predetermined natural frequencies is demultiplexed from this transmitted light and detected by a photodetector. In addition to being used as a light source, the output light from the photodetector is mixed with the other cable and transmitted to the receiver, where the light with a unique frequency is demultiplexed and converted into an electrical signal, and an alarm is issued based on this signal. It is designed to be displayed.

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings. The figure shows a block diagram of an alarm system as an embodiment of the present invention, where 1 is a multi-frequency light source installed in a receiver R that emits multi-frequency light, and 2a and 2b are light sources with predetermined frequencies. 12 is an optical fiber cable that connects the multi-frequency light source 1 and the splitter, 3a is a dimming type smoke detector that reduces the amount of light received when smoke enters, and 3b is a dimming type smoke detector that reduces the amount of light received when smoke enters. This is a scattered light type smoke detector that detects the scattered light when it hits the smoke. Each sensor 3a,
3b, the light emitting parts 14a, 15a and the light receiving part 14b,
15b. 4a and 4b are mixers for mixing light, which mix the lights from the light receiving sections 14b and 15b into the optical fiber cable 13 and transmit the mixed light to the receiver R. Receiver R has optical fiber cable 1
a demultiplexer 5 that demultiplexes the light received through the demultiplexer 3 into light that is preassigned to each terminal; and photoelectric converters 16a to 16 that convert the demultiplexed output from the demultiplexer 5 into electrical signals.
n, level adjustment circuits 6a to 6n that adjust the photoelectric conversion signal to a predetermined level; level adjustment circuits 6a to 6;
a comparison circuit 7 that compares the output of n based on the reference signal from the reference value setting circuit 8; and a reception processing circuit 11 that displays an alarm on the display 9 and rings a bell 10 based on the comparison output from the comparison circuit 7. is provided.

Next, the operation of the embodiment of the present invention configured as described above will be explained.

Light from a multi-frequency light source 1 that emits light of various frequencies emitted by a small number of light sources with a wide light emission frequency spectrum or light sources of each frequency is passed through an optical fiber cable 12 to a demultiplexer 2a to 2a. 2n. The demultiplexers 2a to 2n demultiplex the light from the light source, and for example,
In case a, the light of ₁ is separated, and in the case of a scattered light type smoke sensor, the light of ₂ is separated, and in the same way, light of a unique frequency is separated for a large number of sensors (not shown). The demultiplexed light is emitted from the light emitting sections 5a, 6a, etc. to the smoke detection area or warning area.

In the dimming type smoke detector 3a, when there is no fire, that is, when there is no inflow of smoke, the light from the light emitting part 5a enters the light receiving part 14b as it is.
The light of frequency ₁ received by the optical fiber 4b is mixed with the light from other photodetectors into the optical fiber cable 13 for transmission by the mixer 4a via the optical fiber cable 13', and then sent to the demultiplexer 5 of the receiver R. The light is demultiplexed into light having a frequency of ₁ , converted into an electrical signal of a predetermined level by a photoelectric converter 16a and a level adjustment circuit 6a, and input to a comparison circuit 7. The reference signal from the reference value setting circuit 8 for the received light signal of frequency ₁ is determined according to the dimming type smoke detector 3a, and is sent to the comparison circuit 7 when the smoke density exceeds a predetermined value. Fire detection is performed by setting a reference value so that a comparison output is generated when the input signal is below a predetermined level.

On the other hand, regarding the scattered light type smoke detector 3b, when there is no inflow of smoke and there is no fire, there is no scattered light entering the light receiving part 15b, so the demultiplexer of the receiver R that demultiplexes this light of frequency ₂ Therefore, the reference value predetermined circuit 8 sets a comparison reference value so as to generate a comparison output when the received light signal level of frequency ₂ exceeds a predetermined _value . When the scattered light of . In this way, the light output detected by the photodetector of the terminal varies depending on the structure or purpose of the detector, so the reference value of the receiver R is set accordingly. The circuit 8 is set as the comparison circuit 7.

The embodiment shown in the figure shows one system using a pair of optical fiber cables 12 and 13.
Of course, a plurality of circuit units and optical systems other than the reception processing circuit 11, display 9, and bell 10 may be provided for the reception processing circuit 11.

Further, as the photodetector provided in the terminal, in addition to the above-mentioned optical smoke detector, an appropriate photodetector such as a photoelectric theft switch may be provided.

As explained above in detail, according to the present invention,
Light with multiple frequencies is split into light with each unique frequency using a demultiplexer, and the detector uses the light of the unique signal to detect fires. In addition to being able to accurately determine the location of occurrence of such problems, the alarm system can be configured with a simple configuration because light of several frequencies is transmitted through the same cable, and since it is processed purely optically, it is reliable. It has an excellent effect of being able to perform detection.

[Brief explanation of the drawing]

The figure is a system block diagram showing an embodiment of the present invention. R... Receiver, 1... Light emitting source, 2a, 2b, 5
...Dunplexer, 3a, 3b...Light emitting section, 4a, 4b
...Mixer, 6a-6n...Level adjuster, 7...
... Comparison circuit, 8 ... Reference value setting circuit, 9 ... Display, 10 ... Bell, 11 ... Reception processing circuit, 1
2, 13, 12', 13'...Optical fiber cable, 14a, 15a...Light emitting part, 14b, 15b
... Light receiving section, 16a to 16n ... Photoelectric converter.

Claims (1)

[Claim for Utility Model Registration] A pair of optical cables drawn out from a receiver are laid in a predetermined warning area, and a plurality of demultiplexers that separate light with a predetermined natural frequency are connected in series to one of the optical cables. At the same time, a plurality of mixers for mixing the light demultiplexed by the demultiplexer into the optical cable are connected in series to the other of the optical cables, and a transmission signal is transmitted between the corresponding pair of demultiplexers and the mixer. A light type or scattered light type photodetector is provided, the photodetector uses light at the natural frequency as a light source, and the receiver has a frequency spectrum that includes at least the natural frequency assigned to the splitter. a light emitting source that enters light into one of the optical cables;
a demultiplexer that demultiplexes the light from the mixer transmitted via the optical cable for each natural frequency; a photoelectric converter that converts each demultiplexed output light of the demultiplexer into an electrical signal; 1. An optical transmission alarm device comprising: a comparison circuit that compares a change output signal of a converter with a predetermined reference value; and an alarm display circuit that displays an alarm based on the output of the comparison circuit.