JP3075579B2 - Ray smoke detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam type smoke detector which receives a light beam emitted from a light emitting portion at a light receiving portion and detects a fire by a change in a light receiving output due to invasion of smoke.

[0002]

2. Description of the Related Art Conventionally, this type of photoelectric smoke detector is used for monitoring a large area such as a gymnasium.
A structure in which the light emitting unit 60 and the light receiving unit 61 are separated as shown in FIG. 6 (A), and the light emitting unit 60 and the light receiving unit 61 are installed facing each other with a predetermined monitoring distance therebetween, and the light from the light emitting unit 60 is directly received by the light receiving unit 61. And a reflector 6 provided integrally with a light emitting unit 60 and a light receiving unit 61 as shown in FIG.
There is a structure in which the light from the light emitting unit 60 is reflected by the reflecting plate 63 and the reflected light is received by the light receiving unit 61. 6 (A) and the integrated sensor of FIG. 6 (B) emit light in the near-infrared region from the light emitting unit 60 toward the light receiving unit 61 or the reflection plate 63, and a fire occurs. The light generated by the generated light is blocked,
The detection of a fire is performed by the change of the light receiving level of.

[0003] Usually, the monitoring distance of this type of sensor is 5 m to
It is 100 m, and is installed on the ceiling of the building, and after adjusting the optical axis, the light amount is adjusted. Adjustment of the light amount is generally performed by adjusting the gain of the light-receiving amplifier circuit on the light-receiving unit side. That is, the adjustment is performed so that a light reception output in a certain predetermined range is obtained.

[0004]

By the way, the gain adjustment of the light-receiving amplifier circuit of the above-mentioned conventional light beam smoke detector is performed, for example, by adjusting the gain of an amplifier circuit gain adjusting section 70 provided in the sensor as shown in FIG. Although the gain adjustment of the amplifier circuit is performed by using the setting volume 71 for adjustment and the setting volume 72 for fine adjustment, there is a problem that the operation using these volumes is extremely troublesome. This is because the monitoring distance is as large as 5 m to 100 m, and the dynamic range of the received light amount is 1.0 to 0.003 (V), which is three digits. In addition, since the current in the amplifier circuit is extremely weak, it is easily affected by noise generated from the setting volumes 71 and 72 at the time of gain adjustment, and it is difficult to perform gain adjustment accurately. Therefore, there is also a problem that the operation becomes complicated. Further, there is another problem that the cost for adjusting parts is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described conventional problems, and provides a light beam type smoke detector capable of automatically adjusting the gain of an amplifier circuit of a light receiving section. With the goal.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention is directed to a light receiving section which receives a light beam of a monitoring light emission output emitted from a light emitting section and changes the light receiving output due to the invasion of smoke. In the light beam smoke detector that performs fire detection, the light emitting output of the light emitting unit is sequentially controlled with the gain of the amplifier circuit of the light receiving unit kept constant, and the light receiving output becomes a value within a predetermined range. Setting means for setting the gain of the amplifying circuit of the light receiving unit based on a conversion table of the data and the gain of the amplifying circuit predetermined from the data at the time.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a light beam type smoke detector in which a light emitting unit and a light receiving unit are separated according to an embodiment of the present invention. In the light beam type smoke detector, the light emitting unit 1 and the light receiving unit 2 are installed so as to be opposite to each other via a predetermined monitoring distance so that the optical axes are the same.

The light emitting section 1 includes a light emitting element 10 such as an LED,
A light amount switching circuit 11 for switching the light amount of the light emitting element 10,
And a receiving circuit 12 for receiving a control signal from the light receiving section 2.

The light receiving section 2 includes a light emitting control section 21 for controlling the light emitting section 1, a light receiving element 22 for receiving light from the light emitting element 10, an amplifying circuit 23 for amplifying an output from the light receiving element 22, and an amplification circuit. An A / D converter 24 for converting an analog signal from the circuit 23 into digital light reception data, a light reception data storage 25 for storing light reception data, and a fire for determining whether the dimming rate of the light reception data is equal to or greater than a threshold value. Judgment unit 26
A light emission amount control unit 27 that changes the light emission amount of the light emitting element 10 stepwise; a gain minimum setting unit 28 that sets the gain of the amplifier circuit 23 to a minimum; and a gain control unit 29 that controls the gain of the amplifier circuit 23. A gain switching circuit 30 for actually switching the gain of the amplifier circuit 23 according to an instruction from the gain minimum setting unit 28 or the gain control unit 29; a first table 31 for storing a predetermined pattern for gain adjustment; A pattern determining unit 32 for selecting and determining the 31 patterns; and a second storing a gain value to be selected according to the determined pattern.
It comprises a table 33 and a steady light emission amount setting unit 34 for setting the light emission amount of the light emitting element 10 to a steady value. Also,
Light emission control unit 21, light receiving element 22, amplification circuit 2 of light receiving unit 2
3 and the components other than the A / D converter 24, 1
It is composed of two CPUs 40.

Here, the contents of the first table 31 are shown in FIG. In the first table 31, as shown in FIG.
The relative light amount corresponding to each step of the light amount step is set. In the light amount step, “1” is the largest light amount (this light amount is the light amount in normal monitoring), and a smaller light amount is set as the number increases. Further, the state of the change in the amount of light received by the light receiving element 22 obtained corresponding to each light amount step of the light emitting element 10 is divided into five patterns and set as a light receiving pattern. Each pattern is provided with identifiers A1 to A5, and the identifier is used to represent the pattern. Note that the pattern A1 is a pattern obtained when the distance between the light emitting unit 1 and the light receiving unit 2 is the shortest, and is a pattern obtained when the pattern A5 is the longest. In the pattern, “↑” indicates that the amount of received light is greater than a preset threshold, and “↓” indicates that the amount is less than the threshold. Further, “○” indicates that the amount of received light is within the range of the threshold. FIG. 4 shows the contents of the second table 33. In the second table 33, the magnitude of the gain to be set according to the five patterns A1 to A5 is represented by B1.
ＢB5 are set in stages. Here, the identifier B5 indicates the maximum gain, the gain gradually decreases, and the minimum gain is obtained at B1.

Next, the operation for automatically adjusting the gain of the amplifier circuit 23 of the light receiving section 2 will be described with reference to the flowchart of FIG. First, the gain switching circuit 30 is controlled by the gain minimum setting unit 28 to set the gain of the amplifier circuit 23 to the same value as the minimum gain B1 of the second table 33 (Step S).
1). Next, the light amount switching circuit 11 is controlled by a command from the light emission amount control unit 27, and the light amount of the light emitting element 10 is sequentially increased from the minimum value in accordance with the light amount step (step S2). At this time, the amount of received light that changes corresponding to the amount of emitted light is sequentially stored in the received light data storage unit 25 (step S3). The pattern determination unit 32 includes the light reception data storage unit 2
The light receiving pattern is selected by comparing the light receiving data for each light emission amount stored in 5 with the light receiving pattern in the first table 31 (step S4).

The gain control unit 29 includes a pattern determination unit 32
By reading any one of the patterns A1 to A5 selected in the above, the gain setting values B1 to B corresponding to the selected pattern are read.
5 is selected from the second table 33 (step S5).
Then, the gain control section 29 controls the gain switching circuit 30 based on the selected gain setting value to set the gain of the amplifier circuit 23 (step S6). After the gain setting, the light emission amount steady setting unit 34 sets the light emission amount of the light emitting element 10 to a value for normal monitoring (step S7), and returns to the monitoring state.

Specifically, the gain of the amplifier circuit 23 is minimized (B
1), and sequentially adjusts the light amount of the light emitting element 1 to a light amount step (S1).
The case where the light receiving pattern A3 is selected in the collation of the first table 31 when the control is performed according to (5) will be described. That is, when the gain of the amplifier circuit 23 is minimized (B1), the light amount step S3 becomes an appropriate light emission level. Here, the light amount of the light emission level is returned to the normal monitoring light amount (light amount step S1), and the gain B3 of the amplifier circuit corresponding to the light receiving pattern A3 is selected from the second table 33, and the gain of the amplifier circuit 23 is set. At this time, the monitoring light amount (light amount step S1) emitted from the light emitting unit is received by the light receiving unit, and the output obtained through the amplifier circuit 23 set to the gain B3 becomes the reference level in the normal monitoring state. A warning is issued when the light receiving level is reduced by a predetermined amount or more with respect to the reference level. Further, the reference level is controlled to be constant even if the distance between the light emitting unit and the light receiving unit changes. For example, even when the distance between the light-emitting unit and the light-receiving unit is short and the light-receiving pattern A1 from which a proper output is obtained in the light amount step S5 is selected from the first table 31,
The light amount of the light emission level is changed to the normal monitoring light amount (light amount step S
1) and by selecting the gain B1 of the amplifier circuit, that is, the minimum gain from the second table 33, the amplifier circuit 2
The reference level obtained from 3 is constant.

Conversely, when the light emitting unit and the light receiving unit are far from each other, the first
If the light receiving pattern A5 is selected from the table 31 of
From the second table 32, the gain B5 of the amplifier circuit ,
As shown at the bottom of 4, the maximum gain is set to a fixed reference value from the amplifier circuit 23 is obtained.

As described above, when adjusting the reference level, the gain of the amplifier circuit 23 is minimized and the light emission amount on the light emitting section 1 side is sequentially changed, so that electrical noise on the amplifier circuit 23 side is largely prevented. be able to. This is because when the gain of the amplifying circuit 23 of the light receiving unit 2 is sequentially controlled with the light emitting output of the light emitting unit 1 kept constant, noise generated at the time of gain switching becomes more susceptible. Target noise can be largely prevented. Thus, the automatic gain setting of the amplifier circuit 23 is completed. The fine adjustment after the automatic adjustment may be performed separately.

In a normal monitoring state, the fire determining unit 26
A fire is determined by comparing the received light data stored in the received light data storage unit 25 with a preset threshold value. For example, assuming that the level of the received light data in a state where there is no fire is 100, if the threshold value is set to a dimming rate of 60%,
When the level of the received light data falls below 40, it is determined that a fire has occurred.

FIG. 5 shows an embodiment in which the present invention is applied to an integrated light beam type smoke detector. In this embodiment, since the light emitting element 10 is integrated, the receiving circuit 12 and the light emission control unit 21 shown in FIG. 1 are not provided.
The rest of the configuration is exactly the same as the previous embodiment. Also in this embodiment, the gain of the amplifier circuit 23 is adjusted by the same control procedure as described above.

In the above embodiment, the first table 31
And the second table 33 is used, but the gain may be calculated by calculation.

[0019]

As described above, according to the present invention, the light emission output of the light emitting section is sequentially controlled while the gain of the amplifier circuit of the light receiving section is kept constant, and the light output is set to a value within a predetermined range. Since setting means for setting the gain of the amplifier circuit of the light receiving unit based on a conversion table of the data and the gain of the amplifier circuit predetermined from the data at the time when the There is no need to adjust the volume by manipulating the volume, and the gain of the amplifier circuit of the light receiving section can be adjusted automatically and once. As a result, the adjustment time can be shortened, the gain can be accurately adjusted without being affected by noise, and unnecessary adjustment components can be reduced to reduce the cost. In addition, when the reference level is adjusted, the gain of the amplifier circuit is minimized and the light emission amount on the light emitting unit side is sequentially changed, so that there is an effect that electrical noise of the amplifier circuit can be prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a light beam type smoke detector according to the present invention.

FIG. 2 is a flowchart showing control of gain adjustment of an amplifier circuit of the light beam smoke detector according to the embodiment.

FIG. 3 is a diagram showing contents of a first table used in the embodiment.

FIG. 4 is a diagram showing contents of a second table used in the embodiment.

FIG. 5 is a block diagram showing a configuration of another embodiment of the light beam type smoke detector of the present invention.

6 (A) and 6 (B) are schematic diagrams showing the structures of a conventional separated type and an integrated beam type smoke detector, respectively.

FIG. 7 is a diagram showing an amplifier circuit gain adjuster provided in a conventional light beam smoke detector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light-emitting part 2 Light-receiving part 10 Light-emitting element 22 Light-receiving element 23 Amplifying circuit 25 Light-receiving data storage part 26 Fire determination part 27 Light emission amount control part 28 Gain minimum setting part 29 Gain control part 30 Gain switching circuit 31 First table 32 Pattern determination part 33 Second table

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Shuzo Minowa 2-10-43, Kami-Osaki, Shinagawa-ku, Tokyo Inside Hochiki Co., Ltd. (56) References JP-A-2-281395 (JP, A) JP-A Heisei 1-278120 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G08B 17/02-17/12 H03K 17/78

Claims (1)

(57) [Claims] 1. A monitoring light emission output emitted from a light emitting unit.
In the light beam type smoke detector which receives the light beam at the light receiving portion and detects a fire by a change in the light receiving output due to the invasion of smoke, the light emitting output of the light emitting portion is provided with the gain of the amplifier circuit of the light receiving portion being fixed. Are sequentially controlled, and the data obtained when the received light output becomes a value within a predetermined range is determined in advance from the data.
A light-type smoke detector comprising: setting means for setting a gain of the amplifier circuit of the light receiving unit based on a conversion table between data and a gain of the amplifier circuit.