JPH07296276A - Photoelectric fire sensor - Google Patents

Abstract

PURPOSE:To unnecessitate the installation of a calculation formula table and reference table for each fire sensor by reading the light reduction rate corresponding to the light reception output as a signal showing the physical amount of smoke from a storage means. CONSTITUTION:When there is no reception signal from a fire receiver 18 and there is a timer interrupt, the light emitting command is outputted for a light emitting element 10. The light receiving output SLVx of a light receiving element 11 is temporarily read in a RAM 6. The light reduction rate Dx corresponding to the light receiving output SLVx is read out from the reference table stored in a storage area 52 of a ROM 5. The light reduction rate Dx is updated and stored in a prescribed area of the RAM 6, then the operation above-mentioned is repeated. On the other hand, when a reception signal comes and if it is the self address being a call signal from the fire receiver 18 and the state information request command, the light reduction rate Dx is read out from the RAM 6 and it is sent to the fire receiver 18. Thus, detected physical amount of smoke is converted into the light reduction rate Dx at the transmission. The fire discrimination can be performed by comparing the light reduction rate Dx with the fire discrimination level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric fire detector, and more particularly to an analog type photoelectric fire detector that detects a physical quantity of smoke and outputs a physical quantity signal.

[0002]

2. Description of the Related Art Usually, an analog photoelectric fire detector sends out the detected analog (physical quantity) level of smoke to a receiving part such as a fire receiver or a repeater. For example, the presence or absence of a fire is discriminated by comparing it with the fire discrimination level. By the way, the sensitivity adjustment of the analog photoelectric fire detector is
The scattered light type fire detector detects smoke according to the scattered light principle, while it is performed based on the extinction ratio (% / m).

For this reason, the relationship between the received light output of the smoke detector and the extinction ratio generally shows a linear characteristic at a low smoke concentration.
As the smoke density increases, it exhibits a non-linear characteristic. And this characteristic is that if the shape of the optical chamber (dark box) for detecting smoke, the light emitting element, and the light receiving element are the same,
Although they have almost the same characteristics, different characteristics, that is, the degree of curvature increases or decreases depending on the shape of the optical chamber, the type of the light emitting element, or the model of the light receiving element.

In the conventional analog photoelectric fire detector, the received light output corresponding to the physical quantity of smoke detected by the smoke detector is converted into the extinction ratio and sent to the receiver. This is because the sensitivity of the photoelectric fire detector is defined by the extinction rate. The conversion from the received light output to the extinction ratio is performed by proportional calculation, which will be described with reference to FIG. In FIG. 4, a solid line Y1 is a characteristic showing the relationship between the actual received light output and the extinction ratio. Dimming rate 0% / m,
That is, the received light output SLV1 of the smoke detector of the fire detector when there is no smoke is measured, and the received light output SLV when the fire detector is placed in a dark box with a smoke density of D1 (% / m)
Measure 2. A characteristic Y2 is obtained by connecting the points corresponding to both the measured light reception outputs as shown by the dotted line in FIG. This characteristic Y2 is expressed by the following equation.

Y2 = {(SLV2-SLV1) / D1} × Dx + SLV1 (1)

From the equation (1), the following equations (2) and (3) are obtained. SLVx = {(SLV2-SLV1) / D1} * Dx + SLV1 (2) Dx = D1 * (SLVx-SLV1) / (SLV2-SLV1) (3)

However, in the above equations (2) and (3), SLVx is the light reception output when the smoke density is the extinction rate Dx (% / m). Therefore, if the received light output SLVx is obtained from the smoke detector, Dx indicating the smoke density at that time is obtained from the equation (2) or the equation (3). Then, the fire detector converts the smoke density Dx as a detected physical quantity signal of smoke into a digital signal when it is called by the receiving unit by polling or the like, and sends it out.

As can be seen from FIG. 4, the characteristic Y1 is a non-linear characteristic, while the characteristic Y2 is a linear characteristic. Therefore, the smoke density Dx obtained by the calculation by the formula (2) or the formula (3) is a value that substantially coincides with the characteristic Y1 while the smoke density is low, but the smoke density Dx deviates from the characteristic Y1 as the smoke density increases. Deserves. That is, in FIG. 4, when the received light output SLV2 is obtained, the smoke density Dx corresponding to this is calculated as D1 from the equation (3), and the calculated smoke density, that is, the extinction ratio D1 is sent to the receiving unit. . The calculated extinction ratio D1 matches the characteristic Y1.
On the other hand, when the received light output SLV3 is obtained, the smoke density Dx corresponding to this is calculated from the formula (3) as the extinction ratio D3, and this is sent to the receiving unit.

By the way, the actual smoke density for the received light output SLV3 is the extinction ratio D2, as is clear from the characteristic Y1 in FIG. Therefore, the smoke density (light extinction rate) D3 calculated by the equation (3) is higher than the actual smoke density (light extinction rate) D2, as shown in FIG. In order to prevent this, as shown in FIG. 4, instead of obtaining the characteristic Y2 at two points, the light reception output SLV and the extinction ratio D are obtained at a plurality of three or more points, and the calculation is performed by subdividing. Conceivable. However, in this case, it is necessary to obtain the received light output SLV and the extinction ratio D at a plurality of three or more points by making the smoke concentration different for each fire detector, which is troublesome and requires a plurality of points. It is difficult to align the same extinction ratio D at three or more points among the fire detectors, and there is a problem that the fire detectors vary.

Therefore, as described above, there is almost no difference in the characteristic Y1 in FIG. 4 between the shape of the optical chamber and the fire detectors of the same model using the same type of light emitting element and light receiving element. Paying attention to the fact that there is not, the received light output SLV1 for the smoke density D0 (smoke density 0) of each fire detector and the received light output SLV2 for the smoke density D2 (or smoke density D3
The received light output SLV3) is adjusted so that each of the fire detectors sends out the received light output SLVx to the receiving unit, and the receiving unit subdivides the characteristic Y1 to calculate the smoke density Dx from the received light output SLVx. It is conceivable to provide a calculation means and calculate and obtain the smoke density Dx for the received light output SLVx sent from each fire detector by this calculation means. Similarly, between fire detectors of the same model,
Paying attention to the fact that there is almost no difference in the characteristic Y1 in FIG. 4, a comparison table of smoke density D with respect to the received light output SLV is provided in the reception unit, and the received light output S from each fire detector is provided.
When LVx is received, received light output S from the reference table
It is conceivable to obtain the smoke density Dx corresponding to LVx.

[0011]

However, in the case of the conventional method as described above, it suffices that the same type of photoelectric fire detector is connected to the fire receiver, the repeater, etc. Different types of photoelectric fire detectors, such as when an additional fire detector is added due to an extension or renovation in the building, or when the photoelectric fire detector is improved. When mixed and connected,
As described above, the characteristics Y1 are different between different models when the shape of the optical chamber and the light emitting element and the light receiving element are different. Therefore, the calculation formula suitable for the model of the fire detector newly connected to the receiving unit. Alternatively, a reference table must be added, and a determination means for determining which type of fire detector receives the light reception output must be provided, which is very troublesome and the determination means If the model setting of each fire detector is wrong, there is a problem that a so-called false alarm is generated to judge that a fire is not a fire, or a so-called false alarm is not generated that a fire is judged to be a fire.

The present invention has been made to solve such a problem, and it eliminates the need for a formula for calculating the extinction ratio from the signal received by the receiver and a work for incorporating a reference table and a setting work. Another object of the present invention is to obtain a photoelectric fire detector capable of preventing false alarms and false alarms, improving reliability, and being compatible with each other even if the fire detector models are different.

[0013]

A photoelectric fire detector according to the present invention sends a signal indicating a physical quantity of smoke detected by a scattered light type smoke detector having a light emitting element and a light receiving element to a receiving section. In the analog photoelectric fire detector, the storage means that stores the comparison table regarding the extinction ratio with respect to the received light output of the smoke detector, and the received light output corresponding to the received light output when the smoke detector receives the received light output. The reading means is provided for reading the light rate from the storage means as a signal indicating the physical quantity of smoke.

[0014]

In the present invention, since the detected physical quantity of smoke is converted into the extinction ratio and then sent out, the receiving unit which collects the extinction ratio from each fire detector by polling or the like uses the received extinction ratio, for example. Fire discrimination can be performed by comparing with the fire discrimination level. This eliminates the need to provide a formula for calculating the extinction ratio from the signal received by the receiving unit and a reference table for each model of fire detector, eliminating the need for assembling work and setting work, resulting in false alarms and loss. Information can be prevented. Even if the model of the fire detector is different, since the fire detector of each model sends out the physical quantity of smoke at the dimming rate, compatibility can be obtained between the fire detectors.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 1 is an analog photoelectric fire detector (hereinafter, simply referred to as a fire detector), 2 is a microprocessor unit (hereinafter, referred to as MPU) as arithmetic means for performing various arithmetic processes described later, and 3 and A data bus 4 and a control bus 4 are connected to the MPU 2, respectively.

Reference numeral 5 is a read-only memory (hereinafter referred to as ROM) as a storage means connected to the MPU 2 via the data bus 3 and the control bus 4, and the ROM 5 has a flow chart shown in FIG. A storage area 51 in which related programs, common addresses, own addresses, types, various constants, etc. are stored in advance,
For example, it includes a storage area 52 in which a comparison table of received light output vs. extinction ratio as shown in FIG. 2 is stored in advance.

Reference numeral 6 denotes a random access memory (hereinafter referred to as RAM) as a storage means connected to the MPU 2 via the data bus 3 and the control bus 4.
The RAM 6 is used to update and store a work area used when the MPU 2 performs arithmetic processing, and the latest multiple times of fire phenomenon detection output (light reception output) (for example, three consecutive times every three seconds). And a storage area. 7 is the data bus 3
Also, the timer is connected to the MPU 2 via the control bus 4 and generates a timer interrupt for performing a smoke detection operation at a predetermined time interval of, for example, every 3 seconds.

Reference numeral 9 is an interface (hereinafter referred to as IF)
8, via data bus 3 and control bus 4 to M
A light emission control circuit which is connected to the PU2 and controls a smoke detection light emitting element which will be described later, 10 is a light emitting element such as a light emitting diode which is connected to the light emission control circuit 9, and 11 is a smoke of light emitted from the light emitting element 10. A photodiode that receives scattered light, a light receiving element including a solar cell, and 12 is an amplifier circuit that amplifies a light receiving output of the light receiving element 11.

Reference numeral 13 denotes a sample hold circuit which is connected to the amplifier circuit 12 and samples the light reception output amplified by the amplifier circuit 12 and holds it until the next light emission. Reference numeral 14 is connected to the sample hold circuit 13 and An A / D conversion circuit for converting an output from an analog signal to a digital signal, 15 is an M / D conversion circuit for outputting the output side of the A / D conversion circuit 14,
This is an IF connected to PU2. The sample hold circuit 13 and the A / D conversion circuit 14 are controlled by the CPU 2 via the IF 15.

Reference numeral 17 is connected to the MPU 2 via the IF 16, the data bus 3 and the control bus 4, and a parallel-serial conversion circuit, a transmission circuit, a reception circuit and a direct circuit (not shown) for transmitting / receiving information to / from an adjusting device described later. A transmission / reception circuit including a parallel conversion circuit and the like. When the transmission / reception circuit 17 is also connected to the fire receiver 18 or the like, it transmits / receives information to / from the fire receiver 18 or the like. Reference numeral 19 is another photoelectric fire detector.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG. In addition, all determinations in the following description of the operation are performed by the MPU 2. In step S1, the RAM 6, IFs 8, 15, 16 and the like are initialized, and in step S2, it is determined whether or not there is a received signal from the fire receiver 18, and if not, in step S3, a timer interrupt by the timer 7 is performed. If there is a timer interrupt, wait for a reception signal or a timer interrupt. If there is a timer interrupt, a light emission command is issued to the light emitting element 10 via the IF 8 and the light emission control circuit 9 in step S4. Output.

Then, in step S5, the light reception output SLVx of the light receiving element 11 at this time is temporarily read into the RAM 6 via the sample hold circuit 13, the A / D conversion circuit 14 and the IF 15, and in step S6, RO
The extinction rate Dx corresponding to the received light output SLVx is read from the contrast table (FIG. 2) stored in the storage area 52 of M5, and the read extinction rate Dx is updated to a predetermined area of the RAM 6 in step S7. After storing, the process returns to step S2 to repeat the above operation.

On the other hand, if there is a received signal at step S2,
In step S8, it is determined whether the received signal is a self-address which is a calling signal from the fire receiver 18,
If it is a self address, it is determined in step S9 whether it is a status information request command. If it is a status information request command, in step S10, the dimming rate Dx is read from the RAM 6 and sent to the fire receiver 18. After performing the processing such as the above, the process returns to step S2 and the above-described operation is repeated. If it is not the self address in step S8, or if it is not the state information request command in step S9,
In both cases, the process returns to step S2 and the above-described operation is repeated.

As described above, in this embodiment, when converting the analog level of the detected value of the received light output, by using the preset linearization table, that is, the reference table, the smoke concentration (% / m) vs. the analog level straight line Can be realized.

In the above embodiment, the case where the received light output SLVx is read once at the time of level conversion has been described, but it is read a plurality of times and the respective average values are read.
The average value of each deviation or the intermediate value of each deviation may be stored in the RAM.
By doing so, even if the received light output is temporarily affected by induced noise during level conversion, that effect can be eliminated.

[0026]

As described above, according to the present invention, an analog photoelectric sensor for sending a signal indicating a physical quantity of smoke detected by a scattered light type smoke detecting section having a light emitting element and a light receiving element to a receiving section. In the fire detector, the storage means that stores a comparison table regarding the extinction ratio with respect to the received light output of the smoke detection unit, and when the received light output is obtained from the smoke detection unit, the extinction ratio corresponding to this received light output is smoked. Since there is a reading means for reading out from the storage means as a signal indicating the physical quantity of, it is not necessary to provide a calculation formula or a reference table for calculating the extinction ratio from the signal received by the receiving unit for each model of fire detector. , These built-in work and setting work are unnecessary, and false alarms and false alarms can be prevented to improve reliability, and even if the fire detector model is different, the fire detector of each model will , Smoke Since delivering amounts extinction ratio there is an effect that compatibility between fire detector mutual is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a comparison table used in an embodiment of the present invention.

3 is a flowchart for explaining the operation of FIG.

FIG. 4 is a diagram for explaining the relationship between the received light output and smoke density in a conventional fire detector.

[Explanation of symbols]

 1 Photoelectric Fire Detector 2 Microprocessor Unit (MPU) 5 Read Only Memory (ROM) 6 Random Access Memory (RAM) 7 Timer 9 Light Emission Control Circuit 10 Light Emitting Element 11 Light Receiving Element 13 Sample Hold Circuit 14 A / D Conversion Circuit 17 Transceiver circuit

Claims (1)

[Claims] 1. An analog photoelectric fire detector for sending a signal indicating a physical quantity of smoke detected by a scattered light type smoke detecting section having a light emitting element and a light receiving element to a receiving section, wherein the smoke detecting section Storage means for storing a comparison table regarding the extinction ratio with respect to the received light output, and when the received light output is obtained from the smoke detection section, the extinction ratio corresponding to the received light output is used as a signal indicating the physical quantity of smoke. A photoelectric fire detector, comprising: a reading means for reading from.