JPH0480896A - Sensor - Google Patents

Abstract

PURPOSE:To save labor for check and to prevent an object from being erroneously recognized as out of standard even when it is within the standard by directly inputting the judging output of a comparator circuit part to a switching circuit when a check switch is set in a check state. CONSTITUTION:Between an input part (a) of an accumulation circuit part 16 and the gate of a thyristor 17, a field effect transistor FET is inserted as a switching element to directly input the output of a comparator circuit part 15 to the gate of the thyristor 17 as the switching circuit when a check switch SW2 is set in the check state, namely, is closed. Therefore, when the check switch SW2 is set in the check state, the switching circuit 17 can be operated by the output of the comparator circuit part 15 and in the case of normal use, the switching circuit 17 can be operated by an output from the accumulation circuit part 16. Thus, labor for check can be saved, and the object can be prevented from being erroneously recognized as out of the standard although it is within the standard.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sensor having an accumulation processing function, such as a smoke detector.

[Conventional technology]

FIG. 6 is a diagram showing the principle of a photoelectric smoke detector l corresponding to the sensor. The light-emitting element 11 and the light-receiving element 12 are arranged in an optical room covered with a light-shielding wall 13 that prevents outside light from entering but allows smoke to flow in and out. The axis and the light-receiving axis of the light-receiving region R of the light-receiving element 12 are arranged to intersect, and the light from the light-emitting element 11 does not enter the light-receiving element 12 directly. The area where the light emitting area U and the light receiving area R intersect is called a smoke detection area T. Furthermore, the inner surface of the optical chamber surrounding the light emitting element 11, light receiving element 12, and smoke detection area T is painted black to prevent the light from the light emitting element 11 from being diffusely reflected by the inner surface of the optical chamber and being received by the light receiving element 12. are doing.

Here, when smoke enters the smoke detection area T through the gap in the light shielding wall 13, the light from the light emitting element 11 hits the smoke particles and is scattered. This scattered light is received by the light receiving element 12 and detected as an electrical signal according to the amount of scattered light. Since the amount of scattered light increases as the smoke density increases, the smoke density can be detected based on the level of the electrical signal from the light receiving element 12.

The above is the principle of the photoelectric smoke detector 1.

By the way, in the above explanation of the principle of the photoelectric smoke detector 1, it was mentioned that the inner surface of the optical chamber is painted black to prevent the light from the light emitting element 11 from being diffusely reflected by the inner surface and being received by the light receiving element 12. However, this cannot be completely prevented and the diffusely reflected light from this inner surface enters the light receiving element 12, but the amount of light is called the noise component N, and the amount of scattered light that hits the smoke particles entering the light receiving element 12 will be called signal component S.

The photoelectric smoke detector 1 detects smoke density using the amount of rudder light received as a sensor that enters the light receiving element 12, and is configured to issue an alarm when the amount of rudder received light X exceeds a predetermined darkness value light amount X0. ing. Therefore, the rechargeable smoke detector 1 has a signal component S
It can be said that it is determined whether the total value of the noise component N exceeds the darkness value light amount X0.

In other words, it is determined whether X≧X0 based on X=S1N. Note that the noise component N
varies depending on the amount of light emitted from the light emitting element 11, but if the amount of light emitted is constant, the noise component N is approximately constant.

By the way, if such a sensor immediately issues an alarm just because the detected amount temporarily exceeds a predetermined detected amount, there is a risk of erroneous recognition. For example, in the case of the photoelectric smoke detector 1, when smoke from a fire should have been detected and an alarm issued, an air mass of cigarette smoke happens to pass through the photoelectric smoke detector 1, resulting in - In some cases, the detected amount exceeds a predetermined detection level and the photoelectric smoke detector 1 issues an alarm (such an alarm is called a false alarm). In order to prevent such false alarms, there is a function that issues an alarm only when a predetermined sensing amount has been exceeded continuously for a predetermined period of time (this is an accumulation processing function, a circuit that performs this processing is an accumulation circuit, and a circuit that performs this processing is There are sensors equipped with a

FIG. 5 is a circuit block diagram of the main parts of the photoelectric smoke detector 1, and normally there are two signal line connection terminals connected to the signal line from a disaster prevention receiver (not shown) and supplied with power. have. A thyristor 17 as a switching circuit and a constant voltage generation IT source 1 are connected between the signal line connection terminal and 0.
9 are connected in parallel.

The output of the constant voltage generator 1619 includes the light emitting element 11 (which emits light with current and the amount of light emitted increases or decreases depending on the magnitude of the current) and the light emitting element 11
Light emitting t! A series circuit of the control circuit 21, a drive circuit section 20 that supplies a switching pressure to the base of a transistor Tr as a switching element in the light emitting current control circuit 21, and an accumulation circuit section 16 that accumulates and processes input from the input section a, respectively. connected in parallel. Further, the output section of the storage circuit section 16 is connected to the gate of the thyristor 17.

The detection unit 14, which includes a light receiving element 12 through which a current changes depending on the amount of light received by the rudder X as a sensing amount, and an amplifier AP that converts this current into a voltage and amplifies it, detects a voltage according to the amount of light received by the rudder X. This output is connected to a comparison circuit section 15 including a comparator CP. The output of the comparison circuit section 15 is connected to the input section a of the storage circuit section 16. Further, the light emitting current control port WI21 is configured by connecting a series circuit of a resistor R1, a check switch SW2, and a resistor R2 in parallel, and connecting one end of each circuit to the collector of the transistor Tr. The inspection switch SW2 is a switch for inspecting the detection sensitivity of the photoelectric smoke detector l.

From the drive circuit section 20 to the base of the transistor Tr,
Turn on the transistor Tr for about 100tts at a cycle of about 3 seconds.
A pulse signal is input, and the light emitting element 11 emits light in synchronization with the pulse signal. Further, the light emitting element 11 has a characteristic that the amount of light emitted increases or decreases depending on the magnitude of the current flowing through the light emitting element 11. Photoelectric smoke detector 1 has normal inspection switch S
It is used with Wz open, and in this case, the amount of light emitted by the light emitting element 11 is small, and the amount of light emitted by the light emitting element 11 is determined by the resistor R1.

The resistor R3 is a semi-fixed resistor, and this value is determined when the photoelectric smoke detector 1 is placed in a closed test chamber at a predetermined alarm smoke concentration Q according to the product standard (at this time, the light receiving element 12 If the amount of light received by the rudder X is XM and the side component S is S, then
, =SII +N Null equation is established) and placed in a test tank with a predetermined non-alarm smoke concentration QL (at this time, the amount of rudder light received by the light receiving element 12 is XL, and the signal component S is SL). Then, X t ”' S L + N
(The following formula holds true) Fine adjustment is made so that the alarm does not occur. In this way, if the smoke density becomes a predetermined smoke density Q or more (assuming that the amount of rudder light received by the light receiving element 12 at this time is xo and the signal component S is So, the formula X@ = so + N holds true). This makes it possible to create a photoelectric smoke detector l that complies with the standards for issuing alarms (provided that Q, ≧Qo≧Q.

, XM≧x0≧XL, and 50≧S on SN).

However, when the photoelectric smoke detector 1 is used in the field, its characteristics may change over time (a decrease in the amount of light due to dirt on the light emitting element 11 or a decrease in the amount of received light due to dirt on the light receiving element 12). There are some that are out of specification. Therefore, the characteristics of photoelectric smoke detectors are regularly tested using the inspection function in the field.

This inspection function is configured as follows.

When there is no smoke, the amount of rudder light received by the light receiving element 12 becomes equal to the noise component N. However, since the amount of light emitted from the light emitting element 11 increases when the current flowing through the light emitting element 11 increases, by appropriately determining the value of the resistor R2, when the check switch S W z is turned on, the light emitting element 11
Normal current I flows through resistor R8, and current 1. flows through resistor R2. , and the amount of noise component N entering the light receiving element 12 at this time can be increased. Then, the amount of the noise component N at this time is expressed as N [11,12], and the value of the resistor R1 is appropriately adjusted so that it becomes substantially equal to the received light amounts X and I. In other words, N [1+, I2] ', X x . Therefore, when the inspection switch SW2 is turned on, the photoelectric smoke detector 1 should alarm, and if it does not, the characteristics of the photoelectric smoke detector 1 will change, and if the smoke density is not higher than the standard, it will alarm. If it does not, it will be out of specification.

Further, if the amount of noise component N when the normal current 11 flows through the light emitting element 11 is expressed as N[+11, the following equation holds true.

N [1+] < N [L, Iz1 Next, the operation of the photoelectric smoke detector 1 will be explained with reference to FIGS. 4 and 5.

A drive circuit section 20 in the photoelectric smoke detector 1 that is connected to a signal line from a disaster prevention receiver and receives power supply includes a transistor T.
A pulse signal that turns on r for about 100 μs at a cycle of about 3 seconds is output to the base of the transistor Tr, and the light emitting element 11
emits light in synchronization with the light emitting element 11.The amount of light emitted by the light emitting element 11 is determined by the current flowing through the light emitting element 11.During normal use, the check switch SW2 is open, so the light emitting element 11
The current flowing through is only current 1 determined by resistor R8.

Assuming that there is no smoke now, the amount of rudder light received by the light receiving element 12 becomes N [II]. Therefore, the detection section 14 outputs an output voltage corresponding to the detected amount, that is, the amount of received light N[1,] to the comparison circuit section 15. Here, N[I+]<xL≦X
Since it is 0, the comparison circuit section 15 outputs a judgment output of non-alarming to the accumulation circuit section 16. That is, in the timing chart of the input section a and the output section of the storage circuit section 16 shown in FIG. 4, the state of the input section a becomes a Low state. Therefore, the storage circuit section 16 does not start storage, and the output section of the storage circuit section 16 continues in the Lo11 state, keeping the thyristor 17 in a non-conductive state. Therefore, the photoelectric smoke detector l does not issue an alarm.

Next, it is assumed that smoke enters the smoke detection area T of the photoelectric smoke detector 1, light scattered by smoke particles increases, and the amount of rudder light received entering the light receiving element 12 exceeds the darkness value light amount x0. Then, the comparator circuit section 15 outputs an alarm determination output to the accumulation circuit section 16. That is, in the timing chart of the input section a and the output section of the storage circuit section 16 shown in FIG. 4, the state of the input section a becomes the old GH state. Therefore, the accumulation circuit section 16 starts accumulation, and only when the state of the input section a continues to be in the old gh state for more than a predetermined accumulation time t (generally about 10 seconds), the output section of the accumulation circuit section 16 starts to accumulate. becomes the old gh state and makes the thyristor 17 conductive. Then, thyristor 17
A conductive current is passed between the signal line connection terminal C and C, and the photoelectric smoke detector 1 issues an alarm.

A disaster prevention receiver (not shown) that detects this continuity notifies the administrator through an alarm sound and a display device.

Next, a method of testing the characteristics of the photoelectric smoke detector 1 using the above-mentioned inspection function will be explained. Normally, the inspection switch SW2 is a reed switch whose contacts open and close depending on the presence or absence of a magnetic field.
Here, a type of reed switch is used in which a contact opens in the absence of a magnetic field and closes in the presence of a magnetic field.

Therefore, in a smoke-free state, a test rod with a magnet at the tip is brought close to the outer surface of the photoelectric smoke detector 1 on the side where the inspection switch SW2 is located, and the inspection switch SW2 is closed. Then, the current flowing through the light emitting element 11 becomes the sum of the current 1 flowing through the resistor R3 and the current I2 flowing through the resistor R2, and the amount of light emitted increases, and the light receiving element 12 receives the amount of light N[L, Izl. Then, the aforementioned smoke density increases, the amount of light scattered by the smoke particles increases, and the amount of rudder light received entering the light receiving element 12 becomes the darkness value light amount
The photoelectric smoke detector 1 should issue an alarm in the same way as when the value exceeds 0, and if it does not, the photoelectric smoke detector 1
This means that the characteristics change and the smoke density exceeds the standard in that it will not issue an alarm unless the smoke density is higher than the standard. In this way, photoelectric smoke detectors 1 that are inspected on-site and found to be out of specification are repaired, replaced, etc., and the site is always maintained with only photoelectric smoke detectors 1 that are within the standards. Safety is maintained.

[Problem to be solved by the invention] In order to check the deterioration of characteristics over time of a sensor having an accumulation processing function and a detection sensitivity check switch in the field, when the check switch is set to the check state, the accumulation time t is Unless the time has elapsed, the photoelectric smoke detector 1 will not issue an alarm. Therefore, it is not immediately clear whether the sensor is within the standard or not. Therefore, there is a problem in that inspection is time-consuming and, in some cases, the sensor is mistakenly recognized as being outside the standard even though it is within the standard because the alarm is not issued immediately.

The present invention was made in order to improve the above problems, and its purpose is to reduce the time and effort required for inspection.
Moreover, it is an object of the present invention to provide a sensor having an accumulation processing function and a detection sensitivity check switch, which does not erroneously recognize that something is out of the standard even though it is within the standard.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention includes a detection section that outputs a sensing output according to the amount of sensing, a comparison circuit section that outputs an output when the sensing output from the detection section is equal to or higher than a predetermined level, and In a sensor having an accumulation circuit section that outputs an output when the output from the comparison circuit section continues for a predetermined time or more, a switching circuit that outputs an alarm signal based on the output from the accumulation circuit section, and a detection sensitivity check switch. , when the inspection switch is in the inspection state, the determination output of the comparison circuit section is directly input to the switching circuit.

[Effect]

With the above configuration, when the inspection switch of the sensor is in the inspection state, the switching circuit can be operated by the output of the comparison circuit section, and during normal use, the switching circuit can be operated by the output from the storage circuit section. It is.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained based on FIG. 1, and another embodiment will be explained based on FIG. 2.

FIG. 1 is a circuit block diagram of a main part of a photoelectric smoke detector 1 corresponding to a sensor according to the present invention, and is different from the conventional example in the following points.

When the inspection switch SW2 is in the inspection state, that is, it is closed, the field effect transistor PET as a switching element that inputs the output of the comparison circuit section 15 directly to the gate of the thyristor 17 as a switching circuit is connected to the input of the storage circuit section 16. This is because it is inserted between part a and the gate of thyristor 17. In addition, a diode D for preventing backflow is inserted between the output section of the storage circuit section 16 and the gate of the thyristor 17, and the light emitting IT flow control circuit 21 of FIG.
The value of the resistor R1 is appropriately divided into two resistors R2° and R2, and the voltage across the resistor R2° is inputted as a switching signal to the field effect transistor FET.

Therefore, the photoelectric smoke detector 1, which is connected to the signal line from the disaster prevention receiver (not shown) and receives the power supply from the signal line connection terminal C, is connected to the inspection switch, which is a reed switch, during normal use. Since SW2 is open, there is no switching signal input to the field effect transistor FET, so the field effect transistor FET is in a cutoff state. Therefore, the thyristor 17 in the storage circuit section 16 operates with the output from the output section of the storage circuit section 16 which has undergone the storage process as described in the conventional example. In other words, during normal use, it has an accumulation processing function.

Next, in order to check the detection sensitivity of the photoelectric smoke detector 1, in the absence of smoke, use a test rod with a magnet at the tip.
7 When approaching S W z, the inspection switch SW2 closes, and the sum of the current ■1 flowing through the resistor R3 and the current I2 flowing through the inspection switch SW2 flows to the light emitting element 11, the amount of light emitted by the light emitting element 11 increases, and the light receiving element The rudder light reception amount X of No. 12 is N[I
l, I2].

By the way, since N [1+, Izl', X□ ≧X0,
The comparator circuit section 15 outputs an alarm determination output to the input section a of the storage circuit section 16. In other words, the input section a of the storage circuit section 16
Set to H4gh. Then, the storage circuit section 16 starts the storage process. However, at the same time as the inspection switch S W z is closed, the current 2 flows through the resistor R2 and provides a switching signal input to the field effect transistor FET (since the gate current of the field effect transistor FET is approximately zero, the current flowing through the light emitting element 11 has no effect). Therefore,
The field effect transistor FET becomes conductive, and the alarm output of the comparator circuit section 15 is directly input to the gate of the thyristor 17.

Therefore, the output of the comparison circuit section 15 is the alarm judgment output High.
Since the thyristor 17 becomes conductive at the same time as the signal h is output, that is, at the same time as the accumulation processing of the accumulation circuit section 16 is started, the photoelectric smoke detector 1 issues an alarm without waiting for the accumulation time. In other words, the inspection result of the sensing sensitivity becomes known at the same time as the inspection switch SW2 is closed. Also, the storage function operates during normal use.

Next, another embodiment will be described based on FIG. 2. FIG. 2 is a circuit block diagram of a main part of a photoelectric smoke detector 1 corresponding to the sensor according to the present invention, and differs from FIG. 1 in the following points.

The field effect transistor PET shown in FIG. 1 is replaced by a check switch SW2. Inspection switch S
W2 is a reed switch having two interlocking contacts S O1 + S ox , and contact S. I has the same function as the inspection switch SW2 of the light emission control circuit 21 shown in FIG.
The contact set has the same function as the field effect transistor PET shown in FIG. In Figure 2, a field effect transistor FET is not used, but a contact set is used, so
Since there is no need to apply a gate input signal to the field effect transistor FET, there is no need to divide the resistor R2 in FIG. 5 into the resistor R2° and the resistor R21 as in FIG. 1. Therefore, the resistor R2 in FIG. 5 and the resistor R2 in FIG. 2 have the same resistance value.

Also, in the case of Fig. 2, both contacts SOI+ S01 of inspection switch SW2 are open during normal use.
When inspecting the sensing sensitivity, a magnet is brought close to the inspection switch SW2, and both contacts SO1+SOX of the inspection switch SW2, which is a reed switch, are closed.

Therefore, as in the embodiment shown in FIG. Therefore, the comparison circuit section 15 outputs the alarm judgment output old gh without waiting for the accumulation time t, and at the same time the thyristor 17 becomes conductive, and the photoelectric smoke detector 1 We will issue a report. In other words, the inspection result of the sensing sensitivity becomes clear at the same time that both contacts "01+ soz" of the inspection switch SW2 are closed.

In this embodiment, the present invention is explained using a photoelectric smoke detector, but the present invention is not limited to a photoelectric smoke detector, and has an accumulation processing function and a detection sensitivity check switch. Needless to say, it is effective for all sensors that have the same function.

〔Effect of the invention〕

Since the sensor of the present invention is configured as described above, the storage processing function is effective during normal use, and when checking the sensing sensitivity, the sensing sensitivity can be checked without waiting for the storage time. The results are immediately obvious. Therefore, the sensor is equipped with an accumulation processing function and a detection sensitivity check switch, which does not take much time to inspect and does not misidentify something as being outside the standard even though it is within the standard. It has the effect of being able to provide the following.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing one embodiment of the photoelectric smoke detector according to the present invention, Fig. 2 is a circuit diagram showing another embodiment, and Fig. 3 is the alarm threshold light reception amount of the photoelectric smoke detector. Figure 4 is a timing chart showing the input/output relationship of the storage circuit section, Part 5 is a circuit diagram of a conventional photoelectric smoke detector, and Figure 6 is a diagram of the operating principle of a photoelectric smoke detector. It is. 1-sensor, 14-detection section, 15-comparison circuit section storage circuit section, 17 switching circuit, Wz inspection switch.

Claims (1)

[Claims] (1) A detection section that outputs a sensing output according to the sensing amount, a comparison circuit section that outputs an output when the sensing output from the detection section is above a predetermined level, and an output from the comparison circuit section that continues for a predetermined period of time. In a sensor including an accumulation circuit section that outputs an output when the above continues, a switching circuit that outputs an alarm signal by the output from the accumulation circuit section, and a detection sensitivity inspection switch, when the inspection switch is in the inspection state, the A sensor characterized in that the judgment output of the comparison circuit section is directly input to the switching circuit.