JPH0632147B2 - Fire alarm system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fire alarm system in which a receiver and a smoke sensor have an intelligence function.

[Background technology]

In the conventional fire alarm system, when the sensor connected to the signal line is activated, the relay on the receiver side operates by the line current flowing in the line, and the bell and the indicator are connected by the output contact. It was working.

However, in the conventional system, since the operating state of each sensor cannot be constantly monitored, the failure cannot be recognized on the receiver side, which causes a serious trouble such as a false alarm.

[Object of the Invention]

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a smoke detector with the ability to monitor its own function stop, and to send the monitoring data to the receiver side together with the detected smoke density data. By sending out at the time of calling, the state of the smoke detector can be constantly monitored by the receiver side and high reliability can be maintained at all times, and even if the smoke detection unit deteriorates or becomes dirty, it will automatically It is to provide a fire alarm system that can be covered.

[Disclosure of Invention]

The present invention will be described below with reference to examples. FIG. 1 shows a basic schematic configuration diagram of an embodiment, in which an intelligence type smoke detector is connected to a signal line 1 derived from a receiver (1).
(2) and the general type smoke detector (3a) and heat detector (3b) are mixed and connected. The receiver (1) converts the transmission signal V _S, which is a pulse code signal including the address signal individually assigned to each intelligence type smoke detector (2), into the line voltage or current of the signal line 1 as shown in FIG. As shown in the figure, the information is sent in a cyclic sequence by superimposing it, and the information sent as a return signal from each called intelligence smoke sensor (2) is determined and the line voltage and line current of the signal line 1 are determined. General type smoke detector by monitoring the level (3a)
Alternatively, various control operations such as receiving the level signal V _L from the general type heat sensor (3b) can be performed.

The intelligent smoke sensor (2) can be set to an address separately, and the transmission signal V _S sent from the receiver (1)
When the address signal included in matches the own setting address, transmission signal V _S and receiver various information during return period that is provided between the next transmission signal V _S as a pulse code signal to the (1) It is supposed to be superposed and returned. When the general type smoke detector (3a) or heat detector (3b) detects a predetermined smoke concentration or temperature, it turns on and shorts the signal line 1 through an appropriate resistor to level the line current or line voltage. The fire detection signal is transmitted to the receiver (1) as the level signal V _L.

However, at any time, the receiver (1) calls each intelligence type smoke detector (2) in sequence and fetches information from each intelligence type smoke detector (2) and makes a determination, and the signal line l Monitor the operation of the general smoke detector (3a) or the heat detector (3b) by detecting the voltage or current level of the terminal, and further terminate the termination (4) such as the resistance of the signal line l.
By detecting a steady line voltage or line current due to, the circuit is monitored for a short circuit or disconnection of the signal line 1.

Next, specific configurations of the receiver (1) and the intelligence type smoke detector (2) will be described.

The receiver (1) has a basic unit (1A), as shown in FIG.
Extension unit (1B) configured with extension unit (1B)
Can be combined as needed.

The basic unit (1A) is a level of a general type sensor (3a) (3b) from the coupling circuit section (5) for interfacing with the signal line 1 and the line voltage extracted by the coupling circuit section (5). Signal V _L
With the level detection circuit unit (6) for discriminating each voltage level of short circuit and disconnection, and demodulating the pulse code signal which is the return signal extracted through the coupling circuit unit (5) and extracted,
A transmission signal modulation / demodulation circuit section (7) for modulating and creating a transmission signal V _S to be superimposed on the signal line 1 via the coupling circuit section (5), and level detection information and a transmission signal discriminated by the level detection circuit section (6). Read the information from the intelligence type smoke detector (2) demodulated from the modulation / demodulation circuit section (7) to determine the occurrence of fire, identify the location of fire occurrence, and disconnect the signal line l. , Determine the occurrence of short circuit, smoke detector
The function of judging the abnormality of (2), and further based on these judgment results, the fire area display corresponding to the signal line through the I / O interface (11), the fire alarm, warning notification, warning to the area It generates control outputs such as alarms, sensor error display, signal line error display, smoke control device and fire extinguishing device control, etc., and also transmits and receives information to and from the extension unit (1B) through the interface (9). Control such as sequentially creating pulse code signals for calling each intelligence type smoke detector (2) and sending to the transmission signal modulation / demodulation circuit section (7)
Arithmetic signal processing circuit unit including a CPU that performs signal processing
(8), a storage unit (10) for storing and holding the setting contents of the control operation of the arithmetic signal processing circuit unit (8), a keyboard (12) and the like. On the other hand, the extension unit (1B) is the basic unit (1A)
It is possible to send and receive data via the interface (13), and provided with a combination table of a predetermined sensor and the corresponding external equipment such as a fire extinguishing device and smoke prevention device, and a relay means. Storage unit (14) storing combination data for setting the combination of the relay means and the number of the signal line 1 to which the relay unit belongs, the data from the basic unit (1A), and the storage unit (14). Selection control of smoke prevention devices to be controlled from the setting contents, display of operating state of each sensor, display of operating state of relay means by number display of signal line 1 corresponding to relay means, and fire extinguisher or Control operations such as interlocking display that displays the operating status of smoke control devices, etc., control of smoke control devices by manual commands from the keyboard (15), and monitoring data of operating conditions of smoke control devices, etc. Performs a series of control such as input and signal processing Cormorant arithmetic signal processing circuit section (16)
And the keyboard (15), display (17), and arithmetic signal processing circuit
(16) I / O interface to interface with
(18) is provided, and the selection control data of the smoke proof device or the like is given to the basic unit (1A), and the control output of the smoke proof device or the like is generated by the basic unit (1A). Of course, the smoke proof / exhaust device may be controlled on the extension unit (1B) side. (13) ′ is an interface for expansion.

As shown in FIG. 4, the intelligence type smoke detector (2) has a body part composed of a base (2a) and a head (2b), and the internal circuit has a circuit part as shown in FIG. There is something. That is, in the head (2b), a light ray type smoke detection section (19) for detecting smoke and a zero level shift circuit for constantly detecting the zero level of the smoke detection section (19) and performing shift control so as to stabilize the zero level. The range (20), the output circuit section (21) for outputting an analog signal according to the smoke density detected by the smoke detection section (19), and the range for shifting the zero level by the zero level shift circuit section (20) Self-check circuit that detects whether or not it exceeds a specified range
(23) and, when the self-check circuit section (23) outputs a detection signal indicating that the predetermined range has been exceeded, the function stop determination circuit section (2) that determines that the function is stopped and generates an “H” signal
2) and are provided. The zero level shift circuit unit 20 and the self-check circuit unit 23 are actually A / D converters,
It is composed of a memory unit, a one-chip microcomputer with a built-in I / O, or a microcomputer externally attached thereto, and the A / D converter converts an analog signal output from the light receiving unit 19b into a digital signal by the A / D converter. . The initial value of digital signals and upper and lower limit values of the digital signal are written in advance in the memory unit at the time of manufacturing, and when the system is actually operated, under the control of the microcomputer, from the present time to a certain past period (for example, several hours to several hours). 1
During the week), the digital value output from the A / D converter is written and updated.

The micro computer calculates the average value of the digital values in the past constant period written in the memory unit for each constant period, and obtains a value obtained by subtracting the initial value previously written in the memory unit from the average value, A value is provided with an arithmetic processing function for comparing the upper and lower limit values previously stored in the memory unit, and when the value exceeds the upper limit value or falls below the lower limit value in the comparison. The function stop detection circuit 22 outputs the function stop detection signal as described above. On the other hand, the base (2a) is detachably attached to the head (2b) and supplies power to the circuit inside the head (2b) and outputs the output circuit section (21) and the function stop determination circuit section (22).
It is installed on the mounting surface such as the ceiling surface, and the analog signal from the output circuit unit (21) is discriminated into, for example, three stages and the smoke concentration data of three stages is output. Level discrimination circuit section (24) and the level discrimination circuit section (24)
Also, the output data from the function stop determination circuit section (22) is taken in and used as return information to the receiver (1), and a return signal composed of a pulse code signal based on the information is created, and an address setting section is also provided. Reception included in the transmission signal V _L when the address set in (25) matches the address signal included in the transmission signal V _L transmitted from the receiver (1) via the signal line l The information signal from the machine (1) is taken in, and the operation signal processing circuit section (26) for performing signal processing such as sending the above-mentioned return signal during the return period following the transmission signal _VL is connected to the signal line l. A coupling circuit unit (27) for extracting the transmission signal V _S or superimposing the return signal on the signal line l.
When the power is obtained through the coupling circuit section (27) and the level discrimination of the level discrimination circuit section (24) described above continues to detect the set level with a high smoke concentration, that is, the low sensitivity, for a predetermined time, the signal line 1 is appropriately turned. A short circuit is made through a resistor, and a general smoke detector (3
As in (a) and the heat sensor (3b), the line voltage level, the fail-safe circuit section (28) for sending the level signal V _L through the coupling circuit section (27) by changing the current level, the impedance level, etc., When the smoke detector is made to function as an intelligence type, or when a level signal similar to a general detector is output and a level signal is output, that is, a pulse code signal corresponding to its own address at the time of fire detection is received by the receiver. It is equipped with a type application setting part (29) that selectively sets whether to function as a so-called point address type that is transmitted to (1), and the above three-step smoke density discrimination is performed by the smoke detector.
It corresponds to the identification of species, 2 species, and 3 species, for example, 5%, 1
It is set to 0% and 15%, and the detection signal corresponding to each stage is generated when each stage is exceeded.

Now, in the receiver (1), the following operating conditions can be set in the storage unit (10) from the keyboard (12). First, in this system, in addition to the level signal V _L from the general type smoke detector (3a) and the heat detector (3b), the smoke occurrence from the intelligence type smoke detector (2) and the time function In the receiver (1) side, from the keyboard (12) to the intelligence-type smoke detectors (2), the detected smoke concentration, which is the condition for fire occurrence determination, is used. The duration of the detected smoke density can be selectively set. In other words, the detected smoke density data returned from the intelligence type smoke detector (2) has three levels, and the time is, for example, 6 seconds and 30 seconds.
There are two types of seconds, one of these detected smoke concentrations and one of the times can be combined, and the sensitivity setting of fire occurrence can be performed by two functions of smoke concentration and time. . This setting condition is for each intelligence type smoke detector (2)
It is decided according to the installation location.

In addition, the receiver (1) has multiple intelligence-type smoke detectors.
When (2) reaches the fire occurrence determination condition, the logical product alarm function is generated for the first time to generate the control output for controlling the smoke prevention device and fire extinguisher device, and logical product alarm is performed. Therefore, the address table combined with the intelligence type smoke detector (2) can be set and stored in the storage unit (10) from the keyboard (12). Further receiver
In (1), it is possible to issue a caution warning, and an address table in which each intelligence type smoke detector (2) that requires a caution warning is individually selected is stored in the storage unit (10) using the keyboard (12). The settings can be stored in. However, in the receiver (1), the transmission signal V _S is superimposed on the line voltage or current of the signal line 1 in the order of the addresses set by the storage unit (10), and the signals are sequentially and cyclically transmitted. Then, each intelligence type smoke detector (2)
Each smoke sensor (2) is called to send the information of the detected smoke density and the monitoring information of the function stop of each smoke detection unit (19) as a return signal, and each intelligence type smoke sensor (2) Check the state of.

Now, the intelligent smoke detector at the specified address (2)
When the receiver (1) receives the return signal of, the calculation signal processing circuit unit (8) determines whether or not a fire has occurred in the intelligence type smoke detector (2) stored in the storage unit (10). Compare the detected smoke concentration with the detected smoke concentration data in the return signal,
If the detected smoke density data is lower than the set detected smoke density, the arithmetic signal processing circuit unit (8) determines that no fire has occurred. On the contrary, when the smoke density is equal to or higher than the detected smoke density, the set time is counted by the fire determination timer. The built-in timer continues counting while the detected smoke density data returned by repeating the above cyclic call does not fall below the set detected smoke density. When it is determined that the set time has been exceeded, it is determined that a fire has occurred and the fire is reported by a bell (31) or the like. By the way, when the intelligence type smoke sensor (2) is set as a target for warning alert, first compare the smoke density one level lower than the set detected smoke density with the detected smoke density data. When the comparison judgment is lower in the detected smoke density data, it is judged that the caution warning is not necessary. On the contrary, when the value is high, the caution warning timer starts counting for a predetermined time. Then, while the above cyclic calling is repeated and the returned detected smoke density data does not fall below the set detected smoke density, the caution warning timer continues counting. If the detected smoke density data does not fall below the set detected smoke density level until the count-up time, the caution signal is calculated by the arithmetic signal processing circuit unit (8), and a caution warning is issued as a preliminary warning. .

By the way, when the detected smoke concentration data exceeds the set detected smoke concentration during the count period of the caution alarm timer, the fire determination timer starts counting and the above-described fire occurrence determination is performed. When the detected smoke density data falls below the set detected smoke density while the fire determination timer is counting, the count time up to the point when the data decreases is stored and added, and the count of the fire determination timer is reset. If the addition result is less than the predetermined time corresponding to the caution, the process returns to the count routine of the caution warning timer.
When the added value of the period in which the detected smoke density data exceeds the set detected smoke density reaches a predetermined time or longer, the arithmetic signal processing circuit section (8) determines that caution is required and issues a caution warning.

Now, at the time of the above-mentioned fire occurrence determination, it is also determined at the same time whether or not the intelligence type smoke detector (2) is set to perform a logical product alarm, and if not, a fire occurrence alarm is issued. It is issued from the receiver (1). Also, if it is set to perform logical product alerting, it is also determined that other intelligence type smoke detectors (2) that are set in combination with the relevant intelligence type smoke detector (2) have fired. It is judged whether or not it has been done, and if the judgment is "YES", a fire alarm is issued from the receiver (1). When a fire occurrence is determined, the receiver (1) outputs a control signal to the smoke prevention device or fire extinguisher that is set in advance corresponding to the intelligence type smoke detector (2). Each of them is activated, and the display section (17) (17) 'displays an indication of the sensor or device in operation, as well as a fire indication for each area.

It is desirable to set the above-mentioned caution alarm setting for all intelligence type smoke detectors (2), but this is not the case when the smoke density and time settings are set to low sensitivity. A smoke detector connected to the same signal line l
It may be possible to determine that a fire has occurred when at least two smoke detectors (2) of (2) issue a caution warning.

The logical product is issued when all of the combined intelligence type smoke detectors (2) are judged to have detected a fire.For example, valuable items such as a computer room and a library are installed or stored. If the intelligence type smoke detector (2) installed in the place where it is detected is detected as a fire occurrence at the beginning or on the way, it is of course possible to provide a priority determination function to determine a fire occurrence at that time. Good. Further, the logical product notification may be used in conjunction with the smoke prevention device and the fire extinguishing device to notify the occurrence of a fire when the smoke detector (2) is judged to have a fire.

FIG. 6 shows a flow chart of the arithmetic signal processing circuit section (8) relating to the above-mentioned fire occurrence determination and caution warning determination,
Further, FIGS. 7 (a) to 7 (d) show the relationship between the fire occurrence judgment, the comparison operation of the caution warning judgment, and the smoke density detected by the intelligence smoke detector (2). FIG. 7 (a) shows the set levels of the detected smoke density in three stages of I, II, and III.
The state is set to the II level, and the detected smoke concentration exceeding the II level continues for the set time T _I or more, that is, the state where the fire occurrence determination is made. Figure 7 (b) shows the setting level I
A time that exceeds _I is shorter than the set time T _I , and is one step lower than the level to distinguish cautions. A time that exceeds I is shorter than the predetermined time T _II for distinguishing cautions. It is judged that it is a temporary condition due to, and neither the alarm of fire occurrence nor the warning of caution is issued. Fig. 7
(c) shows a state in which the level I or higher continuously continues for a predetermined time T _II or longer, that is, a state in which it is determined that a caution warning is necessary due to either a fire or a setting error. Further, FIG. 7 (d) shows a state in which the total amount of time that the detected smoke concentration exceeds the set level II intermittently exceeds the predetermined time T _II , and this state needs the same caution as in FIG. 7 (c). Indicates a condition where it is determined that an alarm needs to be foamed.

However, by issuing the above-mentioned caution warning, it is possible to easily detect a setting error and to calibrate the setting sensitivity of each smoke detector (2) after system installation, thus optimizing the system without false alarms. It can be achieved.

By the way, the fire sensitivity level shift shown in the flow chart of Fig. 6 is as follows, and its setting is the receiver.
The keyboard (12) of (1) can be adapted to each different intelligence type smoke detector (2). That is, for example, if the standard sensitivity is a combination with a set time of 6 seconds and a set smoke density of 10%, the sensitivity of the intelligence type smoke detector (2) set to a lower sensitivity than this standard sensitivity is one step higher. Set the fire sensitivity level so that it becomes higher. Either the set time or the set detected smoke density corresponding to the target intelligence smoke sensor (2) or both are calculated.The signal processing circuit section (8) fires. It is switched at the time of occurrence determination. Therefore, at the same time as the fire occurrence determination, the fire detection sensitivity corresponding to the target intelligence-type smoke detector (2) becomes high, so that the spread state can be promptly detected.

By the way, it may be desirable to change the fire detection sensitivity corresponding to each intelligence type smoke detector (2) according to changes in the environment and management conditions such as daytime and nighttime, when there are people and when there are no people. The system calculates the sensitivity level shift function that switches the sensitivity of the intelligence type smoke detector (2) selected and set by the command input from the keyboard (12) or the command automatically added at the preset time. It is provided in the signal processing circuit section (8). In other words, during the daytime or during the manned period, when the malfunction such as cigarette smoke is likely to occur, switch to the low sensitivity, or conversely, when the false alarm occurs, set to high sensitivity during the daytime or during the manned period and during nighttime or unmanned period. It is set to low sensitivity. In this case, the sensitivity changing element may be programmed so as to switch the set time to a long time side or to set the set smoke concentration one step lower when the set time is set to a long time side.

Furthermore, this system is equipped with an external device such as a fire extinguisher that works in conjunction with a specified smoke detector (2) and an smoke control device to automatically detect the occurrence of flame in the corresponding smoke detector (2). When it is done, it has a link function to operate the corresponding external device, but the smoke detector linked from the keyboard (12)
When (2) is instructed and set, the interlocking level setting function is provided to automatically switch and set the set sensitivity corresponding to the smoke detector (2) to the low sensitivity side.

When the fire (1) is issued by the receiver (1) as described above, the smoke detector (2) receives the signal.
When the next access is made from (1), the alarm confirmation information is sent as the transmission signal V _S , and when the smoke detector (2) receives this information, the operation signal processing circuit section (26) works to cause the light emitting diode to operate.
(30) is turned on to display the operation. This display facilitates the determination of whether or not the system function has normally operated during a test operation such as construction and maintenance. When the intelligence type smoke detector (2) receives the notification information of the previous term, the operation of the fail safe circuit section (28) is controlled so as to stop the output as the general type detector having the backup function.

Next, the operation of the intelligence type smoke sensor (2) side will be described. The smoke detector (19) of the smoke detector (2) detects that the light emitted from the light emitting unit (19a) is scattered by the smoke or blocked by the light and is received by the light receiving unit (19b). Then, an analog signal according to the amount of received light, that is, the smoke density is generated through the zero level shift circuit section (20) and the output circuit section (21). The analog signal output from the output circuit section (21) is discriminated by the level discrimination circuit section (24) into the above-mentioned three-stage detected smoke concentration levels, and the discriminated data is the arithmetic signal processing circuit section (26). It is taken in and is sent back to the receiver (1) as the detected smoke density data via the coupling circuit section (27) based on this data. Of course, the analog signal may be A / D converted without discrimination, and the raw data of the detected smoke density may be returned. If there is a detection corresponding to the low sensitivity discriminated by the level discrimination circuit section (24), the fail-safe circuit section (28) counts this detection period with a built-in timer, and when the predetermined time is exceeded, the signal line 1 is connected to the resistance. It is short-circuited through and the level signal V _L similar to that of the general type sensor is output from the coupling circuit section (27). For example, the arithmetic signal processing circuit section (26) using a CPU may cause trouble due to noise or the like. Even if it occurs, the smoke detection signal can be generated regardless of the operation of the arithmetic signal processing circuit section (26), and the so-called back-up function can be exhibited. Of course, when the operation signal processing circuit section (26) is normal and the detected smoke concentration data is returned, the alarm confirmation information from the receiver (1) side is used to detect the smoke from the fail-safe circuit section (28) as described above. The output of the smoke detection signal is stopped. The fail-safe circuit section (28) has a level discrimination circuit section (24) provided with a discrimination function for the fourth-stage high-concentration smoke concentration detection level, and the level discrimination circuit section (24) detects this high-concentration smoke concentration. Of course, it may be configured to operate at that time.

The zero level shift circuit part (20) is an optical system part (1) of the smoke detection part (19).
This is a circuit for correcting the zero level that occurs when 9c) becomes dirty or deteriorates. In other words, if the output level of the smoke detector (19) when the smoke density is zero is set to zero level, this zero level was initially set to point A as shown in FIG. As a result, the zero level shift circuit section (20) detects this increase or decrease, and the zero level shift circuit section (20) always detects the increase or decrease to zero. It shifts the level. Here, the alternate long and short dash line and the alternate long and two short dashes line in FIG. 8 indicate the density information of the smoke detector which changes corresponding to the curve b or c. Further, the self-check circuit section (23) is a zero level shift circuit section (2
When the range of the zero level shift of (0) exceeds the range of x, x'shown in the ninth, that is, when it exceeds the detectable level, it is determined that the function is stopped and the function stop detection signal is output as the function stop determination circuit unit.
It outputs to (22). The range of the zero level shift is determined according to the smoke detection capability of the smoke detection unit (19), the permissible dirt, and the degree of deterioration. In the function stop determination circuit section (22), the output of the function stop detection signal is switched from "L" to "H" at the same time when the function of the smoke detection section (19) is stopped. ). The arithmetic signal processing circuit section (26) returns function stop data when calling from the receiver (1) to notify the receiver (1) side, and the receiver (1) side smoke of the smoke detector (2) concerned. The fact that the function of the detection unit (19) has stopped is displayed on the display unit (17) or (17) '. Therefore, with this display, the administrator can immediately replace the smoke detector (2) and prevent a false alarm.

〔The invention's effect〕

The present invention is configured as described above, the smoke detector is provided with the monitoring means for monitoring the function stop of the smoke detector, and the receiver is provided with the monitor means for detecting the function stop of the smoke sensor based on the received monitoring data. Since it is equipped with a smoke detector, the smoke detector can perform a self-check, so that the receiver side does not directly monitor the functional state of the smoke detector, but only by checking the monitoring data that is the result monitored by the monitoring means. The state of the detector can be determined, and therefore the function sharing between the receiver and smoke detector reduces the data processing load on the receiver and enables efficient operation of the system. -Type smoke detector is constantly called to monitor the smoke density data detected from the smoke detector and to monitor the function state of the smoke detector at all times, so it is possible to operate the system reliably and optimally. Can advantageously possible to obtain a high reliability. Moreover, the smoke detector sets the output level of the smoke detector when the smoke density is zero to zero level, and shifts the zero level when it is detected that the zero level rises or falls due to dirt or deterioration. It is equipped with a zero level shift circuit section and a self-check circuit section which determines that the function is stopped when the zero level shift exceeds the range of detectable levels. When the self-check circuit section outputs a function stop signal, the receiver Since the monitoring data of the function stop is sent back at the time of access, even if the smoke detection part becomes dirty or deteriorates to some extent, the zero level shift circuit part works,
The zero level of the smoke detector can be shifted to maintain it in an optimal state, resulting in some contamination of the smoke detector,
It is possible to automatically cover the deterioration and correctly transmit the smoke detection density data. Moreover, when it exceeds the range of the detectable level, it can be judged that the function is stopped by the function of the self-check circuit section. There is an effect that reliability can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic overall configuration diagram of the present invention, FIG. 2 is a signal waveform diagram used in the same as above, and FIG. 3 is a circuit block diagram of a receiver in the above,
FIG. 4 is an exploded perspective view of a body portion of the intelligence-type smoke detector of the above, FIG. 5 is a circuit block diagram of the intelligence-type smoke detector of the same, and FIG. 6 is a flow chart for explaining the operation of the same. 7 (a) to 7 (d) are the same operation explanatory diagrams as above, and FIG.
FIG. 9 and FIG. 9 are diagrams for explaining the operation of the above zero level shift circuit section. (1) is a receiver, (2) is a smoke detector, and 1 is a signal line.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-52-116196 (JP, A) JP-A-51-139299 (JP, A) JP-A-55-97690 (JP, A) Actual development Sho-58- 58687 (JP, U) Actual development Sho 56-148794 (JP, U)

Claims (2)

[Claims] 1. A smoke detector for detecting smoke density, which is connected to a receiver and a plurality of smoke detectors each having an address set by a signal line, and functions of the smoke detector. Address of the transmission signal transmitted from the receiver through the signal line, the detected smoke density data obtained by digitally converting the analog value of the smoke density from the monitoring means and the smoke detection part and the monitoring data from the monitoring means At least a transmission signal processing means for superimposing transmission on the signal line when the signal and the set address match is provided, and the smoke detector is sequentially and cyclically called by the transmission signal including the address signal of each smoke detector in the receiver. The smoke detecting density of the smoke detector is determined from the received smoke density data received, and the smoke detecting density is set corresponding to the smoke detector. Upon detecting certain set concentration exceeds the set time or Te and fire judging means judges that a fire occurs, the monitoring data received at least have a fire warning systems and monitoring means for detecting the failure of the smoke detector,
The monitoring means provided in the smoke detector sets the output level of the smoke detector when the smoke concentration is zero to zero level, and when it detects that the zero level rises or falls due to dirt or deterioration, it zeros. A zero-level shift circuit section for shifting the level and a self-check circuit section for judging that the function is stopped when the zero-level shift exceeds the detectable level range are provided, and when the self-check circuit section outputs a function stop signal. The fire alarm system is characterized in that the smoke detector returns monitoring data indicating that the smoke detector has stopped functioning to the receiver when called from the receiver. 2. In the smoke detector, the smoke detector and the monitoring means are built in the head side, the transmission signal processing means is built in the base side to which the head is detachably mounted, and the electric power is supplied from the base to the head side. The fire alarm system according to claim 1, wherein the fire alarm system is provided.