JPH0719314B2 - Analog fire alarm - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an analog fire alarm device that detects smoke concentration, temperature, gas concentration, etc. associated with a fire as an analog amount, sends the analog amount to a receiver, and determines a fire from detection data received on the receiver side.

[Prior art]

A conventional fire alarm device uses a so-called on / off type fire detector that closes contacts when a fire is detected and sends a warning signal to a receiver, but it is called early detection of fire and prevention of false alarm. It was difficult to completely solve the two problems. Therefore, in recent years, a so-called analog fire alarm device that sends detection data of the analog amount such as temperature and smoke density detected by the detector to the receiver as it is and judges the fire from the data detected by the receiver side. In particular, the inventor of the present application executes a prediction calculation by a function approximation method as a method of fire judgment based on detection data of analog amount, and a person survives a fire from the prediction of the fire situation by this prediction calculation. It proposes a method to determine the time to reach a dangerous level that is set as an impossible level and to judge that a fire occurs when the time to reach the dangerous level is less than a certain time.

[Problems to be Solved by the Invention]

However, when the receiver side makes a relatively high-class fire judgment by predictive calculation processing based on the analog amount detection data, the detection data of all analog sensors is taken in by polling from the receiver and the fire judgment is made for each sensor. When the processing is executed, the polling cycle of the detection data by polling becomes longer as the number of sensors increases, and when predictive calculation of fire judgment etc. is executed for the detection data of a specific sensor, the CPU of the receiver will be in a busy state. As a result, polling of other sensors is suspended, and the processing load on the receiver CPU becomes too heavy, resulting in a limitation of the number of sensors. Furthermore, the detection data of the analog amount sent from the sensor also includes fluctuations due to noise, and if it is used as it is for fire judgment, it will be an erroneous fire judgment, so it will be included in the received detection data when making a fire judgment. Pre-processing to remove unnecessary noise components is required, and this pre-processing makes the receiver CPU more burdensome.

[Means for solving problems]

The present invention has been made in view of such problems,
An object of the present invention is to provide an analog fire alarm device that reduces the load on the receiver CPU that executes fire determination processing and can increase the number of installed analog sensors per receiver. To achieve this object, in the present invention, the analog sensor itself is provided with a means for sampling an analog detection signal at a constant cycle and performing an averaging calculation of noise removal from the sampling data. The pre-processing calculation is unnecessary, and the data transmission in response to the polling from the receiver is allowed only when the averaged calculation data becomes equal to or higher than a predetermined threshold level.

Embodiment FIG. 1 is a block diagram showing the basic configuration of the present invention. First, the configuration will be described. 1 is a receiver, which has a built-in CPU for executing fire determination processing. An analog sensor 3 is connected to each of the signal lines 2a to 2n drawn from the receiver 1, and the analog sensor 3 changes in physical phenomena accompanying a fire, specifically, temperature, smoke concentration, CO gas concentration. Is detected as an analog amount, an analog detection signal is output, and the detection data is sent in response to polling from the receiver 1 based on the averaging calculation and the comparison judgment with the threshold value which will be made clear later, for example, the current mode. To send. FIG. 2 is a block diagram showing an embodiment of the analog sensor 3 used in the present invention. In FIG. 2, the analog sensor 3 operates by receiving power supply from the receiver 1, and includes an analog detection unit 4 including an element that detects temperature, smoke density, etc. as an analog amount and outputs an analog detection signal. Have. Reference numeral 5 denotes a sampling circuit, which samples the analog detection signal at a constant cycle. The sampling data from the sampling circuit 5 is A /
The detected data is digitally converted by the D converter 6 and given to the averaging calculator 7. The averaging calculator 7 executes a moving average calculation and a simple average calculation of the detection data. That is, as shown in FIG. 3, the average value (MEAN) of each of the three detection data obtained in sequence is sequentially calculated, and then the simple average value of the six data obtained by the moving average calculation is calculated. Produces one detection data to be sent to. The averaging calculation process consisting of this moving average calculation and simple average calculation realizes the function as a reduction digital filter that removes the harmonic components generated by the fundamental frequency component of the fire temperature or smoke included in the analog detection signal. However, the original signal can be faithfully reproduced by passing through the reduction digital filter. Also, since the analog detection signal is sampled and digitally converted into detection data, the probability of capturing it as detection data is low even if pulse noise occurs, and even if it is captured as detection data, sufficient noise suppression will be achieved by averaging calculation. Can be multiplied. Reference numeral 8 denotes a digital comparator, which compares the output data from the averaging calculation unit 7 with the sensor threshold data from the reference data setting unit 9 and instructs the data transmission when the averaging calculation data is equal to or higher than the sensor threshold data. It produces an H level output. Here, as the threshold data set in the digital comparator 8, for example, when detecting a fire temperature, a threshold temperature corresponding to an upper limit of a normally expected indoor temperature, for example, 30 degrees is set, Data transmission to the receiver 1 is allowed only when the above detection data is obtained. Reference numeral 12 is a call discrimination unit, which counts clock pulses transmitted from the receiver 1 in, for example, a voltage mode, and when it reaches a clock count value assigned to itself, determines that it is a call and outputs a data transmission signal (H level). Signal) is output. The outputs of the call discriminating unit 10 and the digital comparator 8 are input to the AND gate 11, and the AND gate 11 gives an H level output to the signal transmitting unit 12 when the detected data is a certain value or more and the self call is discriminated. At that time, the averaging calculation data output from the averaging calculation unit 7 is set to D / A
After conversion, it is sent to the receiver 1 in the current mode. FIG. 4 is a block diagram showing an embodiment of the receiver shown in FIG. 1, in which the call control unit 13 and the CPU 1 for executing fire judgment processing are shown.
4. An A / D converter 15 for digitally converting an analog reception signal from the sensor into a detection data signal, and a display unit 16 are provided. The call control unit 13 performs sensor polling by repeatedly outputting a reset pulse having a long pulse width in a voltage mode after a number of clock pulses corresponding to the analog sensor connected to the receiver 1. The A / D converter 15 inputs the voltage of the resistor 17 based on the detection current sent from the sensor, digitally converts it into detection data, and gives it to the CPU 14. The CPU 14 collects the detection data corresponding to the sensor address determined by the count of the clock pulse, determines the fire by the predictive calculation by the function approximation method, and displays the fire together with the sensor address on the display unit 12, as will be described in detail later. To perform. Next, the fire determination process based on the detection data by the CPU 14 of the receiver 1 will be described. The content of this fire determination process is divided into the following two. Protective processing of non-fire alarm b. Predictive calculation of fire by function approximation method Fig. 5 shows the threshold levels used for fire judgment of a and b and the threshold level for signal transmission control set in the analog sensor 3. In the fire judgment, the calculation start level for starting the prediction calculation by the function approximation method, and the danger level for obtaining the remaining time from the prediction result until reaching the fire are provided. On the other hand, the threshold level of the analog sensor is set to a level that removes stationary noise that is lower than the operation start level. Therefore, when the level of the data averaged and calculated by the analog sensor is lower than the threshold level indicated by the white circle, no signal is transmitted even if the receiver is polled, and only the detected data that exceeds the threshold level indicated by the black circle is received by the receiver. Sent to. As a result, only the data indicated by white circles is the receiver CPU
Burden will be reduced. FIG. 6 is a flow chart showing an example of the fire judgment processing performed by the receiver CPU, and the prediction calculation by the quadratic function approximation method is executed. First, in block 20, it is checked by polling whether there is response data. If there is response data, the process proceeds to the next decision block 21, and it is checked whether the latest data sent by averaging calculation and above the sensor threshold value exceeds the operation activation level shown in FIG. . Here, the receiver CPU has a function of sequentially storing 20 pieces of detection data LD1 to LD20 for calculation processing by the quadratic function approximation method. When the latest received detection data LD20 exceeds the operation activation level, the process proceeds to the block 22 non-fire protection process. In the non-fire protection process, the amount of change between the four data LD17 to LD20, including the data LD20 that exceeds the operation start level,
That is, the slopes y1, y2, y3 are detected. FIG. 7 shows an example of detecting the slopes y1 to y3. In this case, the slope y1 is negative and the slopes y2 and y3 are positive. Furthermore, the specified slope y that is set in advance for the positive slopes y2 and y3
Check if k or more, and the number of slopes that are yk or more n
To count. When the number n of slopes equal to or greater than yk is 2 or more as shown in FIG. 8, there is a risk of fire and the prediction calculation by the function approximation method in the next block 23 is started. On the other hand, as shown in FIG. 7, when the number of slopes equal to or greater than yk is less than 2, it is determined that the data has changed due to cigarette smoke, and the prediction calculation by the function approximation method is not performed. For the data that has passed the non-fire protection processing of block 22, the prediction calculation of block 23 is executed. In this prediction calculation, the time changes of temperature and smoke density at the time of fire were approximated by y = ax ² + bx + c, and 20 data LD1 obtained by averaging calculation were calculated.
The values of the coefficients a, b, c of the quadratic function shown in FIG. The calculation of the coefficients a, b, and c can be performed by calculating a simultaneous equation consisting of a determinant by the least square method by the Gauss-Jordan method. If the coefficients a, b, and c can be calculated, the trajectory of future data changes can be obtained as shown in FIG. Therefore, in the next block 24, the time tr at which the danger level is reached is obtained from the quadratic function of FIG. 10, and the danger level arrival predicted time Tpu is calculated from the current time tn. In the determination block 25, the shorter the dangerous level reaching time is, the more true the fire is. Therefore, for example, the threshold time is compared with 800 seconds, and when it is 800 seconds or less, it is determined that the fire occurs, and the fire alarm is issued in the block 26. In addition to the quadratic function approximation method, the prediction calculation by the function approximation method of the receiver CPU may be performed by a linear function y = ax + b, and both the linear function and the quadratic function may be performed. You may

【The invention's effect】

As described above, according to the present invention, since the analog sensor executes the averaging calculation for removing the noise component of the detection data used for the fire determination process, the receiver that executes all the detection data. The pre-processing calculation of the CPU can be made unnecessary, and of the detection data obtained by the averaging calculation,
For detection data that is less than the specified sensor threshold, the analog sensor prohibits signal transmission to the receiver, and the signal transmission is started after reaching the specified sensor threshold.
The number of analog sensors that are subject to fire judgment is greatly reduced, and the load on the receiver CPU can be significantly reduced.
With more margin, the number of connected sensors can be increased.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of the present invention, FIG. 2 is a circuit block diagram showing a position embodiment of an analog sensor, and FIG. 3 is an explanatory diagram showing an averaging calculation process performed by the analog sensor. FIG. 4 is a block diagram showing an embodiment of a receiver, FIG. 5 is an explanatory diagram showing a relationship between a sensor threshold level and a threshold level used for fire judgment on the receiver side, and FIG. 6 is a receiver CPU 7 and 8 are explanatory views of the non-fire protection processing of the receiver CPU, FIG. 9 is an explanatory view of the quadratic function prediction calculation by the receiver CPU, and FIG. 10 is the receiver. It is explanatory drawing of the dangerous level reaching time calculated by CPU. 1: Receiver 2a to 2n: Signal line 3: Analog sensor 4: Analog detector 5: Sampling circuit 6: A / D converter 7: Averaging calculator 8: Digital comparator 9: Reference data setting unit 10: Call discrimination Part 11: AND gate 12: Signal sending part 13: Call control part 14: CPU 15: A / D converter 16: Display part

Claims (1)

[Claims] 1. A plurality of analog sensors are connected to a signal line drawn from a receiver, the analog sensors are sequentially called from the receiver to send detection data, and the receiver judges a fire based on the received detection data. In the analog fire alarm device, an analog detection unit that detects temperature, smoke density, etc. as an analog amount and outputs an analog detection signal, and a sampling unit that samples the analog detection signal at a constant cycle. An A / D converter that digitally converts an analog detection signal sampled by the sampling unit into detection data; an averaging calculation unit that performs averaging calculation of the detection data over a fixed time to obtain averaging calculation data; The value of the averaging calculation data is compared with a preset sensor threshold value, and the averaging calculation data exceeds the sensor threshold value. A comparing unit that outputs a command signal when the receiver determines that a call from the receiver is detected, and when the call determining unit determines a call from the receiver, based on the command signal from the comparing unit. An analog fire alarm device, comprising: a data signal transmitting section for transmitting the averaged calculation data as detection data to the receiver.