JPH0444797B2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] The present invention relates to a self-fire alarm system.

[Background Art] Conventionally, in this type of self-fire alarm system that uses both a general type sensor and an intelligence type sensor, monitoring time periods are set for the general type sensor and the intelligence type sensor, respectively. Furthermore, by differentiating the voltage of the signal line for each time period, in other words, the voltage during the monitoring time period of the intelligence type sensor is lowered, and the current consumption during data transmission of the intelligence type sensor is suppressed. A self-fire alarm system has been proposed, but it is also desired to easily realize short-circuiting and opening of the signal line and monitoring the operation of a general-purpose sensor connected to the signal line while reducing current consumption. ing. By the way, in a system using a signal line with a terminating resistor connected to the end, if the load on the signal line increases due to the connection of an intelligence type sensor with a repeater for constant monitoring, there is a method to reduce the value of the terminating resistor. However, it was difficult to detect the opening. In other words, this method has the disadvantage that the current consumption on the signal line due to the terminating resistor increases all the time. A method has also been proposed in which a pulsed high voltage is applied to the signal line and a Zener diode connected to the terminal end detects the pulse current flowing through the signal line, but the configuration for applying the high voltage is complicated. Moreover, it has the disadvantage of high cost.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a self-fire alarm system that can monitor signal lines with a simple configuration and with low current consumption. There is something to do.

[Disclosure of the Invention] The present invention will be explained below with reference to Examples. Figure 1 shows a basic schematic configuration diagram of a self-fire alarm system, in which a signal line led out from a receiver 1 includes an intelligence type sensor 2, a general type smoke detector, etc., a heat sensor, etc. A general type sensor 3 is also connected. The receiver 1 superimposes a transmission signal V _S consisting of a pulse code signal including an address signal individually assigned to each intelligence type sensor 2 on the line voltage (or current) of the signal line l and sequentially sends it out cyclically. Then, it judges the information sent as a return signal RS from each called intelligence type sensor 2, and also monitors the line voltage and line current level of the signal line l to detect the general type sensor. It performs various control operations such as receiving a level signal according to the sensing operation from 3. Figures 2a to 2e show signal formats, and figure a shows the normal voltage of the signal line l (for example, 24V) and the voltage when transmitting the transmission signal V _S to the intelligence sensor 2. (peak is 12V), and receiver 1 shows the transmission signal
The line voltage in the above transmission time period A is divided into time period A for transmission of V _S and return signal RS, time period C for monitoring the general type sensor 3, and time period B for monitoring the signal line 1. The voltage is set to be lower than the line voltage in other time periods B and C. Figures b to d are time charts showing the state in which the transmission signal V _S is sequentially switched and transmitted to each signal line l, and b is the time chart for the transmission signal V _S of the first signal line l.
, c shows the transmission time period A of the transmission signal V _S of the second signal line l, and d of the same figure shows the transmission time period A of the largest signal line l of this system. In each transmission time period A of each signal line l, a transmission signal V _S is transmitted from the receiver 1 to sequentially access all the intelligence type sensors 2 connected to each signal line l. At the same time, the intelligence type sensor 2 transmits a return signal RS. Then, when all the transmissions are completed, the transmission time period A of the next signal line 1 is switched and set, and all the intelligence type sensors 2 connected in the same way are sequentially accessed. When the access on all lines l is completed, the access returns to the first signal line l. In this way, the transmission signal _VS is time-division multiplexed and cyclically transmitted from the receiver 1, and the return signal RS is sent back from the sensor 2. The intelligence type sensor 2 can have its own address set, and the transmission signal V _S sent from the receiver 1
When the address signal included in the VS matches the self-set address, the control data in the transmission signal _VS is taken in, and various information is sent as a return signal consisting of a pulse code signal during the return period provided at the end of the transmission signal _VS. The signal is superimposed and sent back to the receiver 1 as an RS. When the general type sensor 3 detects a predetermined smoke concentration or temperature, it turns on and short-circuits the signal line l through an appropriate resistor to change the level of the line current or rotational voltage, etc., and sends it as a level signal to the receiver 1. It is designed to transmit a fire detection signal. Furthermore, the second
Figure e shows the relationship between the transmission signal _VS and the return signal RS.

In normal operation, the receiver 1 sequentially switches the signal line l connected to each intelligence type sensor 2, switches the line voltage of each line l, and superimposes and transmits the transmission signal V _S to sequentially call each intelligence type sensor. A short circuit or an open circuit of the signal line l is detected by taking in the sensing information from the type sensor 2 and making a judgment, and detecting the voltage or current level of the signal line l during the monitoring time period B of the signal line l. In addition, the operation of the general type sensor 3 is monitored during the monitoring time period C of the general type sensor 3.

Next, examples of the present invention will be described. FIG. 3 shows a block diagram of an embodiment of the system based on the above-mentioned basic schematic configuration, in which a terminator 4 is connected to the end of each signal line 1, provided with means for switching the terminating impedance. On the other hand, receiver 1 is connected to each line l.
A changeover switch for sequentially switching between
SW ₁ ... are provided for the number of lines, and by switching the changeover switch SW ₁ ..., the signal transmission/reception control circuit section 5 and the general type sensor 3 connected to the line are operated for sensing, and the signal line l is short-circuited. A return signal extracted from a comparator circuit section 6 for monitoring the opening and further from the signal transmission/reception control circuit section 5.
A signal processing circuit unit 7 that processes the transmission signal V _S sent to the signal line l via the RS and signal transmission/reception control circuit unit 5, and processes the monitoring signal from the comparator circuit unit 6, and a signal processing circuit unit 7 to each signal line l. The signal transmission/reception control circuit section 5 includes a power supply section (not shown) that applies voltage, and a signal transmission/reception control circuit section 5 has a transmission signal connected to a signal line l.
It is composed of a coupling circuit 8 that superimposes V _S and extracts the current of the return signal RS superimposed on the signal line l, and a return signal current detection circuit 9 that demodulates the return signal RS from the extracted current of the signal line l. Ru. The terminator 4 is a Zener diode ZD ₁ as shown in Figure 4.
A series circuit of resistors R ₁ and R ₂ is connected between the terminal ends of the signal line l, and the connection point of these resistors R ₁ and R ₂ is connected to the base of the transistor Tr ₀ via the capacitor C ₀ . Tr ₀ is connected to both ends of the signal line l via a termination impedance switching resistor R ₃ , and a series circuit of this transistor Tr ₀ and a resistor R ₃ is connected in parallel to the termination resistor R ₀ . be done.

As shown in FIG. 5, the comparator circuit section 6 divides the voltage of the signal line 1 with resistors R ₄ and R ₅ , applies this divided voltage to the non-inverting input terminal of the comparator 10, and further connects the non-inverting input terminal and the ground line. There is a resistance R ₆ between
and the transistor Tr ₁ , and further connect the non-common line of the signal line l to the resistor R ₈ through the series circuit of the resistor R ₇ and the Zener diode ZD ₂ to the base of the transistor Tr _1. The other end of resistor _R8 is connected to the ground line. The signal processing circuit section 7 of the receiver 1 is composed of a logic circuit using, for example, a CPU,
There is a function to set each time period A, B, and C, and the monitoring signal of the comparator circuit section 6 is input, and depending on the input timing, that is, the monitoring time period B and C in which the signal is input, it is determined whether it is a fire signal or not. A monitoring discrimination function to determine whether there is a line abnormality, a line switching function to sequentially switch the signal line l according to the transmission of the transmission signal V _S , and a predetermined signal format of the transmission signal V _S , such as a start signal, an address signal,
A transmission signal creation function that forms a control signal and a return standby signal in that order and sends it to the signal transmission/reception control circuit unit 5, and a function that takes in the return signal RS and determines the sensing information of the intelligence type sensor 2. It is equipped with a control function that displays or issues an alarm in the event of a fire or line abnormality, as well as displaying an address display, line number display, etc. on a display (not shown). It is. Thus, the receiver 1 sequentially switches the changeover switches SW _{1 .} . . cyclically. By this switching, the voltage applied to the signal line l connected to the signal transmission/reception control circuit section 5 is changed to the resistance applied between the starting ends of the signal line l.
This is the voltage across the series circuit of R ₄ and R ₅ . In other words, the 24V voltage supplied from the power supply is divided by the Zener diode ZD ₀ and the series circuit of resistors R ₄ and R ₅ , and the line voltage is divided by the Zener diode ZD 0.
The voltage is reduced by subtracting the voltage across ZD ₀ , for example, 12V, which is half of 24V. On the other hand, during the time period when this voltage is dropped, that is, the transmission time period A, the transmission signal is sent from the signal processing circuit section 7 to the coupling circuit 8.
V _S will be superimposed on the signal line l. Then, the intelligence type sensor 2 at a predetermined address connected to the signal line l called out in the transmission time period A is connected to the signal line l via an appropriate impedance during a period corresponding to the return standby signal after the control signal. The sensed information is transmitted as a return signal RS in current mode by short-circuiting. The return signal RS is demodulated via the coupling circuit 8 and the return signal current detection circuit 9, and is taken into the signal processing circuit section 7, where it is determined whether a fire is occurring or normal.

Next, when the transmission time period A of the transmission signal V _S is switched from the signal line l to the next signal line l by the changeover switch SW ₁ , the resistor R ₉ is used instead of the Zener diode ZD ₀ in the signal line l. is the resistance R ₄ ,
It is connected in series to the _R5 series circuit, resulting in a line voltage rise to approximately 24V. This approximately 24V
When the voltage rises, the Zener diode ZD ₁ of the terminator 4 becomes conductive, and the transistor Tr ₀
Let the base current flow through the capacitor C ₀ to the base of . Therefore, the transistor Tr ₀ is turned on, and the resistor R ₃ is connected in parallel to the terminating resistor R ₀ to lower the terminating impedance. This period during which the terminal impedance is low is the period until the capacitor C ₀ is charged and the base current stops flowing; that is, this period is the line monitoring time period B. 6a and 6b show the relationship between the transmission time period A and the monitoring time period B of the signal line l. Now, when the termination impedance decreases in this way, the line current increases during that period. This increase in line current causes the voltage across resistors R ₄ and R ₅ to generate a predetermined voltage. Here, if the load resistance connected to the signal line 1 is set to a predetermined value or higher, the voltage becomes a voltage higher than the predetermined voltage. Therefore, if the reference voltage applied to the inverting input terminal of the comparator 10 of the comparator circuit section 6 is set to be lower than that, the comparator 10 will generate an "H" monitoring signal if the line is normal. If the signal line l is short-circuited at an arbitrary position, the line current increases further and the resistance R ₈
The voltage across it increases. When this voltage exceeds the Zener voltage of the Zener diode ZD ₂ and the Zener diode ZD ₂ becomes conductive, the transistor Tr ₁ is turned on and the comparison input of the comparator 10 is lowered to below the reference voltage. Therefore, the comparator 10 is turned on and its monitoring output is set to "L". Furthermore, when the signal line 1 is opened (broken) at any point, the terminal impedance is separated from the line, leaving only the load impedance. When only this load impedance exists, the line current decreases and the comparison input of the comparator 10 becomes lower than normal. If the maximum voltage drop is calculated from the pre-limited load impedance and the reference voltage of the comparator 10 is set higher than this voltage, the comparator 10 will turn on in the same way as in the case of the line short circuit described above.
The output is set to "L". Therefore, in the signal processing circuit section 7, if the monitoring signal of the comparator circuit section 6 is "H" in the monitoring time period B shown in FIG. 7b, the line is normal, and as shown in FIG. ”, it is determined that an abnormality has occurred, and an alarm or display is issued.
FIG. 7a shows a time chart of line voltage.

Next, when the transistor Tr ₀ of the terminator 4 is turned off and the monitoring time period C of the general sensor 3 begins, only the terminating resistor R ₀ is connected as the terminating impedance. In this case, the termination impedance increases, so the line current decreases, but by setting the value of the termination resistor _R0 so that the comparison input voltage of the comparator circuit section 6 does not fall below the reference voltage, it is possible to 3 does not operate, the output of the comparator 10 of the comparator circuit section 6 becomes "H".

That is, if the monitoring signal is "H", this indicates that the general sensor 3 is operating normally, and if the monitoring signal is "H", the signal processing circuit section 7 determines that there is no fire outbreak. Now, in the general type detector 3, a series circuit consisting of a resistor R ₁₀ , a Zener diode ZD ₃ , and a sensor contact s is connected to the signal line 1. When the sensor contact s turns on at the same time as fire detection, a low resistance value is detected. The signal line l is short-circuited via a series circuit of a resistor R ₁₀ and a Zener diode ZD ₃ with a Zener voltage of 10 V, for example. Therefore, the signal line l
The voltage between the starting terminals of the comparator circuit section 6 decreases.
The comparison input voltage of the comparator 10 becomes below the reference voltage. Therefore, the output of the comparator 10 becomes "L", and the signal processing circuit section 7 determines that if the monitoring signal becomes "L" in the monitoring time period C of the general type sensor 3, as shown in FIG. It is determined that this is the case and takes actions such as warning or display.
Here, in order to reduce current consumption, the voltage of the signal line 1 may be lowered to the same level as the transmission time period A as soon as the sensing operation is determined. Of course, when a thyristor is used in place of the sensor contact s, it goes without saying that the values of the Zener diode ZD ₃ and the resistor R ₁₀ should be set so that the holding current can be maintained even if the line voltage drops. FIG. 8 shows another example of the general type sensor 3. This general type sensor 3 uses the voltage drop that occurs in the resistor _R11 when the sensor contact s is closed to generate a confirmation light consisting of a light emitting diode.
It is designed to light up an LED.

FIG. 9 shows the comparator circuit section 6 of the receiver 1,
A specific example circuit of the coupling circuit 8 and the return signal current detection circuit 9 of the signal transmission/reception control circuit section 5 is shown,
In this embodiment, the output of the comparator 10 of the comparator circuit section 6 provided for each line is sent to the signal processing circuit section 7 via the corresponding photocoupler 11. In addition, line switching is performed by driving the photocoupler 12 with a scan signal from the signal processing circuit unit 9, turning off the transistors Tr ₂ and Tr ₃ of the switching unit 13, and turning on the transistor Tr ₄ to switch the signal line via the transistor Tr ₄ . 1 is connected to the transmission/reception control circuit section 5.
A photocoupler 12 is provided for each line and is sequentially driven by scan signals. Also, photocoupler 1
When transistors Tr 2 and Tr 3 are off, transistors Tr ₂ and Tr ₃
is turned on and the signal line l is connected via transistor Tr ₂ .
The line on the non-common side of is grounded via resistor _R9 . Thus, a circuit X consisting of a comparator circuit section 6 and a switching section 13 is provided for each line. A coupling circuit 8 of the signal transmission/reception control circuit section 5 connects a transistor Tr ₅ for current detection between the point where the outputs of the switching sections 13 provided corresponding to each signal line 1 are commonly connected and the ground. with resistance R ₁₂ ,
It is configured by connecting a series circuit with a Zener diode ZD ₀ whose Zener voltage is 12V, and when the data of the transmission signal V _S is sent from the signal processing circuit section 7 through the photocoupler 14, it is transmitted through the transistor Tr ₆ . The transistor Tr ₅ is turned on and off in response to the data of the transmission signal V _S , and when it is on, the line voltage is set to 12V with the Zener diode ZD ₀ , and when it is off, the Zener diode with a Zener voltage of 5V is connected in parallel to the transistor Tr ₅ . The transmission signal _VS is superimposed on the line voltage by ZD ₄ and the Zener diode ZD ₀ . On the other hand, the return signal RS is a return standby signal of the transmission signal V _S , that is, it is sent as the line current level when it is "H", and this current mode signal is converted to the voltage across the current detection resistor _R12 . It is detected by The return signal current detection circuit 9 amplifies this detected voltage with an amplifier 15, discriminates it into noise and signal with a comparator 16, and shapes the waveform to generate a return signal.
It demodulates the RS. And this return signal RS
is sent to the signal processing circuit section 9 via the photocoupler 17. In the figure, 18 is an amplifier for generating a reference voltage for the comparator 16.

The circuit configuration of the intelligence type sensor 2 is as shown in FIG. 10, for example, as a smoke sensor. In other words, the base 19a and the head 19b constitute a body part, and the head 19b includes output circuit parts 23a and 23b that respectively output analog signals according to the light reception levels of the light receiving elements 21a and 21b.
and light emission control sections 25a and 25b that control the light emission of the light emitting elements 24a and 24b. In the smoke detection unit 20, a light emitting element 24a and a light receiving element 21a are arranged facing each other, a light emitting element 24b and a light receiving element 21b are arranged facing each other, and the light from the light emitting element 24a is directly received by the light receiving element 21a, and the light from the light emitting element 24b is directly received by the light receiving element 21a. is directly received by the light receiving element 21b, the scattered light emitted from the light emitting element 24a is received by the light receiving element 21b, and the scattered light of the light emitted from the light emitting element 24b is received by the light receiving element 21a. The light emitting element 24a and the light receiving element 21b form the first sensing system, and the light emitting element 24b and the light receiving element 21a form the first sensing system.
The two sensing systems constitute a second sensing system, and in a normal alert state, both sensing systems operate alternately. On the other hand, the base 19a has the head 19b removably attached thereto, and the head 19a
The output circuit section 23 supplies power to the circuit in b.
a, 23b outputs and light emission control units 25a, 25b
It controls the output circuit section 23.
Signal conversion circuit units 26a and 26b that A/D convert analog signals from a and 23b and output digital received light level data, and the signal conversion circuit unit 26
a, 26b, and sends it as return information to the receiver 1, creates a return signal V _S consisting of a pulse code signal based on the information, and the address set by the address setting section 27;
The control data of the transmission signal V _S transmitted from the receiver 1 via the signal line l is taken in to control each light emission control section 25a, 25b, and the transmission signal
During the return waiting period following V _S , the above return signal V _S
an arithmetic signal processing circuit section 28 that performs signal processing such as transmitting a signal, and a coupling circuit section 29 that couples the signal line l and extracts the transmission signal V _S or superimposes the return signal RS onto the signal line l; and a power supply section 30 that obtains power through the coupling circuit section 29.

The above comparator circuit section 6 is used to monitor the signal line 1 and the general type sensor 3, but
A separate comparator circuit section may be provided. Further, the receiver 1 may be constructed from a repeater that relays signals to other systems. Furthermore, the signal line l may be monitored as follows. In other words, the total line voltage is
As shown in Figure 1 a, b, and c, the voltage is manually lowered all at once to a low voltage level, and then a monitoring time period B' is created for each signal line l, so that signal line l can be monitored at any time. You can also do this. Further, instead of the receiver 1 described above, a receiver 1 having a function as a repeater for other systems may be used.

[Effects of the Invention] The present invention provides a transmission time period for transmitting a transmission signal and a return signal, a monitoring time period for monitoring a signal line, and a monitoring time period for monitoring a general type sensor in the above-mentioned self-fire alarm system. and a signal line voltage switching means for setting the line applied voltage of the signal line in the transmission time period of the transmission signal to be lower than the line applied voltage in other time periods.
The current consumption of the intelligence type sensor during access can be reduced, and it also detects the rise in line voltage when switching from the transmission time period to the monitoring time period of the next signal line, and connects it to the end of the signal line. Since it is equipped with a termination impedance switching means that increases the line current by setting the connected termination impedance low during the monitoring time period of the signal line, the current consumption can be reduced compared to the case where the termination impedance is always small. As a result, it is less affected by load impedance and has the effect of reliably detecting an open signal line. Moreover, the circuit configuration is simpler and the cost is lower than when generating pulsed high voltage. This effect is achieved.

[Brief explanation of drawings]

Fig. 1 is an overall schematic circuit block diagram that is the basis of the present invention, Fig. 2 is a time chart for explaining the operation of the same as above, Fig. 3 is a circuit block diagram of an embodiment of the present invention, and Fig. 4 is the same as above. The circuit diagram of the terminator, Fig. 5 is the circuit diagram of the comparator circuit section same as above, Fig. 6 is an explanatory diagram of the operation of the above terminator, Fig. 7 is an explanation diagram of the operation of the comparator circuit section, and Fig. 8 is the circuit diagram of the same as above. A circuit diagram of another example of a general type sensor, Fig. 9 is a specific circuit diagram of the main part of the receiver used in the above, Fig. 10 is a block diagram of the main part of the intelligence type smoke detector used in the above, Fig. 11 is an explanatory diagram of the operation of another embodiment same as above, 1 is a receiver, 2 is an intelligence type sensor, 3 is a general type sensor, 4 is a terminator, 6 is a comparator circuit section,
10 is a comparator circuit section, A is a transmission time period, B
is the monitoring time period of the signal line, C is the monitoring time period of the general type sensor, V _S is the transmission signal, and l is the signal line.

Claims (1)

[Claims] 1. A general type sensor that short-circuits a signal line via impedance as appropriate during sensing operation, and when an address is individually assigned and a transmission signal containing the address data is superimposed on the signal line and received, a return signal is superimposed on the signal line. The above-mentioned transmission signal, which consists of an intelligence type sensor and a pulse code signal containing address data individually assigned to each intelligence type sensor, is superimposed on the line voltage or line current on the signal line. The signals are then cyclically and sequentially time-division multiplexed, and the sensed information sent as a return signal from each called-up intelligence sensor is judged, and the line voltage or line current level of the signal line is monitored. In a self-fire alarm system comprising a receiver that detects the sensing operation of a type sensor and monitors the signal line based on the level of line current flowing through the signal line terminator, the transmission signal and the return signal are transmitted. means for time-divisionally sequentially setting a transmission time period for monitoring a signal line, a monitoring time period for monitoring a signal line, and a monitoring time period for monitoring a general type sensor; Signal line voltage switching means that sets the voltage lower than the line applied voltage in other time periods, and signal line voltage switching means that detects the rise in line voltage when switching from the transmission time period to the next signal line monitoring time period. 1. A self-fire alarm system characterized by comprising: a terminal impedance switching means connected to the terminal end of the signal line, which sets the terminal impedance low during a monitoring time period of the signal line to increase the line current.