JPH08305989A - Disaster preventive monitor device - Google Patents

Abstract

PURPOSE: To prevent the disconnection of a free line from being misdetected with a simple circuit constitution. CONSTITUTION: Fire sensors 5 are connected to plural lines 4 led out of a receiver 1, terminators 6 for disconnection monitoring are connected to the terminals of the respective lines 4, and fire detection detection signals from the fire sensors, etc., are received by the receiver 1 to perform disaster preventive monitoring. The receiver 1 is provided with a disconnection detecting circuit 3, which inputs the inter-line voltage of the line 4 and detects its disconnection from a rise in the inter-line voltage due to the disconnection on every line, and a switch 11 which stops inputting the line voltage in case of a free line is provided for the input line of the inter-line voltage to the disconnection detecting circuit 3. The disconnection detecting circuit 3 has a comparator which detects the rise in the input voltage at the time of the disconnection and a switch 11 is provided for the input line of the inter-line voltage to the comparator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disaster prevention monitoring device for receiving a fire detection signal from a fire detector or the like at a receiver for disaster prevention monitoring, and particularly to stop the disconnection detection function for an empty line. Disaster prevention monitoring device.

[0002]

2. Description of the Related Art In a conventional disaster prevention monitoring device, a fire detector is connected to each of a plurality of lines drawn from a receiver, and a termination device for disconnection monitoring is connected to the end of each line to detect a fire detector. The fire detection signal from the etc. is received by the receiver for disaster prevention monitoring. Further, the receiver is provided with a disconnection detection circuit for each line, and detects the disconnection from the increase in the line voltage due to the disconnection by inputting the line voltage of the line.

By the way, not all of the plurality of lines are connected to the fire detector, and some lines are idle. In general, since a terminator, for example, a terminating resistor is not connected to the vacant line, there is a disadvantage that the disconnection detection circuit detects the disconnection even though the terminating circuit is the vacant line as it is. In order to eliminate such inconvenience, free line processing is performed so that disconnection detection is not performed in the case of a free line.

FIG. 3 is a block diagram of a conventional disaster prevention monitoring device. In FIG. 3, the receiver 1 has a receiving circuit 2 and a disconnection detecting circuit 3. Further, a line 4 composed of two power source / signal lines is drawn from the receiving circuit 2 of the receiver 1, and one or a plurality of fire detectors 5 are connected to the line 4. At the end of the line 4, for example, a terminating resistor is connected in parallel with the fire detector 5 as a terminating device. Although only one line 4 is shown, in reality, a plurality of lines are used for the receiver 1.
Is more drawn.

The signal lines 4a and 4b in the receiver 1 from which the line 4 is drawn out are input and connected to the disconnection detection circuit 3. When the line 4 is broken, the disconnection detection circuit 3 detects the disconnection from the increase in the line voltage because the line voltage rises, and issues an alarm. Further, in order to perform the idle line processing, a resistor R having an impedance equivalent to that of the terminator 6 and a dip switch 7 are connected in series between the signal lines 4a and 4b. When the line 4 is drawn out and the fire detector 5 and the terminator 6 are connected as shown in the figure, the dip switch 7 is turned off. On the other hand, if the line is free, the dip switch 7 is turned on. When the DIP switch 7 is turned on, the signal lines 4a and 4b are connected by the resistor R, a circuit equivalent to the case where the terminator 6 is connected to the line 4 is formed in a pseudo manner, and disconnection detection is performed even on an empty line. It is possible to prevent erroneous detection of disconnection by the circuit 3.

[0006]

However, in such a conventional device, the series circuit of the resistor R and the switch 7 is mounted on the printed circuit board by the number of all the lines in order to process an empty line that does not cause the disconnection detection circuit to malfunction. Therefore, there is a problem that the number of components increases, the printed circuit board becomes large, and the cost also increases.

The present invention has been made in view of the above problems of the conventional device, and an object thereof is a disaster prevention monitoring capable of preventing disconnection detection malfunction of an empty line with a simple circuit configuration. To provide a device.

[0008]

In order to achieve this object, the present invention is constructed as follows. First of all, the present invention connects a fire detector to each of a plurality of lines drawn from a receiver, and also connects a termination device for disconnection monitoring to the end of each line to send a fire detection signal from the fire detector or the like. In the disaster prevention monitoring device for receiving disaster prevention monitoring by the receiver, each line is provided with a disconnection detection circuit for inputting the line voltage of the line into the receiver and detecting the disconnection from the rise in the line voltage due to the disconnection. ,
It is characterized in that the input line of the line voltage to the disconnection detection circuit is provided with a switch for blocking the input of the line voltage in the case of an empty line.

Here, the disconnection detection circuit has a comparator for detecting an increase in the input voltage at the time of disconnection, and a switch may be provided on the input line of the line voltage to the comparator.

[0010]

In the present invention, since it is only necessary to provide a switch on the input line of the line voltage to the disconnection detection circuit, specifically, the input line of the line voltage to the comparator, a pseudo terminator is used in the conventional receiver. As compared with the case of using a series circuit of a switch and a resistor for connecting to each other, since the resistor is not required, the circuit configuration can be simplified and the number of parts can be reduced, and the cost can be reduced.

Further, since the comparator of the disconnection detection circuit does not operate by turning off the switch for processing the idle line, the current consumption can be reduced.

[0012]

FIG. 1 is a block diagram of a disaster prevention monitoring device according to the present invention. In FIG. 1, the receiver 1 has a receiving circuit 2 and a disconnection detecting circuit 3. Also, the receiving circuit 2 of the receiver 1
From this, a line 4 consisting of two power source / signal lines is drawn out, and one or a plurality of fire detectors 5 are connected to this line 4. As a terminator 6, for example, a terminator is connected to the end of the line 4 in parallel with the fire detector 5. Line 4
Shows only one line, but a plurality of lines are actually drawn from the receiver 1.

The line 4 is a signal line 4a, 4a in the receiver 1.
The signal lines 4a, 4b are connected to the disconnection detection circuit 3 by input. Disconnection detection circuit 3
A switch 11 used for free line processing is provided in the middle of the input line for. This switch 11
Fire detector 5 and terminator 6 by line 4 as shown
Is turned on when is connected, and turned off when the line is idle.

In such a structure, if a disconnection occurs in the normal line 4 in which the switch 11 is turned on,
The disconnection detection circuit 3 detects this. That is, a prescribed power supply voltage is applied from the receiver 1 to the line 4, and when the line 4 is normal, the impedance of the terminator 6 and the receiving circuit 2
It is a specified line voltage determined by the voltage division with the internal impedance of.

If the line 4 is disconnected, the terminator 6
The disconnection of the line 4 puts the line 4 in a no-load state, so that the line voltage increases, and based on the increase in the line voltage, the disconnection detection circuit 3 detects the disconnection and issues an alarm. If the line is free,
Since there is no line connection, the power supply voltage is applied as it is to the voltage between the signal lines 4a and 4b, which is the same voltage as when the line 4 is disconnected. However, for such an empty line, the switch 11 is processed by the empty line processing.
Since the signal is turned off, the line voltage of the signal lines 4a and 4b is not applied to the disconnection detection circuit 3 to prevent malfunction of disconnection detection.

FIG. 2 is a circuit diagram showing an embodiment of the disaster prevention monitoring device according to the present invention. In FIG. 2, the receiving circuit 2 is provided with a transistor TR1, and a signal line 4 on the + side is provided.
A resistor R1 for current detection is connected to a, and the reception voltage generated across the resistor R1 is applied between the emitter and base of the transistor TR1. A bias circuit including resistors R2 and R3 is provided on the base side of the transistor TR1.

Further, the signal line 4a is provided with a resistor R for limiting current.
It is connected to the line 4 via K0. A Zener diode ZD0 for keeping the line voltage of the line 4 constant is connected between the signal lines 4a and 4b on the input side of the resistor RK0. A latching transistor TR2 is connected to the transistor TR1. That is, the collector of the transistor TR1 is connected to the base of the transistor TR2 via the bias circuit of the resistors R5 and R6, and the transistor TR2 is connected.
Is connected to the base of the transistor TR1 via a resistor R4.

When the line current increases due to a short circuit between the lines 4 caused by the fire detector 5 issuing a warning, and the transistor TR1 begins to shift to the ON state due to the received voltage of the resistor R1, the transistor TR2 is also turned on in response to the collector current. Then, the base current of the transistor TR1 is further made to flow, and this interaction causes the transistors TR1 and TR2 to be latched in the ON state.

The collector of the transistor TR1 is further connected to the transistor TR3 via a bias circuit of resistors R7 and R8.
When the transistor TR1 is turned on and the transistor TR3 is turned on, the transistor TR3 is turned on, and a fire detection signal is output to a control unit (not shown) to display an alarm. The emitter of the transistor TR2 is connected to a latch release section (not shown) via the diode D5. The latch release part is
Transistor TR via switch circuit for latch release
The emitter of 2 is connected to the ground side, and by disconnecting this switch circuit, the transistor TR2 is turned off and the latch of the transistor TR1 is released.

The disconnection detection circuit 3 includes a comparator 10. The comparator 10 has a resistor R17 at the + input terminal,
A reference voltage determined by the divided voltage of R18 is input. The-input terminal of the comparator 10 has a switch 11 and a resistor R connected between the signal lines 4a and 4b on the receiving circuit 2 side.
13 and R12 are connected to the voltage dividing point b of the series circuit. That is, the comparator 10 divides the line voltage applied between the signal lines 4a and 4b by the voltage dividing circuit of the resistors R13 and R12 and inputs it.

As the switch 11, for example, a DIP switch is used, and when the line 4 is connected as shown in the figure, it is turned on, and when it is a free line, it is turned off as a free line process. The position where the switch 11 is provided is from the connection point a of the signal line 4a to the resistors R13 and R1.
It is desirable that the pressure is between 2 and the partial pressure point b. During this time switch 1
If 1 is provided, the switch 11
Is turned off, the signal line 4a is connected to the comparator 1
At the same time as disconnecting from the-input terminal of 0,
The negative input terminal of 0 is connected to the ground on the signal line 4b side via the resistor R12, and malfunctions due to noise input to the comparator 10 can be prevented.

On the other hand, from the voltage dividing point b to the comparator 1
When the switch 11 is provided on the signal line between the 0 input terminal and the 0 input terminal, the − input terminal of the comparator 10 floats from the ground due to the turning off of the switch 11 due to the vacant line processing, and a malfunction easily occurs. For this reason,
It is necessary to connect a noise absorbing capacitor to the-input terminal of the comparator 10.

The output of the comparator 10 is resistors R14 and R
It is connected to the base of the transistor TR5 via a bias circuit of 15. L is for the collector of the transistor TR5
The broken area indicator lamp 12 using the ED is connected through the resistor R16 and the diode D1. When the line 4 is normal, the signal lines 4a, 4 obtained via the switch 11
The line voltage between b is applied to the-input terminal of the comparator 10 as a divided voltage by the resistors R13 and R12,
17 and R18 are below the reference voltage, the output of the comparator 10 is at the H level and the transistor T
R5 is off.

When the line 4 is broken, the signal line 4
The line voltage between a and 4b rises to around the power supply voltage + 24V, the voltage applied to the-input terminal of the comparator 10 also rises and exceeds the reference voltage, and the transistor TR5 is turned on by the L level output of the comparator 10. When the transistor TR5 is turned on, the disconnection area indicator lamp 12 is turned on to notify the disconnection.

On the other hand, for the vacant line, the switch 11
Is turned off as shown. At this time, since the line 4 is not connected, the line voltage of the signal lines 4a and 4b rises to around the + 24V power supply voltage as in the case of disconnection. However, since the switch 11 is in the off state, the line voltage of the signal lines 4a and 4b is equal to that of the comparator 1.
It is separated from 0, the-input terminal of the comparator 10 is connected to the ground via the resistor R12, and the input voltage is 0V.
Fixed to. Therefore, the output of the comparator 10 is maintained at the H level and the disconnection detection is suppressed.

Next, the operation of the embodiment shown in FIG. 2 will be described. First, in the case of the normal line 4 in which the line 4 is pulled out from the receiver 1 and the fire detector 5 and the terminator 6 are connected, the switch 11 is turned on. If there is no disconnection in this state, the input voltage of the − input terminal of the comparator 10 becomes lower than the reference voltage of the + input terminal, the output of the comparator 10 becomes H level, the transistor TR5 is off, and the disconnection area indicator lamp 12 Is also off.

On the other hand, when a disconnection occurs, the line 4 becomes unloaded, the line voltage between the signal lines 4a and 4b rises, the voltage at the-input terminal of the comparator 10 exceeds the reference voltage, and the output of the comparator 1 is output. Becomes L level. When the output of the comparator 10 becomes L level, the transistor TR5 is turned on and the disconnection area indicator lamp 12 is turned on to notify the occurrence of disconnection.

Next, when the line 4 is not connected and is a free line, the switch 11 is turned off. When the switch 11 is turned off, the negative input terminal of the comparator 10 is fixed to OV, which is lower than the reference voltage, so that the output of the comparator 10 is fixed to the H level and the transistor TR5.
Is off and the disconnection area indicator lamp 12 is off. In other words, it is possible to prevent accidental disconnection detection display on an empty line.

Incidentally, as the terminator 6, an appropriate element using a Zener diode or a capacitor can be used in addition to the terminator.

[0030]

As described above, according to the present invention, as a circuit for processing an empty line for preventing the malfunction of the disconnection detection circuit, a switch is applied to the signal line for inputting the line side line voltage to the disconnection detection circuit. By setting the switch and turning off the switch for the idle line, it is not necessary to provide the conventional circuit configuration for connecting the terminator to the idle line for each line in the receiver, and the number of parts is reduced. Therefore, the circuit configuration can be simplified, and as a result, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a disaster prevention monitoring device according to the present invention.

FIG. 2 is a circuit diagram showing a specific example of FIG.

FIG. 3 is a block diagram of a conventional disaster prevention monitoring device.

[Explanation of symbols]

 1: Receiver 3: Disconnection detection circuit 4: Line 5: Fire detector 6: Terminator 10: Comparator 11: Switch 12: Disconnection area indicator lamp TR1 to TR5: Transistor

Claims (2)

[Claims] 1. A fire detector is connected to each of a plurality of lines drawn from a receiver, and a terminator for disconnection monitoring is connected to the end of each line to detect a fire detection signal from the fire detector or the like. In the disaster prevention monitoring device for receiving disaster prevention by receiving at the receiver, the disconnection detection circuit for inputting the line voltage of the line to the receiver and detecting the disconnection from the rise of the line voltage due to the disconnection A disaster prevention monitoring device, characterized in that a switch is provided for each line, and a switch is provided on an input line of the line voltage to the disconnection detection circuit to block the input of the line voltage when there is an empty line. 2. The disaster prevention monitoring device according to claim 1, wherein the disconnection detection circuit has a comparator for detecting an increase in input voltage at the time of disconnection, and the switch is provided in an input line of the line voltage to the comparator. A disaster prevention monitoring device characterized by being provided.