JP2000113341A - Signal transmission device and monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a signal transmission device which can show not only the deviation of a head but also a device fault. SOLUTION: A signal transmission device such as a fire detection device has a head 2 which can be removed from a base 1. The head 2 has circuit means 4, 5 and 6 sensing the change of a prescribed state and transmitting a signal. The base 1 connected to a supply line has a fault signal transmission generating a fault signal by the deviation of the head 2 or the fault of the other device. Since the same signal is generated in respective cases, an economical, simple and reliable solution against a problem at the time of transmitting a fault state signal is obtained. The fault signal transmission means contains a first circuit 3 in the base 1 making a response to the output of a second circuit 7 in the head 2. When the head 2 is deviated from the base 1, a first circuit 3 applies the fault signal to a supply line in response to the absence of the output of the second circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a signal transmission device (si)
gnalling device) and monitoring system. This signal transmission device includes a head detachable from a base and circuit means for applying a device failure signal to a power supply line.

[0002] The invention can be used in the field of fire detection. In the art, for example, fire detection devices (ie, signal transmitters) are located at various locations within a fire detection system (ie, a monitoring system) to detect a fire and generate an alarm signal. Has become.

[0003] The present invention can also be used to generate a device failure signal, for example, when the head of a fire detector is removed from the base and not attached to the base after maintenance. The signal sending device may be an alarm device having a sounder head detachable from the base. However, in this case, the present invention also generates a device failure signal due to the head detachment as described above. Used to do.

[0004] Thus, the term "signaling device" can be used for any kind of signaling, and any function can be impaired by head detachment.
Used in a broad sense, including all types of equipment. Although the present invention is particularly useful in the field of fire detection, reference to use in the art does not limit the interpretation of the invention.

[0005]

2. Description of the Related Art In places where fire alarm systems are used to protect lives and property, fire detection devices and alarm devices are generally replaced by central control units (Centra) according to national regulations and codes of practice.
l There is a need to monitor the supply lines connecting to the Control Unit (CCU). This is for knowing the occurrence of a failure such as a circuit opening or a short circuit occurring in the supply line, displaying the state of such a failure in the central control unit, and generating a supply line failure alarm.

The transmission of fault signals is used in a small number of fire systems, most notably in France. In this type of system, the detection device sends a device failure signal by switching between a condition close to a short circuit and a condition having approximately twice the impedance between supply lines used to signal fire detection. .

[0007]

A disadvantage of the above system using a device fault signal caused by a short circuit is that while one of the detectors is sending a device fault signal, the other detector which is not faulty Is inoperable.

[0008] A disadvantage that arises when using a method other than a short circuit to send a fault signal is that if two detectors are faulty, the central controller will combine the fault signals sent by the two detectors. Is interpreted as a fire alarm.

Another system disclosed in British Patent Publication No. 2178878 and commonly known as an analog addressable fire detection system transmits a fire signal and a fault signal from a detection device to a control device. Use digital communication protocols.
However, these systems require the use of more complex and expensive electronic circuits for the detector and controller as compared to conventional systems that do not allow address calling.

A British patent application (No. 981) of the same applicant
No. 0900.2) (Japanese Patent Application No. 11-140814), the detailed description of which is left to the description in the same application, but a "head off signal" is generated in the form of a pulsation signal. in this case,
The head-off signal or device failure signal only indicates that the head is not attached to the base.

[0011] The present invention seeks to provide a signal transmitting device that can clarify not only a case where the head is not attached to the base but also a device failure caused by some problem occurring in a circuit of the signal transmitting device. Is what you do.

The present invention also seeks to provide a cost-effective and reliable solution.

[0013]

The signal transmitting device of the present invention includes a base and a head detachable from the base. The head has circuit means for sensing a change in a predetermined state and transmitting a signal, and for supplying a detection signal to the base (when the head is attached to the base). The base has a failure signal transmitting means for supplying a failure signal when the head is displaced from the base or when another failure that impairs the function of the signal transmission device occurs. The base also has terminals for connecting the base to a supply line to which the detection signal and / or the failure signal or both are applied. Then, when the head is attached to the base and the other fault does not exist, the fault signal is not applied to the supply line, and the head is disengaged from the base or the other fault exists. When this occurs, the fault signal is applied to the supply line.

The present invention provides an economical, simple and reliable solution because only the fault signal is generated, whether the head is off or another fault. It does not matter whether the same fault signal indicates head off or another fault. Because, as long as the fault signal is present, a test of the system containing the signaling device is required before it can be returned to service, and that test reveals (among other things) a missing head. It is.

The "other failure" does not mean that the head is detached from the base, but is a predetermined circuit failure that usually occurs in a circuit of the signal transmission device. For example, in the case of a fire detection device, the failure signal generating means includes a microprocessor, and the microprocessor monitors the operation of the circuit that senses a fire and supplies a fire detection signal to the supply line. You may.

The fault signal can be generated in any condition that degrades the performance of the fire detection device. The condition may be, for example, a condition in which the limit of compensation has been reached in some detectors that compensate for long-term drift in the output of the fire detector. Other examples of equipment failures include:
A failure of a voltage regulator that supplies a voltage to an ionization chamber of an ionization (ionization) smoke detector can be cited. For example, an open or short circuit of a temperature sensing device such as a thermistor in a heat detector, or a light emitting diode (Light Emitti) in a photoelectric smoke detector.
There is a stop of the oscillator which sets the timing of pulse application to the ng Diode (LED). Known circuit means may be provided for monitoring the device failure or responding to the device failure to generate the failure signal. The circuit means may include a microprocessor.

It is preferable that the failure signal is not set to a value or type that is likely to be confused with, for example, a fire detection signal. In the present invention, a British patent application (No. 9810)
900.2) (Japanese Patent Application No. 11-140814), a pulsation signal indicating that the head is not attached to the base can be used. The pulsation signal is, for example, by a central controller that continuously monitors the supply line to detect a fire detection signal.
This is because it can be easily recognized. The fire detection signal may be a signal that allows the detection device to change from a high impedance state to a low impedance state, thereby detecting a decrease in current flowing through the supply line. Preferably, the fault signal is also selected such that it does not create a severe current drain on the supply lines and does not impair the operation of other signal delivery devices connected to those supply lines. In the present invention, it is not essential to use a pulsation signal. This is because other kinds of recognizable signals can be used instead of the pulsation signal. In the present invention, the same signal is generally used to indicate head off and other device failures.

A monitoring system according to the present invention includes a plurality of the signal transmitting devices according to the present invention, and monitoring means for monitoring the signal transmitting devices in response to the detection signal or the failure signal. This monitoring means is provided by the central control unit (CC
U) or a line end device (EOL)
Or any other means.

[0019]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In general, centrally controlled fire alarm systems typically include a central control unit (CCU) that monitors various groups of fire detection devices located in various parts of the building. Each of these groups of fire detectors can be connected between a pair of common power supply lines linked to the central controller. The central controller typically operates, for example, 12
A voltage of V is applied to the supply line. Between the supply lines, a group of alarm devices which can be activated at a voltage higher than that voltage (12 V) may be connected, in which case the central control unit sends a "fire detection signal" sent through the supply line. Higher voltage (eg, 24V) in response to
Can be applied to the supply line, thereby generating an "alarm signal" to the alarm system. According to this fire alarm system, it is possible to avoid an excessive amount of wiring as compared with a fire alarm system in which the fire detection device group and the alarm device group are respectively connected to dedicated supply lines.

When the two-wire fire alarm system is in a standby state, the supply voltage is lower than a threshold voltage (for example, 18 V), and each of the fire detection devices has a high line impedance value. Is not pulled at all from the power supply, or is pulled at all. When a fire is detected, the fire detection device that detects the fire generates a fire detection signal by changing from a high line impedance value to a low line impedance value. This change in line impedance is effected, for example, by switching a known resistor connected between the supply lines. The fire detection signal thus generated is detected by the central control device. Thereafter, the central controller applies the high voltage (for example, 24V) between the supply lines. Then, since the voltage between the supply lines exceeds the threshold voltage (for example, 18 V), the group of alarm devices is activated to generate a fire alarm signal. In order to prevent a large current drain from occurring when the high voltage (for example, 24V) is applied, the fire detection devices include means for limiting the current drawn by the fire detection devices between the supply lines. Such a system is disclosed in commonly assigned UK Patent Application No. 98080.
94.8 (Japanese Patent Application No. 11-108229), the details of the system will not be described here.
Instead of or in addition to the increase in the voltage between the supply lines, another alarm device may generate a fire alarm signal by reversing the polarity of the power supply.

Referring to FIG. 1, a fire detection device according to an embodiment of the present invention includes a base 1 for installation and a detection head 2 detachable from the base 1. The base 1 has a terminal L1IN for connecting to a pair of supply lines.
And L2. Base 1 is disclosed in British Patent Application No. 9810900.2 (Japanese Patent Application No. 11-14) filed by the same applicant.
No. 0814), the signal transmission circuit 3 is included. When the head 2 is removed, the signal transmission circuit 3 senses that the input signal sent from the head 2 is no longer present at the terminal L1OUT of the base 1. In the absence of the input signal, the signal transmission circuit 3 applies a predetermined impedance to the supply line (terminal L).
1IN and L2). This will generate a fault signal and inform the central controller of the fault condition (ie, head off). The central control unit directly detects this failure signal or uses the same applicant's UK Patent Application No. 9810900.2 (Japanese Patent Application No. 11-140814).
End-of-Line Device,
EOL).

The head 2 includes a fire detection circuit 4 for detecting a fire, a signal processing circuit 5 for processing the output of the fire detection circuit 4, and a fire detection signal when the signal processing circuit 5 determines that a fire has occurred. Detection signal generation circuit 6 that generates
And This fire detection signal is used to operate an alarm device group (not shown).

The head 2 also has a terminal L1OU of the base 1.
A failure signal sending circuit 7 for applying a signal to a terminal of the head 2 corresponding to (engaging) T is included. The failure signal transmission circuit 7 operates in response to the determination that the signal processing circuit 5 is in a failure state, and removes the signal applied from the head 2 to the terminal L1OUT. As a result, the signal transmission circuit 3 provided in the base 1 can respond to both the head detachment and other failure states. The same fault signal is generated by the signal transmission circuit 3 in the base 1 in both the case of the head detachment and other fault conditions.

In the simplest embodiment of the present invention, the signal processing circuit 5 can include a threshold sensing means that operates in response to the output of the fire sensing means 4. In a preferred embodiment of the present invention, the signal processing circuit 5 is constituted by a device such as a COP 8ACC5 microcontroller or a microprocessor manufactured by National Semiconductor.

In another embodiment of the present invention, the signal processing circuit 5 and / or the fault signal sending circuit 7 are arranged in the base 1. In this case, when a failure is determined and the head 2 is still applying a signal to the terminal L1OUT of the base 1, a failure signal sending circuit 7 is provided by a switching circuit or a logic circuit (not shown) having a known configuration. Is configured to operate the failure / head-off signal transmission circuit 3.

The fire detecting device according to one embodiment of the present invention preferably includes an indicator connected to switching means that operates in response to the signal processing circuit 5. In this case, when the signal processing circuit 5 determines that a failure has occurred, the state of the indicator changes or an encoded signal is generated so that the failed fire detection device can be more easily identified. Is preferred.

The signal processing circuit 3 in the base 1 is used when the fire detection device has a certain fault condition.
It is preferable to include means for applying a pulsation signal to the terminals L1IN and L2. In this case, when other pulsation signals are already present on the supply lines, the signal sending circuit 3 is also activated to substantially preserve the waveform of the pulsation signal on those supply lines. As a result, the waveform of the pulsation signal is removed from the heads 2 separated from the respective bases 1.
Is independent of the number. This point is described in the UK patent application (No. 9810900.2) of the same applicant (Japanese Patent Application No. 11-1).
No. 40814).

According to another embodiment of the present invention, the base 1
Signal processing circuit 3 in the case where the voltage applied to the fire detection device exceeds a predetermined threshold, the polarity of the voltage applied to the fire detection device changes, or both of them occur And means for stopping the pulsation signal (ie, the device failure signal).

FIG. 2 is a circuit diagram showing a configuration example of the signal processing circuit 3. The operation of the signal processing circuit 3 is described in the UK patent application (No. 9810900.2) of the same applicant.
(Japanese Patent Application No. 11-140814).

That is, the signal processing circuit 3 shown in FIG. 2 comprises a bridge rectifier composed of diodes D3, D4, D5 and D6 enabling the detection device to operate in either positive or negative polarity, and resistors R5, R6, R7, R8, R9 and R10, a capacitor C1, diodes D7, D8 and D9, and a relaxation oscillator (relaxation oscillator) including bipolar transistors T3 and T4. This oscillator (R5, R6, R
7, R8, R9, R10, C1, D7, D8, D9, T
3, T4) can be replaced, for example, by a functionally equivalent circuit based on programmable unijunction transistors.

This relaxation oscillator (R5, R6, R7, R
8, R9, R10, C1, D7, D8, D9, T3, T
4) is that the switch means, that is, the transistor T2 is OF
When the state becomes F (cutoff state), the operation is stopped. When the transistor T1 is turned on (conductive state), that is, when the terminal L1OUT is connected to the negative supply line or when the rectified supply voltage is higher than the threshold voltage determined by the Zener diode ZD1. The transistor T2 is turned off. (The latter condition occurs when the supply line voltage increases after a fire is detected and the alarm is activated.) One example of such a system is:
It is disclosed in British Patent Application No. 9808094.8 (Japanese Patent Application No. 11-108229) of the same applicant.

When the terminal L1OUT is connected to the positive supply line, the transistor T2 is also turned off. At this time, the base current of the transistor T2 is the diode D
The power is supplied to a positive power supply via the power supply 6. Thus, when both supply lines are not connected to terminal L1OUT, ie when head 2 is removed from base 1 and the supply voltage is lower than the threshold voltage determined by Zener diode ZD1, the oscillator (R5, R6, R7, R8, R9,
R10, C1, D7, D8, D9, T3, T4) start operating. The output of this oscillator turns on the transistor T5, for example, for 10 milliseconds at 5 second intervals. When the transistor T5 is ON, a resistor R11 having a low resistance value is used.
Is connected between the two terminals of the rectifier (D3, D4, D5, D6), thereby causing the circuit 3 to periodically have a low line impedance. The periodic application of a low impedance value between the supply lines produces a fault signal indicating that the head 1 has been removed. The voltage between the supply lines is such that the output impedance value of the power supply is
Is pulsed to a value lower than (1/2) of the normal supply voltage.

The oscillators (R5, R6, R7, R8, R9,
The operation of R10, C1, D7, D8, D9, T3, T4) begins with the capacitor C1 being slowly charged (in 5 seconds) via the resistor R5 and the diode D7. Next, when the voltage of the capacitor C1 exceeds the threshold voltage,
The transistor T3 is turned on. This threshold voltage is equal to the voltage at the junction of the two resistors R9 and R10 forming the voltage divider plus the forward bias voltage of diode D9 and transistor T3. When the transistor T3 is turned on, the transistor T4 is turned on, whereby positive feedback is applied to the transistor T3 via the diode D8. This causes the capacitor C1 to discharge rapidly until the transistors T3 and T4 are turned off for a time period (10 milliseconds) controlled by the resistance value of the resistor R7. Thereafter, the capacitor C1 starts charging again. The voltage at the junction of resistors R9 and R10 forming the voltage divider, and thus the threshold voltage, is almost proportional to the supply voltage.

When the capacitor C1 is charged after the head 2 is removed from the base 1, the threshold voltage becomes lower than the voltage of the capacitor C1 due to the decrease of the supply voltage, so that the capacitor C1 can be discharged earlier. It becomes possible. Such a situation occurs when the head 2 has been removed from another fire detection device in advance and the signal transmission circuit 3 in the fire detection device has already applied a failure signal to the supply line. The capacitors C1 in the signal sending circuits 3 of the two fire detectors are discharged simultaneously, and the two oscillators (R5, R6, R7, R
8, R9, R10, C1, D7, D8, D9, T3, T
4) operates synchronously. Of those two oscillators,
The oscillator with the higher frequency determines the frequency to which it is synchronized. Similarly, when a number of heads 2 are disengaged from their bases 1, the fault signals generated by removal of these heads 7 are synchronized with each other. To ensure this synchronization, the supply voltage should be reduced to a value lower than (1/2) of the normal supply voltage by the pulse portion of each fault signal.

Preferably, the capacitor C1 is not discharged prematurely by an extraneous disturbance source that generates a transient (transient) negative voltage pulse on the supply line. One way to accomplish this is to connect a capacitor C2 across resistor R10 (ie, in parallel with resistor R10). The time constant of the combined circuit of the capacitor C2 and resistor R9 and resistor R10 connected in parallel is longer than the expected longest transient voltage duration, but the oscillator reduces the impedance between the supply lines to a low impedance value. The time is set sufficiently shorter than the time required for switching. Preferably, a surge protection element CR1 for limiting a transient (surge) voltage to a low voltage level is provided between terminals L1IN and L2.

The fault signal generated by the removal of the head 2 in the fire detection device can be recognized by the microprocessor means of the central control unit monitoring the voltage on the supply line. When the microprocessor means recognizes a fault signal on the supply line, it is possible to generate a fault alarm signal. Further, where a line end device (EOL), such as a resistor, is used to stabilize the current being monitored, a fault signal generated by removal of the head 2 may indicate an open or short circuit condition on the supply line. Can be distinguished from

FIG. 3 shows a head 2 of the fire detecting device according to the present invention.
FIG. 3 is a circuit diagram showing an example of the internal configuration of the device. Terminal L1O of FIG.
The UT is engaged with the terminal L1OUT of the base 1.

When no fault exists, the output labeled "FAULT" of fault signal processing circuit 5 is set high to turn on open collector transistor 8. Thus, when there is no failure, the terminal L1OUT is set to the negative polarity, that is, active pull-down is performed. On the other hand, when it is determined that a failure state has occurred, the transistor 8 is turned off, and removes the negative signal from the terminal L1OUT. Then, the signal transmission circuit 3 in the base 1 is operated, and the signal transmission circuit 3 transmits a failure signal.

The circuit configuration including the transistors 9 and 10 and a fault display indicator (indicator) 11 composed of an LED indicates a simple means for visually notifying that the fire detection device has a fault.

More complicated fault display means can also be used. For example, when the fire detection device is operating normally, a single indicator is blinking. However, when the fire detection device has a failure, the indicator stops blinking or the number of times of blinking ( The frequency can change, or the color of the blinking of the indicator changes, and when a fire is detected, the indicator can be lit continuously.

In FIG. 3, reference numeral 12 denotes an indicator for indicating fire made up of LEDs, 13, 14, 15, 16, and 17 are diodes, 18 is a surge protection element, 19 is a transistor, and R12, R13, R14, R15, R16, and R1.
7, R18, R19 and R20 are resistors.

The transistor 19 is connected to the fault signal processing circuit 5
Is driven by an output named “FIRE”, and as a result, the presence or absence of a fire is displayed by the indicator 12.

[Brief description of the drawings]

FIG. 1 is a block diagram of a fire detection device having a base and a removable head according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration example of a base of the fire detection device of FIG. 1;

FIG. 3 is a circuit diagram showing a configuration example of a head of the fire detection device of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Base of fire detection device 2 Head of fire detection device 3 Failure / head detachment signal transmission circuit 4 Fire detection circuit 5 Signal processing circuit 6 Fire detection signal generation circuit 7 Failure signal transmission circuit 8, 9, 10, 19 Transistors 11, 12 Indicator (LED) 13, 14, 15, 16, 17 Diode 18 Surge protection element 19 Transistor L1IN, L1OUT, L2 Terminal on base of fire detector CR1 Surge protection element ZD1 Zener diode D1, D2, D3, D4, D5 , D6, D7, D8, D
9 Diodes T1, T2, T3, T4, T5 Transistors R1, R2, R3, R4, R5, R6, R7, R8, 8
9, R10, R11, R12, R13, R14, R1
5, R16, R17, R18, R19, R20 resistors C1, C2 capacitors

 ──────────────────────────────────────────────────の Continuation of the front page (71) Applicant 599053034 36 BROOKSIDE ROAD, H AVANT, HAMPSHIRE PO 91 JR, UNITED KINGD OM (72) Inventor Roger Dennis Payne P.O. , Havant Road, 13

Claims (10)

[Claims] 1. A signal transmitting device in which a head (2) is detachable from a base (1), wherein the head (2) detects a change in a predetermined state and transmits a signal, Circuit means for supplying a detection signal to said base (when (2) is attached to said base (1)), said base (1) comprising: The base (1) includes a failure signal generation unit (3) that generates a failure signal when the signal transmission device deviates from (1) or when another failure that impairs the function of the signal transmission device occurs. Also has terminals (L1, L2) for connecting the base (1) to a supply line to which the detection signal or the failure signal or both are applied, and wherein the head (2) is Attach to base (1) And when the other fault is not present, the fault signal is not applied to the supply line, and when the head (2) is off the base (1) or the other fault is present, The signal transmission device, wherein the failure signal is applied to the supply line. 2. The fault signal generating means includes a first circuit (3) provided in the base (1), wherein the first circuit (3) is provided in the head (2). When the head (2) is disengaged from the base (1), the output of the second circuit (7) is configured to operate in response to the output of the second circuit (7). 2. The signal transmission device according to claim 1, wherein the signal transmission device operates in response to the absence of the control signal to apply the failure signal to the supply line. 3. The signal transmission device for detecting a change in a predetermined state and transmitting a signal to supply the failure signal to the first circuit. 3. The signal transmission device according to claim 2, wherein a predetermined failure occurring in the circuit of (1) can be detected. 4. The threshold value sensing means (5), wherein said circuit means (4, 5, 6) for sensing a change in a predetermined state and sending out a signal.
Wherein the threshold sensing means (5) responds to the output of the sensing circuit (4) when the output of the sensing circuit (4) rises above a predetermined threshold due to the change of the predetermined state, whereby the third circuit ( The signal transmission device according to claim 1, wherein the signal transmission device is driven to apply a signal corresponding to the change to the supply line. 5. The base (1) includes a processing circuit (5), wherein the processing circuit (5) includes the fault signal generating means (3).
However, when the head (2) is attached to the base (1) but is in a state where the other fault exists, the fault signal is applied to the supply line. 3. The signal transmission device according to claim 1. 6. The apparatus further comprises an indicator means for generating an alarm signal indicating that the failure signal has been applied to the supply line, so that it is possible to identify whether or not the signal transmission device has failed. The signal transmitting device according to claim 1. 7. The signal transmission according to claim 1, wherein the failure signal is stopped when a line voltage of the supply line exceeds a predetermined threshold value or when the polarity of the line voltage changes. apparatus. 8. A method according to claim 1, wherein said fault signal has reached its compensation limit in a compensation means for compensating for drift in said means for sensing a change in said predetermined state. Signal transmission device. 9. A plurality of signal transmission devices having a configuration according to claim 1, and monitoring means for monitoring the plurality of signal transmission devices in response to the detection signal or the failure signal. A surveillance system comprising: 10. The monitoring means according to claim 1, wherein said monitoring means comprises a central control unit (CC).
10. The monitoring system according to claim 9, wherein the monitoring system is a part of U) or an end-of-line device (EOL).