JP7382140B2 - fire alarm equipment - Google Patents

Description

The present invention relates to fire alarm equipment that monitors fires by connecting a terminal including a fire detector and a short circuit isolator to a loop transmission path from a receiver.

Conventionally, in fire alarm equipment known as type R, a terminal device such as a fire detector equipped with a transmission function is connected to a transmission line led out from a receiver, and when a fire is detected, the fire alarm Based on the fire interrupt from the system, a search command is issued to identify the address of the fire detector that triggered the alarm, display the address where the fire occurred, and collect and monitor fire data from the identified fire detector. There is.

In this way, knowing the address of the fire detector that detected the fire makes it possible to carry out appropriate evacuation guidance and fire extinguishing activities, making it an essential function especially for fire monitoring in large-scale facilities.

In addition, in order to ensure reliability against disconnection failures in the transmission line led out from the fire receiver, fire alarm equipment is installed that monitors fires by connecting a fire detector to the loop transmission line connected to the receiver in a loop. It has been known.

FIG. 10 is an explanatory diagram of a fire alarm system using a conventional loop transmission line. As shown in FIG. 10, a transmission path 12 using a pair of signal lines is led out from a transmission unit 100 provided in a receiver 10, and after being led out from the receiver 10, the transmission path 12 is connected to the receiver 10 again. Arranged in a loop that goes back. In the following description, the transmission line 12 connected in a loop to the receiver 10 will be referred to as the loop transmission line 12.

A fire detector 16 with a transmission function is connected between the signal lines of the loop transmission line 12, a unique terminal address is set to the fire detector 16, and voltage control is performed from the transmission section 100 to change the line voltage. Fires are monitored by transmitting signals (downstream signals) and from the fire detector 16 transmitting current response signals (upstream signals) that change the line current.

Furthermore, short circuit disconnection devices 18 known as short circuit isolators are connected along the loop transmission line 12 at predetermined line lengths and line positions.

A voltage monitoring circuit unit 104 is provided at the end of the loop transmission line 12 led into the receiver 10, and detects disconnection failures in the loop transmission line 12 based on the line voltage supplied from the transmission unit 100 to the loop transmission line 12. I'm monitoring it. Further, at the end of the loop transmission line 12, a termination switch 102 is provided to switch and connect the signal line at the end to the transmission section 100. In the normal monitoring state, the termination switch 102 is turned off, and the end of the loop transmission line 12 is turned off. It is separated from the transmission section 100.

If a disconnection 106 occurs in the middle of the loop transmission line 12 during operation , the voltage monitoring circuit unit 104 detects the disconnection because the termination voltage of the loop transmission line 12 is disconnected, turns on the termination switch 102, and closes the loop. A transmission section 100 is connected to the terminal end of the transmission path 12 .

Therefore, the terminal control signal (voltage control signal) from the transmission unit 100 is transmitted from the terminal side of the loop transmission line 12 to the location where the disconnection 106 occurs via the termination switch 102, and the loop transmission between the location where the disconnection 106 occurs and the loop transmission It becomes possible to send and receive signals to and from the fire detector 16 connected between the ends of the loop transmission line 12, and even if a disconnection fault occurs, fire monitoring by the fire detector 18 connected to the loop transmission line 12 is possible. No loss of functionality and high reliability.

If a short circuit occurs in the loop transmission line 12 during operation, the short circuit disconnection devices 18 located on both sides of the short circuit turn off the switch 62 to disconnect the short circuit from the loop transmission line 12. When the short circuit is disconnected by the short circuit disconnection device 18, the termination voltage of the loop transmission line 12 is disconnected as in the case of disconnection, so the voltage monitoring unit 104 detects the disconnection, turns on the termination switch 102, and stops the transmission. The terminal control signal from the section 100 is transmitted from the termination side of the loop transmission line 12 to the location where the disconnection 106 occurs via the termination switch 102, so that even if a short circuit failure occurs, the terminal control signal is not connected to the loop transmission line 12. The fire monitoring function of the fire detector 16 is not lost, and high reliability can be obtained.

Japanese Patent Application Publication No. 2008-004033 Japanese Patent Application Publication No. 2010-114632

However, in such conventional fire alarm equipment equipped with a loop transmission line, when a disconnection occurs in the loop transmission line 12, the receiver 10 performs loop transmission by monitoring the terminal voltage by the voltage monitoring circuit unit 104. Although it is known that a disconnection has occurred in the loop transmission line 12, it is not known where in the loop transmission line 12 the disconnection has occurred, and there is a problem in that it takes time and effort to repair the disconnection location.

Furthermore, even if the disconnection is restored by repair work, the signal voltage of the terminal control signal transmitted from the transmission unit 100 is applied to the terminal end of the loop transmission line 12 in the same way as at the time of the disconnection, and the transmission state of the loop transmission line 12 is maintained. Since there is no change, the receiver 10 cannot detect disconnection recovery.

Therefore, by periodically operating the recovery switch in the receiver, the termination switch 102 is turned off, and if the termination voltage is applied after recovery, it is determined that the termination switch 102 remains off and the disconnection has been recovered, and the termination voltage is not applied. If not, the termination switch 102 is turned on and it is determined that the disconnection continues, and manual operation is required to confirm that the disconnection has been restored, which poses a problem that takes time and effort.

The present invention makes it possible to reliably detect and notify the position of a disconnection when a disconnection occurs in a loop transmission line, and to automate disconnection recovery to return the transmission state of the loop transmission line to its original state when the disconnection is repaired. The purpose is to provide fire alarm equipment.

( Distributed system relay board)
One or more relay boards are connected to the receiver via a network line, and a terminal including a fire detector and a short-circuit disconnection device is connected to the loop transmission line connected to the relay board to monitor fires. A distributed system is configured that notifies the receiver when a fire is detected and outputs a fire alarm.
The relay panel is equipped with a transmission section that operates according to instructions from the transmission control section,
The transmission section of the relay board is
If the termination voltage of the loop transmission line is detected normally, normal transmission control is performed to monitor for fire by sending and receiving signals from the start end of the loop transmission line.
When the termination voltage of the loop transmission line is cut off, the disconnection is detected and the termination switch is turned on, and the signal is transmitted and received from the start end of the loop transmission line at each predetermined transmission cycle. and terminal transmission control, which sends and receives signals from the end of the loop transmission line, and transmission control in the event of a disconnection, which monitors for fire by alternately switching between
If the termination voltage of the loop line is normally detected during the start-end transmission control in the transmission control at the time of disconnection, disconnection recovery control is performed in which the termination switch is turned off to cancel the transmission control at the time of disconnection and switch to the transmission control at the time of normal transmission.

(Detection of disconnection position using relay panel)
When the transmission section of the repeater panel detects a disconnection in the loop transmission path, it detects the start-side terminal group of the terminals from which a response signal has been received in response to the signal sent by the start-end transmission control, and also transmits the signal by the end-end transmission control. detects the termination side terminal group of the terminal that received the response signal in response to the received signal, detects the position between the start side terminal group and the termination side terminal group as the disconnection position of the loop transmission path, and notifies the receiver. Make it known.

(Effects of the fire alarm equipment of the first invention)
The present invention provides a transmission control unit for a receiver in fire alarm equipment that monitors fire by connecting a terminal including a fire detector and a short circuit isolator to a loop transmission line connected to the receiver. A transmission section is provided that operates according to instructions from the operator, and if the terminal voltage of the loop transmission line is detected normally, the transmission section performs normal transmission control to monitor fire by transmitting and receiving signals from the starting end of the loop transmission line. If the termination voltage of the loop transmission line is cut off, switching between the start-end transmission control, which sends and receives signals from the start end of the loop transmission line, and the end-end transmission control, which sends and receives signals from the end of the loop transmission line, prevents a fire. Since the transmission control at the time of disconnection is performed to monitor the disconnection and the disconnection position is detected, when the loop transmission line is disconnected, for example, the start-end transmission control and the end-end transmission control, which are performed alternately at each predetermined transmission cycle, can be used to detect the disconnection position. The location of the wire breakage can be detected by detecting the starting terminal side and the end terminal side that have a signal response, and the wire breakage position is notified by the display of the receiver, etc., so that the necessary Repair work can proceed efficiently.

(Effects due to detection of disconnection position)
In addition, when detecting a disconnection of the loop transmission path, the transmission unit detects the start-side terminal group of the terminal from which the terminal response signal was received by the start-end transmission control, and also detects the start-side terminal group of the terminal from which the terminal response signal was received by the end-end transmission control. By detecting the termination side terminal group of the terminal, and detecting and reporting the disconnection position of the loop transmission path between the origination side terminal group and the termination side terminal group, the connection between the origination side terminal group and the termination side terminal group is It is possible to reliably detect the disconnection position of the loop transmission line.

(Effects of the fire alarm equipment of the second invention)
In another aspect of the present invention, in a fire alarm system that monitors fire by connecting a terminal including a fire detector and a short circuit disconnection device to a loop transmission path connected to the receiver, the transmission to the receiver is provided. A transmission unit is provided that operates according to instructions from the control unit, and when the terminal voltage of the loop transmission line is detected normally, the transmission unit performs normal transmission to monitor for fire by sending and receiving signals from the start end of the loop transmission line. When the termination voltage of the loop transmission line is cut off, it detects the disconnection and turns on the termination switch, and performs transmission control in the event of a disconnection to monitor for fire by transmitting and receiving signals from the start and end of the loop transmission line. During transmission control in the event of a disconnection, a voltage control signal in a predetermined voltage range greater than or equal to a predetermined reference voltage is transmitted from either the start end or the end end, and the voltage at the other end of the loop transmission path is compared with the predetermined reference voltage. , when the voltage on the other end becomes equal to or higher than the reference voltage, disconnection recovery of the loop transmission line is detected, and disconnection recovery control is performed by turning off the termination switch to cancel the disconnection transmission control and switch to normal transmission control. Therefore, when the loop transmission line is disconnected, if the voltage at both ends of the termination switch that is in the on state is monitored, the voltage at the transmission section and the voltage at the other end of the loop transmission line are either the same or the voltage at the other end. The voltage is low, but when the disconnection is repaired and restored, the voltage at the other end of the loop transmission line becomes higher than the voltage at the transmission part due to the signal transmitted from one end of the loop transmission line being applied. By detecting the change in the termination voltage due to a change in the condition of the loop transmission line called disconnection recovery, it is possible to cancel the disconnection transmission control by turning off the termination switch and switch to normal transmission control, which prevents human error in the receiver. When the disconnection is repaired, the transmission status of the loop transmission line changes from bidirectional transmission to the start and end of the loop transmission line to unidirectional transmission to the start of the loop transmission line, without requiring any manual operation. Recovery can be done automatically.

(Transmission from the other end)
Further, in the fire alarm equipment of the second invention, the transmission section connects the other end of the transmission section to the other end of the loop transmission line when the voltage at the other end becomes lower than the reference voltage during transmission control in the event of disconnection. Since the other end of the transmission section is connected to the other end of the loop transmission line, the other end of the transmission section is disconnected while the voltage on the other end is below the reference voltage or below the reference voltage. Thus, it is possible to continue supplying power to the equipment placed at the other end of the loop transmission path. Since there is no power outage, it is possible to monitor fires using detectors and retain detection data, while also monitoring disconnection recovery.

(Effect of transmission section)
The transmission section also converts the terminal control signal output from the transmission control section into a voltage control signal within a predetermined voltage range, and transmits the signal from the starting end of the loop transmission path, and also receives the voltage control signal within a predetermined current range from the starting end of the loop transmission path. converts the current response signal that changes into a terminal response signal and outputs it to the transmission control section, and furthermore, when a voltage fixing signal is input from the transmission control section, the voltage control signal to be sent to the start end of the loop transmission path is set to a predetermined voltage. a starting end transmission unit that converts the terminal control signal output from the transmission control unit into a voltage control signal within a predetermined voltage range and transmits it from the terminal end of the loop transmission line, and a predetermined voltage control signal received from the start end of the loop transmission line. It converts the current response signal that changes in the current range into a terminal response signal and outputs it to the transmission control section, and furthermore, when a voltage fixing signal is input from the transmission control section, a voltage control signal is sent to the terminal side of the loop transmission path. A termination transmission unit that fixes the voltage to a predetermined voltage, a termination switch provided between the termination transmission unit and the end of the loop transmission line, and a termination switch that compares the termination voltage of the loop transmission line with a predetermined reference voltage, and determines whether the termination voltage is the reference voltage. A termination voltage monitoring unit is installed that detects disconnection of the loop transmission line and turns on the termination switch to connect the termination side transmission unit to the end of the loop transmission line when the voltage drops below or below the reference voltage. Through the cooperation of the terminating section, terminating transmission section, terminating switch, and terminating voltage monitoring section, proper transmission control for the loop transmission line, transmission control in the event of a disconnection that alternately performs starting end transmission control and terminating transmission control, and disconnection recovery control are performed. be able to.

(Effect of fixed voltage in transmission section)
In addition, when the voltage fixing signal is input from the transmission control unit, the start-end transmission unit and the termination transmission unit fix the voltage control signal to the lower limit voltage of the predetermined voltage range. By effectively utilizing the lower limit voltage, it is possible to easily fix the output voltage for the loop transmission line.

(Effect of termination voltage monitoring section)
Further, the termination voltage monitoring section includes a comparator, inputs the termination voltage to one input of the comparator, inputs the transmission output voltage of the termination transmission section as a reference voltage to the other input of the comparator, and inputs the transmission output voltage of the termination transmission section as a reference voltage. The loop transmission line breakage is detected by the output of the comparator when the voltage drops below the reference voltage, and the termination switch is turned on to connect the termination side transmission section to the end of the loop transmission line. By comparing the termination voltage of the transmission path and the output voltage of the termination transmission section, the termination switch can be easily and appropriately turned on and off when detecting a disconnection or recovering from a disconnection.

(Effects of relay boards in distributed systems)
In addition, one or more relay boards are connected to the receiver via a network line, and a terminal including a fire detector and a short-circuit disconnection device is connected to a loop transmission line connected to the relay board to monitor fires. A distributed system is configured that notifies the receiver when a fire is detected at the relay board and outputs a fire alarm.The relay board is equipped with a transmission section that operates according to instructions from the transmission control section, and the transmission section If the terminal voltage of the transmission line is detected normally, the terminal response signal is received by sending a control signal from the starting end, and normal transmission control is performed to monitor the fire, and the loop transmission line terminal voltage is disconnected. Start-end transmission control detects a disconnection in the case of a loop transmission line, sends a terminal control signal from the start end of the loop transmission line, and receives a terminal response signal at each predetermined transmission cycle, and transmits a terminal control signal from the end side to the loop transmission line. The termination transmission control for transmitting and receiving terminal response signals is performed alternately to monitor fire. If the termination voltage of the loop line is detected normally during the transmission control for disconnection, it is normal. Since disconnection recovery control is performed to restore transmission control when the loop transmission line is disconnected, the relay panel of the distributed system detects changes in the termination voltage associated with disconnection recovery when the loop transmission line is disconnected, and turns off the termination switch to prevent disconnection. By canceling transmission control and switching to normal transmission control, disconnection recovery can be performed automatically without requiring any human operation on the receiver.

(Effects due to detection of disconnection position by relay board)
In addition, when the transmission section of the repeater board detects a disconnection in the loop transmission line, it detects the start-side terminal group of the terminals that have received a response signal to the signal sent by the start-end transmission control, and also controls the end-end transmission control. Detects the end-side terminal group of the terminal that received the response signal in response to the signal transmitted by , detects the location between the start-side terminal group and the end-side terminal group as the disconnection position of the loop transmission path, and notifies the receiver. Even if the repeater's loop transmission line is disconnected, the start and end terminal groups that respond to the signal can be detected by using the start and end transmission controls that are performed alternately. The location of the disconnection in the repeater board's loop transmission line can be detected by using the receiver's display, etc., making the necessary repair work more efficient. You can proceed well.

Explanatory diagram showing an overview of fire alarm equipment that monitors fires using loop transmission lines Block diagram showing details of the transmitter of the receiver and the terminal connected to the loop transmission Circuit block diagram showing an embodiment of the termination voltage monitoring unit Circuit block diagram showing an embodiment of a short circuit disconnection device Time chart showing signal waveforms of each part due to transmission control when the loop transmission path is normal Block diagram showing the operating state of the transmission section when a disconnection occurs in the loop transmission line Time chart showing signal waveforms of each part due to transmission control when a disconnection occurs in the loop transmission line Flowchart showing transmission control for loop transmission path An explanatory diagram showing an overview of a distributed fire alarm system in which a relay board is connected to a receiver via a communication network. Explanatory diagram showing conventional notification equipment using a loop transmission line

[Fire alarm equipment]
(Summary of fire alarm equipment)
FIG. 1 is an explanatory diagram showing an overview of fire alarm equipment that monitors fires using a loop transmission line. As shown in FIG. 1, for example, an R-type receiver 10 is installed in a manager's room on the first floor of a building where fire alarm equipment is installed, and a pair of signal lines 14a, For example, two lines of the loop transmission line 12 using 14b are drawn out.

A plurality of fire detectors 16 each having a transmission function and each having a unique address are connected to the loop transmission line 12 . Further, a short circuit disconnection device 18 known as a short circuit isolator is connected to the loop transmission line 12 between the fire detectors 16 and detects a short circuit in the loop transmission line 12 and disconnects it. Like No. 16, a unique address is set and it has a transmission function.

Here, the maximum number of addresses set for the terminal including the fire detector 16 and the short circuit disconnection device 18 connected to the loop transmission line 12 is, for example, 255, and the loop transmission line 12 has a maximum of 254 fire detectors 16. and a terminal including a short-circuit disconnection device 18 can be connected.

In addition, in FIG. 1, in order to make the explanation easier to understand, ten fire detectors 16 and four short-circuit disconnection devices 18 are connected, and the addresses of the fire detectors 16 and short-circuit disconnection devices 18 are set on the loop transmission line 12. A1, A2... A14 from the starting end side.

(Receiver overview)
The receiver 10 is provided with a main CPU 20 and a plurality of sub CPU boards 22-1, 22-2, and the sub CPU boards 22-1, 22-2 are provided with a sub CPU 24 and a transmission section 26. The main CPU 20 and sub CPU 24 are connected by a serial transfer bus 25 and mutually transmit and receive data.

The main CPU 20 is equipped with a display 27 with a touch panel using a liquid crystal display panel or the like, a display section 28 equipped with representative lights for fire, gas leak, and failure, LED indicator lights, etc., and various switches necessary for fire monitoring. An operating section 30, an acoustic alarm section 32 provided with a speaker, and a transmission section 34 are connected. Further, the main CPU 20 is provided with a fire alarm control section 38 as a function realized by executing a program.

The sub CPU 24 provided on the sub CPU boards 22-1 and 22-2 is provided with a transmission control unit 36 as a function realized by executing a program. The transmission control unit 36 performs transmission control to instruct the transmission unit 26 to send and receive signals to and from the loop transmission path 12 .

The transmission control by the transmission control unit 36 of this embodiment performs normal transmission control when the loop transmission line 12 is normal, performs disconnection transmission control when a disconnection of the loop transmission line 12 is detected, and further performs transmission control when the loop transmission line 12 is disconnected. When the 12 disconnections are repaired and restored, disconnection recovery control is performed. Note that details of various types of transmission control by the transmission control unit 36 will be clarified in a later explanation.

The transmission unit 26 converts the terminal control signal outputted from the sub-CPU 24, which varies between 0 and 5V, into a voltage control signal (voltage pulse signal) which varies within a predetermined voltage range, for example, a voltage range of 24V to 33V, under the transmission control of the transmission control unit 36. It is converted into a downlink signal and output to the loop transmission line 12 as a downlink signal.

On the other hand, the terminal response signal from the fire detector 16 and the short circuit disconnection device 18 to the receiver 10 causes a signal current to flow through the loop transmission line 12 at the timing of bit 1 of the transmission data, and a current response signal in the form of a so-called current pulse train rises. The signal is sent to the receiver 10 as a signal. Therefore, the transmission unit 26 converts the current response signal received from the loop transmission line 12 into a terminal response signal of 0 to 5V and outputs it to the sub CPU 24.

Fire monitoring control by the fire alarm control section 38 of the receiver 10 when the loop transmission line 12 is normal is as follows. During normal monitoring, the transmission control unit 36 of the sub CPU 24 instructs the transmission unit 26 to transmit a broadcast batch AD conversion signal including a batch AD conversion command at regular intervals T. The fire detector 16, which has received this batch AD-converted signal, converts the analog smoke concentration signal output from the smoke detection section into a digital smoke concentration signal by AD conversion, and holds the digital smoke concentration signal as detection data. Subsequently, the transmission control section 36 instructs the transmission section 26 to transmit a paging signal including a polling command that sequentially specifies terminal addresses.

When the fire detector 16 receives a call signal having an address that matches its own address, it transmits a response signal containing the smoke density data held at that time to the receiver 10.

In addition, the fire detector 16 is set with a smoke density threshold equivalent to type 1 sensitivity, for example, a smoke density threshold of 5.0%/m as a warning display threshold, and the detected smoke density data is equal to or higher than the warning display threshold. When the warning display threshold is exceeded, it is determined that a fire has occurred, and a fire interrupt signal is transmitted to the receiver 10.

When the transmission control unit 36 receives the fire interrupt signal via the transmission unit 26, it transmits a group search command signal to identify the group that includes the fire detector 16 that caused the fire alarm, and then transmits an intra-group search command signal. The address of the fire detector 16 that transmitted the fire alarm is specified, smoke density data is intensively collected, and is transmitted to the main CPU 20 via the serial transfer bus 25.

The fire alarm control unit 38 of the main CPU 20 compares the fire alarm smoke density data received from the sub CPU 24 with a predetermined fire alarm threshold corresponding to type 2 sensitivity, for example, a fire alarm threshold of 10%/m. If the value exceeds the fire alarm threshold or the fire alarm threshold, it is determined that there is a fire and fire alarm control is performed.

The fire alarm control by the fire alarm control unit 38 turns on the fire representative light on the display unit 28, causes the speaker of the acoustic alarm unit 32 to output a predetermined main acoustic alarm indicating the occurrence of a fire, and indicates on the display 27 that a fire has been detected. Fire alarm information including the fire occurrence location is displayed based on the sensor address, and furthermore, the alarm shifting section 34 outputs a fire alarm signal to the outside to perform predetermined alarm shifting control and the like.

[Transmission unit configuration and transmission control]
FIG. 2 is a block diagram showing an embodiment of the transmission section of the receiver together with terminals connected to the loop transmission path.

(Configuration at the start end of the transmission section)
As shown in FIG. 2, a loop transmission line 12 using signal lines 14a and 14b is led out from starting terminals L1 and LC1 provided in the receiver 10, and a terminal end of the loop transmission line 12 is provided in the receiver 10. It is connected to the terminal terminal L2, L C 2.

The transmission section 26 of the receiver 10 is provided with a start transmission section 40 and a termination transmission section 48 . The positive side, which is the transmission output side, of the start end transmission section 40 is connected to the start end terminal L1 via the start end switch 42 and the diode 46, which are turned on in the normal state. The start switch 42 is a semiconductor switch using an FET or the like.

A starting end voltage monitoring section 44 is provided for the starting end switch 42 . The voltage control signal VOUT1 of the start end transmission section 40 is input to the start end voltage monitoring section 44, and the start end voltage VS1 taken out from between the diode 46 and the start end terminal L1 is also input.

The starting end voltage monitoring unit 44 compares the voltage control signal VOUT1 and the starting end voltage VS1, and normally turns on the starting end switch 42 to connect the starting end side of the loop transmission line 12 to the starting end transmission unit 40, and the starting end terminal L1 , LC1 and the first short-circuit disconnection device 18-1 when a short circuit occurs in the loop transmission line 12, the start end switch 42 is turned off and the start end transmission section 40 is disconnected from the loop transmission line 12.

A terminal control signal E1 that changes at 0 to 5 VDC is output from the sub CPU 24 provided with the transmission control section 36 to the start end transmission section 40, and a terminal control signal E1 that changes at 0 to 5 V DC is output from the start end transmission section 40 to the sub CPU 24. A response signal E2 is output.

Further, a voltage fixing signal E3 is output from the sub CPU 24 provided with the transmission control section 36 to the start end transmission section 40. The starting end transmission unit 40 that receives the voltage fixing signal E3 fixes the voltage control signal VOUT1 output to the loop transmission line 12 to a predetermined voltage, for example, 24V DC, which is the lower limit of the voltage range of the voltage control signal that varies from 24V to 33V DC. Note that DC will be omitted in the following explanation.

Furthermore, when a short circuit in the loop transmission line 12 is detected and the start end switch 42 is turned off, the start end voltage monitoring unit 44 outputs a short circuit detection signal E4 to the sub CPU 24.

(Configuration of transmission section termination side)
The positive side, which is the transmission output side, of the termination transmission section 48 provided on the termination side of the transmission section 26 is connected to the termination terminal L2 via the termination switch 50 and the diode 54, which are normally turned on. A termination voltage monitoring section 52 is provided for the termination switch 50. The termination switch 50 is also a semiconductor switch using an FET or the like. The voltage control signal VOUT2 of the termination transmission section 48 is input to the termination voltage monitoring section 52, and the termination voltage VS2 taken out from between the diode 54 and the termination terminal L2 is also input.

The termination voltage monitoring unit 52 compares the voltage control signal VOUT2 and the termination voltage VS2, and normally turns off the termination switch 50 to disconnect the termination side of the loop transmission line 12 from the termination transmission unit 48, When a disconnection occurs, the termination voltage VS2 drops to 0V and is disconnected, so this is detected, the termination switch 50 is turned on, and the termination transmission section 48 is connected to the end of the loop transmission line 12.

A terminal control signal E1 varying from 0 to 5 V is output from the sub CPU 24 provided with the transmission control section 36 to the terminal transmission section 48, and a terminal response varying from 0 to 5 V is output from the terminal transmission section 48 to the sub CPU 24. A signal E5 is output.

Further, a voltage fixing signal E6 is outputted from the sub CPU 24 provided with the transmission control section 36 to the terminal transmission section 48. The termination transmission unit 48 that has received the voltage fixing signal E6 outputs the voltage control signal VOUT2 to the loop transmission line 12 at a voltage that is the lower limit of the voltage range of the voltage control signal that changes from 24V to 33V, similar to the start transmission unit 40. Fix it to 24V.

Furthermore, when a disconnection of the loop transmission line 12 is detected and the start end switch 42 is turned on, the termination end voltage monitoring section 52 outputs a disconnection detection signal E7 to the sub CPU 24.

(Terminal voltage monitoring section)
FIG. 3 is a circuit block diagram showing an embodiment of the termination voltage monitoring section of FIG. 1. As shown in FIG. 3, the termination voltage monitoring unit 52 includes a comparator 70, and a termination proportional voltage VS2a obtained by dividing the termination voltage VS2 of the loop transmission line 12 by resistors 76 and 78 is input to the negative input terminal of the comparator 70. A voltage VOUT2a obtained by dividing the voltage control signal VOUT2 of the termination transmission section 48 by resistors 72 and 74 is input to the positive input terminal of the comparator 70. The voltage division ratio of resistors 76 and 78 is set to be equal to the voltage division ratio of resistors 72 and 74. Further, the diode 54 functioning as a rectifying diode prevents the termination voltage VS2 from dropping due to the voltage control signal VOUT2 of the termination transmission section 48.

Here, in the normal state, the termination voltage VS2 changes in the range of 24V to 33V, and the voltage control signal VOUT2 is fixed at the reference voltage VREF = 24V, and there is a relationship of (VOUT2)≦(VS2), and it is proportional to this. Thus, the relationship (VOUT2a)≦(VS2a) is obtained. Furthermore, when the termination switch 50 is turned on, (VOUT2a)≦(VS2a) can be maintained.

The comparator 70 sets the comparison output to L level and turns off the termination switch 50 when (VOUT2a)≦(VS2a), and sets the comparison output to H level and turns on the termination switch 50 when (VOUT2a)>(VS2a). It also outputs a disconnection detection signal E7 that goes to H level.

[Short circuit disconnection device]
FIG. 4 is a circuit block diagram showing an embodiment of a short circuit disconnection device provided in a loop transmission line. As shown in FIG. 4, the short-circuit disconnection device 18 includes a transmission section 56, a control section 58, a voltage detection section 60, switch circuit sections 62-1, 62-2, and diodes 64-1 to 64-4. It operates by receiving power supply from the lines 14a and 14b or from a dedicated power supply line.

The voltage detection section 60 detects the voltage between the signal lines 14a and 14b, which are the terminal ends of the loop transmission line 12, and outputs it to the control section 58. When a short circuit occurs between the signal lines 14a and 14b at the terminal end of the loop transmission line 12, the voltage detected by the voltage detection section 60 drops to approximately 0V. At this time, the control section 58 turns off the switch circuit sections 62-1 and 62-2. Further, when the short circuit is restored, the voltage detected by the voltage detection section 60 is restored to the normal voltage. At this time, the control section 58 turns on the switch circuit sections 62-1 and 62-2.

When the transmission unit 56 receives the voltage control signal transmitted from the receiver 10, it performs control corresponding to the command included in the voltage control signal, and transmits a current response signal to the receiver 10. Transmission and reception of signals from the receiver 10 is normally performed from the starting end side, and when the wire is broken, it is performed from the terminating end side. Therefore, the transmission section 56 is used to transmit and receive signals from the starting end side and the terminating end side using diodes 64-1 to 64-4. We are making it possible for you to respond.

That is, an input/output circuit passing through the diode 64-1, the transmission section 56, and the diode 64-2 is used for signal transmission and reception from the start end side, and a diode 64-3, the transmission section 56, and the diode 64-2 are used for signal transmission and reception from the termination side. 4 input/output circuits are used.

The control unit 58 receives a batch AD conversion signal from the receiver 10 via the transmission unit 56, followed by a call signal in which the terminal address is sequentially specified, and when the control unit 58 receives the call signal in which the own address is specified, it returns to the normal state. Control is performed to transmit a response signal shown to the receiver 10.

Further, when the control unit 58 determines that the voltage detected by the voltage detection signal from the voltage detection unit 60 has decreased below a predetermined short circuit threshold, the control unit 58 instructs the transmission unit 56 to transmit an interrupt signal to the receiver 10, Since the receiver 10 searches for the address that received the interrupt signal and transmits the calling signal, the transmitter 56 is instructed to transmit a current response signal including stator information indicating detection of a short circuit to the receiver 10.

When the control unit 58 determines that the voltage detected by the voltage detection signal from the voltage detection unit 60 has recovered to a predetermined short-circuit recovery threshold or more, the control unit 58 instructs the transmission unit 56 to transmit an interrupt signal to the receiver 10, and performs reception. Since the machine 10 searches for the address that received the interrupt signal and transmits the calling signal, it instructs the transmission unit 56 to transmit a current response signal including stator information indicating detection of short circuit recovery to the receiver 10.

Note that the short-circuit disconnection device does not perform on/off control of the switch circuit units 62-1 and 62-2 based on the detected voltage, and the control unit 58 operates based on the terminal control signal received from the receiver 10 via the transmission unit 56. The switch circuit units 62-1 and 62-2 may be controlled to turn on and off as necessary, or the switch circuit units 62-1 and 62-2 may be turned on and off based on both the detected voltage and the terminal control signal. , it is also possible to perform off control.

[Transmission control]
Next, the transmission control using the loop transmission path by the transmission control section 36 and the transmission section 26 in FIG. 2 will be explained separately for normal times and disconnection times. Further, the detection function of the disconnection position by the transmission control unit 36 of this embodiment corresponds to the fire alarm equipment of the first invention, and the transmission control by the transmission control unit 36 of this embodiment at the time of disconnection and when recovering the disconnection is This corresponds to the fire alarm equipment of the second invention.

(Transmission control during normal operation)
FIG. 5 is a time chart showing signal waveforms of various parts due to transmission control when the loop transmission path is normal. FIG . ~A 14 ), FIG. 5(B) shows the voltage fixing signal E3 to the starting end transmission section 40, and FIG. 5(C) shows the voltage control signal VOUT1 output from the starting end transmission section 40 to the starting end of the loop transmission line 12. 5(D) shows the current response signal IIN1 received from the starting end of the loop transmission line 12 by the starting end transmission section 40, FIG. 5(E) shows the operating state of the starting end switch 42, and FIG. ) indicates the starting voltage VS1 input to the starting voltage monitoring unit 44, which becomes the signal waveform on the starting side.

On the other hand, as signal waveforms on the termination side, FIG. 5(G) shows the voltage fixing signal E6 to the termination transmission section 48, and FIG. 5(H) shows the voltage control signal output from the termination transmission section 48 to the termination of the loop transmission line 12. 5(I) shows the current response signal IIN2 received from the end of the loop transmission line 12 by the terminating transmission section 48, and FIG. 5(J) shows the operating state of the terminating switch 50. (K) shows the termination voltage VS2 input to the termination voltage monitoring section 52.

The transmission control unit 36 performs normal transmission control in which fire is monitored by transmitting and receiving signals from the starting end of the loop transmission line 12 during normal operation when the loop transmission line 14 is free of disconnection.

In normal transmission control by the transmission control unit 36, the start-end transmission control instructs the start-end transmission unit 40 and the end-end transmission unit 48 to transmit a signal from the start end side of the loop transmission path 12, and to receive a signal from a terminal from the start end side. I do.

In the start end transmission control, the start end switch 42 is on and the end switch 50 is off. As shown in FIG. 5(G), the transmission control unit 36 sets the voltage fixing signal E6 to the termination transmission unit 48 at H level, and the termination transmission unit 48 outputs the terminal control signal varying from 0 to 5V output from the sub CPU 24. The operation of converting E1 into the voltage control signal VOUT2 varying between 24V and 33V is prohibited, and the voltage control signal VOUT2 output from the termination transmission section 48 is fixed at 24V, as shown in FIG. 5( H ).

On the other hand, as shown in FIG. 5B, the transmission control section 36 sets the voltage fixing signal E3 to the start end transmission section 40 at L level, so that the start end transmission section 40 receives the terminal control signal E1 input from the sub CPU 24. It is converted into a voltage control signal VOUT1 varying in the range of 24V to 33V, and transmitted to the start end side of the loop transmission line 12 via the start end switch 42.

The voltage control signal VOUT1 transmitted from the start end transmission section 40 to the loop transmission line 12 is connected to the loop via the short-circuit disconnection devices 18-1 to 18-4 in which switch circuit sections 62-1 and 62-2 are all turned on. The signal is transmitted to the end of the transmission line 12, and the terminal voltage VS 2 of the loop transmission line 12 varies in the range of 24V to 33V.

The termination voltage monitoring unit 52 compares the fixed voltage of 24V of the voltage control signal VOUT2 output from the termination transmission unit 48 with the termination voltage VS2 of 24V to 33V applied between the termination terminals L2 and LC2 of the loop transmission line 12. By maintaining the relationship of VOUT2)≦(VS2), the off state of the termination switch 50 is maintained.

Here, as shown in FIG. 5A, the transmission control unit 36 sends the terminals indicated by numbers 1 to 14 following the broadcast batch AD conversion signal as the terminal control signal E1 at every predetermined transmission cycle T. A call signal specifying addresses A1 to A14 is sent sequentially, and when the fire detector 16 determines that the address matches its own address, it sends sensor data such as smoke concentration held by AD conversion as a current response signal IIN1. The current response signal IIN1 received by the start end transmission unit 40 is converted into a terminal response signal E2 of 0 to 5V and output to the sub CPU 24.

(Disconnection occurs)
FIG. 6 is a block diagram showing the operating state of the transmission section when a disconnection occurs in the loop transmission line. As shown in FIG. 6, for example, assume that a disconnection 90 occurs between the fire detector 16-5 and the fire detector 16-6. When the disconnection 90 occurs, the voltage control signal VOUT1 from the start end to the loop transmission line 12 on the termination side as seen from the location where the disconnection 90 occurs is no longer transmitted, and the termination voltage VS2 of the loop transmission line 12 drops to 0V and the voltage will not be obtained.

Therefore, since the termination voltage VS2 becomes 0V due to the occurrence of the disconnection 90, the termination voltage monitoring unit 52 has an input relationship of (VOUT2)>(VS2), and the output of the comparator 70 shown in FIG. The level changes from L level to H level, turns on the termination switch 50, and connects the output of the termination transmission section 48 to the termination side of the loop transmission line 12.

Further, the termination voltage monitoring section 52 outputs a disconnection detection signal E7 to the sub CPU 24, and the transmission control section 36 detects the disconnection of the loop transmission line 12 and starts transmission control at the time of disconnection. Furthermore, the transmission control unit 36 notifies the main CPU 20 shown in FIG. do.

(Transmission control at disconnection)
Figure 7 is a time chart showing the signal waveforms of various parts due to transmission control when a disconnection occurs in the loop transmission line, and Figures 7 (A) to (K) correspond to Figures 5 (A) to (K). ing.

When the transmission control unit 36 detects a break in the loop transmission line 12, the transmission control unit 36 performs a start end transmission control for transmitting and receiving signals from the start end of the loop transmission line 12 every transmission cycle T, and a termination switch 50 that is turned on due to the detection of the break in the loop. Termination transmission control for transmitting and receiving signals from the termination of the transmission line 12 is alternately switched to conduct disconnection transmission control for monitoring fire.

That is, the transmission cycle T from time t1 to t2 in FIG. 7 is the start-end transmission control, and the next transmission cycle T from time t2 to t3 is the end-end transmission control. Repeat.

(starting end transmission control)
The start-end transmission control from time t1 to t2 in FIG. 7 is the same as the start-end transmission control during normal operation shown in FIG. However, the voltage control signal VOUT1 transmitted from the start end transmission unit 40 to the start end of the loop transmission line 12 by the start end transmission control is applied to the short circuit disconnection device 18-1, in which the switch circuit units 62-1 and 62-2 are all turned on. 18-2 to the termination side of the loop transmission line 12, but the fire is not transmitted beyond the location where the disconnection 90 occurs, and is connected between the start end of the loop transmission line 12 and the disconnection 90. The sensors 16-1 to 16-5 transmit a current response signal IIN1, which is received by the start end transmission unit 40, converted into a terminal response signal E2, and output to the sub CPU 24.

In addition, when starting end transmission control is being performed, the voltage control signal VOUT2 input to the terminating voltage monitoring section 52 is a fixed voltage of 24V, and the terminating voltage VS2 is a fixed voltage of 24V lower than the voltage control signal VOUT2 by the voltage drop caused by the diode. Since the voltage is lower and the condition (VOUT2)>(VS2) is satisfied, the termination switch 50 is maintained on.

(Terminal transmission control)
In the termination transmission control from time t2 to t3 in FIG. 7, both the start end switch 42 and the end switch 50 are on. The transmission control unit 36 detecting the disconnection of the loop transmission line 12 sets the voltage fixing signal E3 to the start end transmission unit 40 to H level as shown in FIG. 7(B), and as shown in FIG. 7(C), the start end The voltage control signal VOUT1 output from the transmission section 40 is fixed at 24V.

On the other hand, as shown in FIG. 7(G), the transmission control section 36 sets the voltage fixing signal E6 to the termination transmission section 48 at L level, so that the termination transmission section 48 receives the terminal control signal E1 input from the sub CPU 24. It is converted into a voltage control signal VOUT2 varying in the range of 24V to 33V, and transmitted to the terminal end of the loop transmission line 12 via the termination switch 50.

The voltage control signal VOUT2 transmitted from the termination transmission section 48 to the loop transmission line 12 is connected to the loop via the short-circuit disconnection devices 18-4 and 18-3 in which switch circuit sections 62-1 and 62-2 are all turned on. Fire detectors 16-6 to 16- are transmitted to the starting end of the transmission line 12, but are not transmitted beyond the location where the disconnection 90 occurs, and are connected between the end of the loop transmission line 12 and the disconnection 90. 10 transmits a current response signal IIN2, which is received by the terminal transmission section 48, converted into a terminal response signal E5, and output to the sub CPU 24.

Furthermore, when termination transmission control is being performed, the voltage control signal VOUT2 input to the termination voltage monitoring section 52 is 24V to 33V, and the termination voltage VS2 is a voltage lower than 24V to 33V, which is reduced by the voltage drop due to the diode. , (VOUT2)>(VS2), the termination switch 50 is maintained on.

However, since the voltage control signal VOUT2 is accompanied by voltage fluctuations, there is a possibility that the condition (VOUT2)≦(VS2) is temporarily satisfied in the comparator 70 due to the voltage fluctuations. For this reason, when termination transmission control is being performed, the comparator 52 may not be used to determine disconnection recovery.

Furthermore, when termination transmission control is being performed, the voltage control signal VOUT1 input to the start-end voltage monitoring section 44 is 24V, and the start-end voltage VS1 is a voltage lower than 24V, which is reduced by the voltage drop due to the diode, and (VOUT1) >(VS1), the termination switch 50 is kept on.

In this way, since the other end side of the transmission control is a fixed value, the condition of voltage control signal (VOUT) ≦ transmission line end voltage (VS) is satisfied in the comparator 70 only when the disconnection is restored. It is preferable to monitor disconnection recovery at the other end.

(Detection of disconnection position)
The transmission control unit 36 that has detected the disconnection of the loop transmission line 12 detects the disconnection position based on the terminal response signal received during the start-end transmission control and the end-end transmission control, which are performed alternately every transmission cycle in the disconnection transmission control. Performs notification control.

As shown in FIG. 6, when a disconnection 90 occurs in the loop transmission line 12, the transmission control unit 36 uses the start-end transmission control to send the terminal addresses sent from the start-end transmission unit 40 to the loop transmission line 12 to a paging signal that sequentially specifies the terminal address. On the other hand, since terminal response signals are received from the fire detectors 16-1 to 16-5 and the short-circuit disconnection devices 18-1 and 18-2, these addresses A1 to A7 are detected as the starting terminal group.

The transmission control unit 36 also controls the fire detectors 16-6 to 16-10 and the short-circuit disconnection device 18 in response to a call signal that sequentially specifies the terminal address transmitted from the termination transmission unit 48 to the loop transmission line 12 by termination transmission control. Since the terminal response signals are received from -3 and 18-4, these addresses A8 to A14 are detected as a terminal group.

Subsequently, the terminal control unit 36 detects a connection between the fire sensor 16-5 at the last address A7 in the detected start-side terminal group and the fire sensor 16-6 at the start address A8 in the end-side terminal group. It is detected as the occurrence position of the disconnection 90 in the loop transmission line 12, and the main CPU 20 is notified and a loop transmission line node map showing the disconnection position is displayed on the display 27 for notification.

(Disconnection recovery control)
The transmission control unit 36 detects whether the starting end voltage VS1 of the loop transmission line 12 is normally detected when the ending voltage VS2 of the loop transmission line is normally detected during the starting end transmission control in the transmission control at the time of disconnection, or when the starting end voltage VS1 of the loop transmission line 12 is normally detected during the ending transmission control. If detected, disconnection recovery control is performed in which disconnection transmission control is canceled by turning off the terminal switch 50 and switched to normal transmission control.

When repair work is performed on the disconnection 90 of the loop transmission line 12 shown in FIG. As the disconnection 90 is repaired, the signal is transmitted to the end of the loop transmission line 12, and the terminal voltage VS2 changes from the fixed voltage of 24V due to the voltage control signal VOUT2 during the disconnection to a voltage of 24V to 33V due to the voltage control signal VOTU1.

Therefore, the voltage input to the termination voltage monitoring section 52 has the relationship (VOUT2)≦(VS2), and the output of the comparator 70 shown in FIG. 3 changes from the H level to the L level, and the termination switch 50 Turn off.

In addition, the disconnection detection signal E7 output from the termination voltage monitoring unit 52 to the sub CPU 24 also changes from H level to L level, and the transmission control unit 36 detects the recovery of the disconnection and performs the previous transmission control at the time of disconnection. After canceling the disconnection, disconnection recovery control is performed to switch to normal transmission control, that is, start-end transmission control, and automatically returns to normal transmission control. Further, the transmission control unit 36 notifies the main CPU 20 of the disconnection recovery, so that the disconnection failure alarm of the receiver 10 is automatically reset.

Although a wire breakage occurs even when the switch circuit sections 62-1 and 62-2 are turned off by the short-circuit disconnection device, the above-mentioned automatic wire breakage recovery is possible even when the wire breakage is restored due to short-circuit recovery.

[Transmission control operation]
FIG. 8 is a flowchart showing transmission control for the loop transmission path, which is the control operation by the transmission control section 36 shown in FIG.

As shown in FIG. 8, the transmission control unit 36 sets the normal transmission mode in step S1 when there is no disconnection in the loop transmission line 12. The normal transmission mode is a mode in which the start end switch 42 is turned on, the end switch 50 is turned off, and the voltage fixing signal E6 is output to the end transmission section 48.

Subsequently, the transmission control unit 36 performs start end transmission control as normal transmission control in step S2, and performs control to transmit a voltage control signal from the start end side of the loop transmission line 12 and receive a current response signal from the terminal.

When the transmission control unit 36 detects a disconnection of the loop transmission line 12 in step S3 during normal transmission control , the process proceeds to step S4 and sets a disconnection transmission mode. The transmission mode at the time of disconnection is a mode in which the voltage fixing signal E6 is outputted to the termination transmission section 48 in each transmission cycle with the start end switch 42 and the termination switch 50 turned on, and a mode in which the voltage fixation signal E3 is outputted to the beginning end transmission section 40. This is a mode that alternates between modes.

After setting the disconnection transmission mode, the transmission control unit 36 first performs starting end transmission control in which a voltage control signal is transmitted from the starting end side of the loop transmission line 12 and a current response signal is received in step S5, and during the starting end control, step If disconnection recovery is not detected in S6, the start end transmission control in Step S5 is continued until it is determined in Step S7 whether the transmission cycle has elapsed.

When the transmission control unit 36 determines the passage of the transmission cycle in step S7, the process proceeds to step S8, and performs termination transmission control in which the voltage control signal is transmitted from the termination side of the loop transmission line 12 and the current response signal is received, and in step S9, the transmission control unit 36 proceeds to step S8. The elapse of the transmission cycle is determined, and the process proceeds to step S10, where a disconnection position is detected.

Detection of the disconnection position in step S10 involves detecting the starting end terminal group that responded in the starting end transmission control in step S5 and the terminating end terminal group that responded in the terminating transmission control in step S8, and moving the disconnection position between them. Detected and notified.

When the transmission control unit 36 detects disconnection recovery in step S6 during the start end transmission control in step S5 during the disconnection transmission control in steps S4 to S10, the transmission control unit 36 returns to step S1, sets the normal transmission mode, and performs the process in step S2. By entering normal transmission control, disconnection recovery is automatically performed.

[Embodiment of distributed system composed of receivers and relay boards]
FIG. 9 is an explanatory diagram showing an outline of a distributed fire alarm system in which a relay board is connected to a receiver via a communication network.

If the facility to be monitored becomes large-scale, such as being divided into multiple locations, as shown in FIG. A communication connection is established between the receiver 10 and the relay board 94 via a network line 96 such as Ethernet (registered trademark).

The receiver 10 is the same as shown in FIG. 1, whereas the relay board 94 is the same as that shown in FIG. The other components are basically the same as the receiver 10.

A loop transmission line 12 is connected to the relay panel 94, and terminals such as a fire detector 16 and a short-circuit disconnection device 18, which have a transmission function and are set with a unique address, are connected to the loop transmission line 12.

The relay board 94 is provided with a transmission section similar to the receiver 10 in FIG. When the terminal voltage of the loop transmission line 12 is normally detected, the transmission section of the relay panel 94 performs normal transmission control to monitor fire by transmitting and receiving signals from the starting end of the loop transmission line.

Furthermore, when the termination voltage of the loop transmission line 12 is disconnected, the transmission section of the relay board 94 detects the disconnection and turns on the termination switch, and transmits the signal from the start end of the loop transmission line 12 at every predetermined transmission cycle. Transmission control in the event of a disconnection is performed to monitor for fire by alternately switching between start-end transmission control, which transmits and receives signals, and end-end transmission control, which transmits and receives signals from the end of the loop transmission line via a termination switch.

In addition, if the termination voltage of the loop transmission line 12 is normally detected during the start end transmission control in the transmission control at the time of disconnection, the transmission section of the relay panel 94 cancels the transmission control at the time of disconnection by turning off the termination switch. Performs disconnection recovery control that switches to normal transmission control.

Further, when detecting a disconnection in the loop transmission line 12, the transmission unit of the repeater board 94 detects the start-end terminal group from which a response signal has been received in response to the signal transmitted by the start-end transmission control, and also performs the end-end transmission control. The receiver 10 detects the termination side terminal group of the terminals from which the response signal has been received in response to the signal transmitted by the receiver 10. to be notified and announced.

[Modification of the present invention]
(restoration)
The short-circuit disconnection device may perform ON control of the switch circuit units 62-1 and 62-2 using the detected voltage only when receiving the restoration confirmation signal from the receiver.

(Switching between start-end transmission control and end-end transmission control when disconnected)
In the above embodiment, the start-end transmission control and the end-end transmission control are switched at every predetermined transmission cycle when a wire is disconnected, but the start-end transmission control and the end-end transmission control may be switched at different transmission cycles. When there is no fire, it is preferable that the start-end transmission control and the end-end transmission control have the same transmission cycle, but if a fire or a sign of fire is detected by a sensor or When a fire detection device such as a transmitter detects a fire, it is desirable to increase the communication frequency, so even if the frequency of transmission control on the side where a fire is detected is increased between the start-end transmission control and the end-end transmission control. good.

(Allow some margin for the reference voltage)
In the above embodiment, the voltage control signal VOUT2 is set to DC 24V, which is the lower limit of the voltage range, during transmission from the start end side during normal operation or disconnection, but it may be set to a voltage smaller than this. It may be set to a small voltage, for example, 20V, with a predetermined voltage margin in consideration of the voltage drop caused by the loop transmission line 12. Similarly, the voltage control signal VOUT1 may be set to a small voltage, for example, 20V, with a predetermined voltage margin in consideration of the voltage drop caused by the loop transmission line 12 during transmission from the terminal side in the event of a disconnection.

The above embodiment takes as an example a fire alarm system in which an R-type fire detector is connected via a loop transmission path from an R-type receiver, but a loop-type detector connected from a P-type receiver is used as an example. The same applies to fire alarm equipment in which an address is set on a line and an addressable fire detector with a transmission function is connected.

Furthermore, the present invention includes appropriate modifications without impairing its objects and advantages, and is not limited by the numerical values shown in the above embodiments.

10: Receiver 12: Loop transmission line 14a, 14b: Signal line 16, 16-1 to 16-10: Fire detector 18, 18-1 to 18-4: Short circuit disconnection device 20: Main CPU
22-1, 22-2: Sub CPU board 24: Sub CPU
26, 56: Transmission section 27: Display 28: Display section 30: Operation section 32: Sound alarm section 34: Transfer section 36: Transmission control section 38: Fire alarm control section 40: Start end Transmission section 42: Start end switch 44: Start end Voltage monitoring section 46, 54, 64-1 to 64-4 : Diode 48: Termination transmission section 50: Termination switch 52: Termination voltage monitoring section 58: Control section 60: Voltage detection section 62-1, 62-2: Switch circuit Section 70: Comparator

Claims (2)

In fire alarm equipment that monitors fire by connecting a terminal including a fire detector and short-circuit disconnection device to a loop transmission line connected to a receiver,
The receiver is provided with a transmission section that operates according to instructions from a transmission control section,
The transmission section of the receiver includes:
If the termination voltage of the loop transmission line is detected normally, performing normal transmission control to monitor fire by transmitting and receiving signals from the starting end of the loop transmission line;
When the termination voltage of the loop transmission line is cut off, switching between a start-end transmission control for transmitting and receiving signals from the start end of the loop transmission line and a termination transmission control for transmitting and receiving signals from the termination end of the loop transmission line; Performs transmission control in the event of wire breakage to monitor fire, detects the wire breakage position,
One or more relay boards are connected to the receiver via a network line, and a terminal including a fire detector and a short-circuit disconnection device is connected to a loop transmission line connected to the relay board to monitor fire, A distributed system is configured to notify the receiver and output a fire alarm when a fire is detected at the relay board,
The relay board is provided with a transmission unit that operates according to instructions from a transmission control unit,
The transmission section of the relay board is
If the termination voltage of the loop transmission line is detected normally, performing normal transmission control to monitor fire by transmitting and receiving signals from the starting end of the loop transmission line;
a start end transmission control for detecting a disconnection when a termination voltage of the loop transmission line is cut off and turning on a termination switch, and transmitting and receiving signals from the start end of the loop transmission line at every predetermined transmission cycle; Performing termination transmission control for transmitting and receiving signals from the termination of the loop transmission line via a switch, and disconnection transmission control for monitoring fire by alternately switching,
If the termination voltage of the loop line is normally detected during the start-end transmission control in the transmission control at the time of a disconnection, the termination switch is turned off to cancel the transmission control at the time of the disconnection and perform the disconnection recovery control to switch to the transmission control at the time of normal transmission. ,
Fire alarm equipment characterized by:
In the fire alarm equipment according to claim 1 ,
When the transmission unit of the relay board detects a disconnection of the loop transmission line, the transmission unit detects a start-side terminal group of the terminals from which a response signal has been received in response to the signal transmitted by the start-end transmission control, and Detecting a termination side terminal group of terminals from which a response signal has been received in response to a signal transmitted by the termination transmission control, and determining a disconnection position of the loop transmission path between the start side terminal group and the termination side terminal group. A fire alarm system characterized by detecting the fire alarm and notifying the receiver to issue an alarm.

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