JP2007280005A - Fire alarm system - Google Patents

Abstract

An object of the present invention is to improve the reliability of disconnection monitoring by setting a current threshold value corresponding to the connection state of an actual fire detector in a sensor line.
A disconnection monitoring unit of a receiver or repeater 12 detects the number x of response type fire detectors 14 connected to a sensor line by a connection number detection unit 74, and a first current calculation unit 76 detects the sensor. The current I2 (= x.multidot.) Is obtained by multiplying the minimum current Ia during monitoring of the line by the terminal current I1 flowing through the terminator connected to the sensor line and the detected number x of the response type fire detectors. Is) as a summed current (I1 + I2), and the maximum current Ib at the time of disconnection of the sensor line lower than the minimum current Ia at the time of monitoring by the second current calculation unit 78 is detected by the number of response type fire detectors 14 It is obtained as a current I2 (= x · Is) multiplied by the per-consumption current Is. The threshold value setting unit 80 sets the current threshold value Ith for disconnection detection so as to be between the monitoring minimum current Ia and the disconnection maximum current Ib.
[Selection] Figure 6

Description

The present invention relates to a fire alarm system for detecting a disconnection by monitoring a current of a sensor line drawn from a receiver or a repeater.

  Conventionally, monitoring of disconnection of a sensor line in a fire alarm facility in which an on / off type fire detector is connected to a sensor line drawn out from a receiver or a repeater, a termination resistor, a Zener diode or a capacitor at the end of the sensor line In this case, the current or voltage flowing in the sensor line is compared with a predetermined disconnection threshold value in the receiver or repeater disconnection detector to determine whether it is normal or disconnected.

When detecting the disconnection of the sensor line by the current value, the minimum current Ia at the time of monitoring obtained by adding the current consumption of the sensor to the termination current of the terminator as a design value and the detection lower than the minimum current Ia at the time of monitoring When the number of connected devices is the maximum number of connections, a fixed threshold value Ith is provided between the maximum current Ib at the time of disconnection obtained as a design value. If the monitoring current I exceeds the threshold value Ith, it is determined as normal and the threshold value Ith or less If it becomes, it is judged as a disconnection.
JP 2004-94314 A

  However, in such conventional disconnection monitoring, the difference between the minimum current Ia during monitoring and the maximum current Ib during disconnection (but Ia> Ib) obtained as a design value is small, and is fixedly set between them. In disconnection monitoring based on the current threshold Ith, there is a case in which it is erroneously determined as disconnection due to a change in the current of the sensor line due to noise, and there is a problem that noise resistance deteriorates due to a decrease in the S / N ratio.

  In addition, the maximum number of connections to the sensor line is determined by design, but the number of fire detectors connected to the sensor line in the actual fire alarm facility varies within the maximum number of connections, and was assumed at the time of design. When the difference between the number of sensors and the number of sensors actually connected becomes large, the fixed current is fixed between the minimum current Ia at the time of monitoring and the maximum current Ib at the time of disconnection obtained as a design value assuming a specific number of sensors. In the disconnection monitoring with the current threshold Ith set to, it is difficult to monitor the disconnection appropriately in terms of noise resistance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fire alarm system that improves the reliability of disconnection monitoring by setting an optimum current threshold corresponding to the number of connected actual fire detectors in a sensor line.

In the present invention, a response type fire sensor that responds to an upstream signal in response to a downstream signal from a receiver or a repeater is connected to a sensor line drawn from the receiver or the relay, and the receiver or the relay detects the response. In a fire alarm facility provided with a disconnection detection unit for detecting a disconnection by determining that the detection current of the instrument line has dropped below a predetermined current threshold Ith, in the receiver or relay,
A connection number detection unit for detecting the number of response type fire detectors connected to the sensor line;
The minimum current Ia during monitoring of the sensor line is the current I2 obtained by multiplying the terminal current I1 flowing through the terminator connected to the sensor line and the number of detected fire detectors x by the current consumption Is per unit (= x · Is) and a first current calculation unit obtained as an addition current (I1 + I2);
The second current obtained as the current I2 (= x · Is) obtained by multiplying the number of detected response fire detectors by the current consumption Is per sensor, the maximum current Ib at the time of disconnection of the sensor line lower than the monitoring minimum current Ia A calculation unit;
A threshold setting unit for setting the current threshold Ith of the disconnection detection unit so as to be between the minimum current Ia during monitoring and the maximum current Ib during disconnection;
Is provided.

In another embodiment of the present invention, a response type fire sensor that responds an upstream signal to a downstream signal from a receiver or a relay to a sensor line drawn from the receiver or the relay, and a fire detection Sometimes an on / off type fire detector that sends an alarm current to the sensor line is connected, and a disconnection is detected by determining that the detected current of the sensor line has fallen below a predetermined current threshold Ith to the receiver or relay. In a fire alarm facility with a disconnection detector, in the receiver or repeater,
A connection number detecting unit for detecting the number x of response type fire detectors connected to the sensor line;
The current I2 (= x) obtained by multiplying the minimum current Ia during monitoring of the sensor line by the terminal current I1 flowing through the terminator connected to the sensor line and the current consumption I per unit by the number of detected response type fire detectors. A first current calculation unit that is obtained as an addition current (I1 + I2) with Is);
The sensor current is obtained by multiplying the maximum current Ib at the time of disconnection of the sensor line lower than the minimum current Ia at the time of monitoring by multiplying the detected number x of the response type fire detector by the consumption current Is per unit, and the sensor. Addition current I3 with the current consumption Io per unit multiplied by the estimated number (yx) of on-off type detectors, which is the maximum number y of connected line detectors subtracted from the detected number x of response type fire detectors A second current calculation unit obtained as (= (y−x) Io);
A threshold setting unit for setting the current threshold Ith of the disconnection detection unit so as to be between the minimum current Ia during monitoring and the maximum current Ib during disconnection;
Is provided.

  Here, the threshold setting unit obtains an average current (Ia + Ib) / 2 of the monitoring minimum current Ia and the disconnection maximum current Ib, and sets it as the current threshold Ith of the disconnection detection unit.

In another embodiment of the present invention, a fire detector is connected to a sensor line drawn from a receiver or a repeater, and the detected current of the sensor line is below a predetermined current threshold value to the receiver or the repeater. In a fire alarm facility equipped with a disconnection detector that detects the disconnection and detects a disconnection, in the receiver or repeater,
A monitoring current detector for detecting an average monitoring current Iav flowing in the sensor line during monitoring;
A current calculation unit for obtaining a maximum current Ib at the time of disconnection of the sensor line as a current (Iav−I1) obtained by subtracting a termination current I1 flowing in a terminator connected to the sensor line from an average monitoring current Iav;
A threshold setting unit that sets the current threshold Ith of the disconnection detection unit so as to be between the average monitoring current Iav and the maximum current Ib during disconnection;
Is provided.

Here, the threshold setting unit obtains an average current (Iav + Ib) / 2 of the average monitoring current Iav and the maximum current Ib during disconnection, and sets it as the current threshold Ith of the disconnection detection unit.

  According to the present invention, the actual number of sensor connections connected to the sensor line is detected using the response function of the response type fire sensor, and the upper limit of the disconnection threshold setting range is determined based on the detected number of connections. Since the disconnection is determined by determining the monitoring minimum current Ia and the disconnection maximum current Ib which is the lower limit, and setting the current threshold Ith so as to be between them, there is a range in which the disconnection threshold is set by reducing the consumption current. Even if it becomes narrow, the setting range is obtained according to the actual sensor connection status, for example, by setting a current threshold at the center of the setting range, the S / N ratio is improved, high noise resistance is secured, and disconnection occurs. Monitoring reliability can be improved.

  Even if a response type fire sensor and an on / off type fire sensor are mixed in the same sensor line, the actual number of connected response type fire detectors is detected and turned on / off based on the detected number. Assuming the number of connected fire detectors, even if the range for setting the disconnection threshold becomes narrow due to reduced current consumption, the setting range is determined according to the actual sensor connection status. By setting the threshold value, it is possible to improve the S / N ratio, ensure high noise resistance, and improve the reliability of disconnection monitoring.

Furthermore, in another embodiment of the present invention, the current for determining the upper limit of the threshold setting range for disconnection monitoring is obtained as the average monitoring current of the sensing line, and the range for setting the disconnection threshold is narrowed by reducing current consumption. However, by obtaining the setting range according to the actual sensor connection status, for example, by setting the current threshold at the center of the range, the S / N ratio is improved, high noise resistance is ensured, and the reliability of disconnection monitoring Can be improved.

  FIG. 1 is a block diagram showing a configuration of a fire alarm facility according to the present embodiment. In FIG. 1, a plurality of repeaters 12 are connected to a transmission line 18 and a repeater control line 19 drawn from the receiver 10, and a sensor line 20 is drawn from the repeater 12, and a plurality of responses are respectively received. The type fire detectors 14-1 to 14-n are connected.

  FIG. 2 is a block diagram showing an embodiment of the receiver 10 in FIG. In FIG. 2, the receiver 10 is provided with a receiver CPU 100, and a transmission circuit 102, a power supply unit 104, a display unit 106, an operation unit 108, an acoustic alarm unit 110, and a transfer unit 112 are provided for the receiver CPU 100. Provided.

  The receiver CPU 100 has a fire monitoring function realized by program control, and sends a transmission synchronization command to the repeater 12 of FIG. 1 by a transmission line 18 in accordance with an instruction to the transmission circuit 102. A polling command is sent a predetermined number of times.

  When receiving the fire interrupt signal from the repeater 12, the receiver CPU 100 displays a fire alarm using the display unit 106, issues an acoustic alarm from the acoustic alarm unit 110, and from the transfer unit 112 as necessary. A transfer signal is output to control interlocking of smoke-proof doors and alarm bells as interlocking devices.

  FIG. 3 is a block diagram showing an embodiment of the repeater in this embodiment. In FIG. 3, the repeater 12 includes a transmission circuit 22, a repeater CPU 24, a power supply unit 26, a current detection circuit 28, a transmission circuit 30, and a response signal detection circuit 32. The relay CPU 24 is provided with a relay processing unit 34 and a disconnection monitoring unit 36 as functions realized by program control.

  Each time the relay processing unit 34 receives a transmission synchronization command from the receiver 10, the relay processing unit 34 drives the transmission circuit 30 to send the normal monitoring command to the sensor line 20. All response-type fire detectors 14-1 to 14-n transmit a command response upstream signal to the downstream signal of the normal monitoring command.

  The downstream signal transmitted from the repeater 12 to the sensor line 20 is a so-called voltage mode signal for changing the voltage of the sensor line. On the other hand, the upstream signals transmitted from the response type fire detectors 14-1 to 14-n are so-called current mode signals for changing the current flowing through the sensor line 20.

  In addition, when the relay processing unit 34 detects a fire in any of the response type fire detectors 14-1 to 14-n, a fire interrupt signal is transmitted to the sensor line 20, so that the fire interrupt A signal is received and a sensor address search command is transmitted, and the sensor address of the fire detector that responds is acquired.

  The transmission of the fire interrupt signal at the time of the alerting by the response type fire detector is performed continuously, for example, twice at regular time intervals, for example. In the relay processing unit 34, the fire interrupt signal is transmitted twice. When the sensor address, which is the search result of the sensor address search command by reception, matches, the fire is confirmed, and fire detection is notified to the receiver 10 by a fire interrupt signal (fire confirmation notification), and a fire alarm is performed.

  The disconnection monitoring unit 36 determines that the detection current I of the sensor line 20 has decreased below a predetermined current threshold Ith, detects disconnection, notifies the receiver 10 of disconnection detection, and outputs a fault alarm. In the present embodiment, as will be clarified later, the response type fire detectors 14-1 to 14- in which the current threshold Ith used in the disconnection monitoring unit 36 is connected to the detector line 20 are used. The number x of connected n is detected and set to an optimum value.

  FIG. 4 is a block diagram showing an embodiment of the response fire sensor 14 in the present embodiment. In FIG. 4, the response type fire detector 14 includes a nonpolar noise absorbing circuit 37 having a nonpolar circuit and a noise absorbing circuit, a 9 volt output constant voltage circuit 38, a 3 volt output constant voltage circuit 40, and a reset monitoring circuit. 42, a sensor CPU 44, an EEPROM 46 as a volatile memory, a pulse driving circuit 48, a temperature detecting element 50 such as a thermistor, a temperature detecting circuit 52, a transmission signal detecting circuit 54, and a response signal sending circuit 56.

  The EEPROM 46 provided in the sensor CPU 44 stores an address, and further stores type data indicating that the response type fire sensor 14 is a heat sensor. The reset monitoring circuit 42 is activated when the sensor line 20 is turned on. In the initialization process by reset start of the sensor CPU 44, various setting information including an address is expanded in the internal RAM from the EEPROM 46, and the sensor is controlled.

  The sensor CPU 44 is provided with a sensor response function realized by program control. The sensor response function receives a downstream signal consisting of a command from the repeater 12 and a response pulse, and is received at this time when the response pulse count value matches the self address. An uplink signal as a response signal corresponding to the command being transmitted is transmitted.

  For example, a downstream signal including a normal monitoring command from the repeater 12 is detected by the transmission signal detection circuit 54 and input to the sensor CPU 44. After the command content is decoded, the sensor response unit 64 counts the response pulse. The response signal is output to the response signal transmission circuit 56 at the idle timing immediately after the address matches the self address, and the command response uplink signal is transmitted by the current change of the sensor line.

  The pulse drive circuit 48 of the response type fire detector 14 receives a drive pulse at a constant time interval from the sensor CPU 44 to drive the thermistor as the temperature detection element 50, and the temperature detection circuit 52 detects the temperature at each detection timing. Is detected and read into the sensor CPU 44, a fire alarm is detected when a preset fire temperature is exceeded, and a fire interrupt signal is transmitted to the sensor line 20 using the transmission signal sending circuit 56.

  In the present embodiment, when detecting the fire alarm, the sensor CPU 44 transmits a fire interrupt signal continuously, for example, twice within the transmission interval of the normal monitoring command from the repeater 12. If normal monitoring commands are transmitted at intervals of 9 seconds, for example, the fire detector 14 continuously transmits fire interrupt signals at intervals of 3 seconds when a fire is triggered.

  For such a fire interrupt signal from the response type fire detector 14, the repeater 12 issues a sensor number search command to obtain the sensor number, and for example, it is detected by receiving the third fire interrupt signal. A fire is confirmed on the condition that the search results of the device numbers match, and the receiver 10 is notified of the occurrence of the fire.

  When a fire is determined for the three fire interrupt signals at the repeater 12, the repeater 12 transmits an alarm indicator light control command, and in response to this, the response-type fire detector 14 activates an operation indicator light (not shown). Light up).

  In the repeater 12, when a fire is confirmed in the first report, a sensor address search command is issued continuously at intervals of, for example, T3 = 6 seconds. Therefore, the response fire detection in the second report is performed. When the alarm is issued, a sensor address response signal is transmitted in response to the sensor address search command, thereby recognizing a fire alarm in the same sensor line 20 such as the second report and the third report on the repeater 12 side. be able to.

  In the response type fire detector 14 shown in FIG. 4, a heat detector using a temperature detecting element 50 such as a thermistor is taken as an example, but a scattered light type smoke detecting unit including a light emitting element and a light receiving element. Of course, it may be a response type fire detector equipped with.

  FIG. 5 is a time chart of a command transmission downlink signal and a command response uplink signal between the repeater 12 and the response fire detector 14 of the present embodiment. FIG. 5A shows a downstream signal for command transmission. When the steady voltage of the sensor line is 19 volts, for example, the signal is changed from 19 volts to 31 volts.

  The down signal for command transmission performed by the voltage change includes a start pulse 60, a reference pulse 62, commands 64 and 66, and a response pulse 68. In this embodiment, the maximum number of response-type fire detectors that can be connected to the sensor line 20 is, for example, 38, and therefore 38 response pulses 68 are transmitted following the command 66. The commands 64 and 66 are the same command, and the reliability is improved by sending two commands in succession.

  In the response type fire detectors 14-1 to 14-38, the response pulse 68 following the down signal command 66 is counted, and when the count value matches the preset self-address, the response pulse immediately thereafter is counted. An uplink signal of a command response due to a current change is transmitted at 68 idle timings. FIG. 5B shows a case where 38 response fire detectors connected to the sensor line receive a normal monitoring command as a batch command and send an upstream signal of the command response.

  As shown in response type fire detectors 14-1 to 14-38 at addresses 1 to 38 in FIG. 5C, the command response uplink signal is counted at the timing when the response pulse 68 is counted and coincides with each address. Each response type fire sensor transmits command response upstream signals 72-1 to 72-38, and the combined signal is transmitted to the sensor line as the upstream signal in FIG. 5B.

  For this reason, the repeater 12 can detect the number x of response-type fire detectors actually connected to the sensing line 20 by counting the number of pulses of the response upstream signal to the normal monitoring command. it can.

  FIG. 6 is an explanatory diagram of a first embodiment of disconnection monitoring performed by detecting the number of connected response type fire detectors by the disconnection monitoring unit 36 provided in the repeater 12. In FIG. 6A, a plurality of response-type fire detectors 14 are connected to the sensor line 20 drawn from the repeater 12 in a range not exceeding the maximum number of connected units, for example, 38 units. A termination resistor 15 is connected to the end of the.

  The repeater 12 is provided with a connection number detecting unit 74, a first current calculating unit 76, a second current calculating unit 78, and a threshold setting unit 80 as functions realized by program control by the repeater CPU 24 shown in FIG. It has been.

  The connection number detector 74 detects the number x of the response type fire detectors 14 connected to the sensor line 20. Specifically, it operates at the time of start-up of the fire alarm facility, at the time of periodic self-diagnosis, or at the initial setting, etc., and the connected number x of the response type fire detectors 14 is, for example, an upstream signal for the normal monitoring command shown in FIG. It is detected by counting the number of pulses.

The first current calculator 76 calculates the minimum current Ia during monitoring of the sensor line 20. The monitoring minimum current Ia detected by the first current calculator 76 is given by the following equation.

(Minimum current during monitoring) = (Termination current) + (Current consumption of sensor x Number of connected devices x)
Ia = I1 + Is × x (1)

  That is, the monitoring minimum current Ia calculated by the first current calculation unit 76 is equal to the termination current I1 flowing through the termination resistor 15 and the number of detected fire detectors 14 connected to the sensor line 20 x and 1 This is a current value obtained by adding a value obtained by multiplying the sensor consumption current Is per unit.

The second current calculator 78 calculates the maximum current Ib when the sensor line 20 is disconnected. The maximum current Ib at the time of disconnection is given by the following equation.

(Maximum current at disconnection) = (Current consumption of sensor x Number of connected units)
Ib = Is × x (2)

  That is, the maximum current Ib at the time of disconnection assumes a state in which the termination resistor 15 is disconnected due to disconnection, and is a current obtained by multiplying the sensor consumption current Is per response fire detector 14 by the detected number x. is there.

The threshold setting unit 80 detects disconnection so as to be between the monitoring minimum current Ia (upper limit value) and the disconnection maximum current Ib (lower limit value) obtained by the first current calculation unit 76 and the second current calculation unit 78. Current threshold Ith of the unit is set. In the present embodiment, the threshold current Ith is set by the following equation, for example.

(Threshold current) = {(Minimum current during monitoring) + (Maximum current during disconnection)} / 2
Ith = (Ia + Ib) / 2
= {(I1 + Is * x) + (Is * x)} / 2 (3)

  That is, the threshold current Ith in the equation (3) is set as an average current obtained by adding the monitoring minimum current Ia and the disconnection maximum current Ib and dividing by two.

  FIG. 6B is an explanatory diagram for setting a current threshold value for disconnection monitoring in the first embodiment of FIG. In FIG. 6B, the monitoring minimum current Ia obtained by the first current calculation unit 76 gives the upper limit value of the threshold setting range 82, and the disconnection maximum current Ib obtained by the second current calculation unit 78 is a threshold setting. A lower limit value of the range 82 is given.

  For this threshold setting range 82, a current threshold Ith for disconnection monitoring is set at the center of Ia and Ib by equation (3). Note that Ic is the current value of the upstream signal output in the current mode from the response fire detector shown in FIG.

  As described above, in the first embodiment, the number x of response-type fire detectors 14 actually connected to the sensor line 20 is detected and monitoring is performed as an upper limit value for determining the threshold setting range 82. The minimum current Ia and the maximum current Ib at the time of disconnection are obtained, and compared with the setting of the current threshold for disconnection monitoring based on the design parameters based on the maximum number of sensors connected to the conventional sensor line 20 and the like. The current threshold value Ith for optimal disconnection monitoring based on the number of connected sensors can be set, and the current threshold value Ith has a sufficient difference from the minimum current value Ia during monitoring even when noise is added in the steady monitoring state. Therefore, it is possible to reliably avoid a situation where the monitoring current falls below the current threshold value Ith due to fluctuations in the monitoring current due to noise, and the disconnection is erroneously detected, improving the noise resistance and improving the reliability of the disconnection monitoring. In That.

  FIG. 7A is an explanatory diagram of a second embodiment of disconnection monitoring by the disconnection monitoring unit provided in the repeater 12. In the second embodiment, the response type fire sensor 14 is turned on and off in the sensor line 20. Disconnection monitoring is performed when the fire detectors 16 are connected together.

  In FIG. 7A, x response fire sensors 14 are connected to the sensor line 20 drawn from the repeater 12, and an on / off type fire sensor 16 is also connected. Here, if the maximum number of fire detectors that can be connected to the sensor line 20 is y, the number x of connected response fire detectors 14 can be detected by the connection number detector 84 provided in the repeater 12.

  On the other hand, the number of connections of the on / off type fire detector 16 cannot be detected, but the maximum number y of sensors that can be connected to the sensor line 20 is fixedly determined. Finds the number (y-x) obtained by subtracting the detection number x of the response type fire detector 14 from the maximum number y of connected detectors as the predicted number of on / off type fire detectors 16, and sets the current threshold Ith used for disconnection monitoring. Do.

  The repeater 12 is provided with a connection number detection unit 84, a first current calculation unit 85, a second current calculation unit 86, and a threshold setting unit 88 as functions realized by program control by the repeater CPU 24 shown in FIG. It has been.

  The connection number detection unit 84 detects the number x of the response type fire detectors 14 connected to the sensor line 20. Specifically, it operates at the time of start-up of the fire alarm facility, at the time of periodic self-diagnosis, or at the initial setting, etc., and the connected number x of the response type fire detectors 14 is, for example, an upstream signal for the normal monitoring command shown in FIG. It is detected by counting the number of pulses.

The first current calculation unit 85 obtains the monitoring minimum current Ia of the sensor line 20 by the following equation.

(Minimum current during monitoring) = (Termination current) + (Current consumption of sensor x Number of detection units x)
Ia = I1 + Is × x (4)

  That is, the monitoring minimum current Ia is a value obtained by adding the current obtained by multiplying the terminal consumption current Is per one of the response type fire detectors 14 to the terminal current I1 flowing through the terminal resistor 15 by the detection number x. The monitoring minimum current Ia determines the upper limit of the threshold setting range 90 as shown in FIG.

The second current calculation unit 86 obtains the maximum current Ib at the time of disconnection of the sensor line 20 by the following equation.

(Maximum current at disconnection) = {(Response-type fire detector current consumption) x (Number of connected units)}
+ {(ON / OFF sensor current consumption) x (Maximum number of connected sensors-Number of detection units)}
Ib = (Is × x) + {Is × (y−x)} (5)

  That is, the disconnection maximum current Ib is a value obtained by adding the total current consumption of x response fire detectors 14 and the total current consumption of predicted (yx) on-off fire detectors 16 as shown in FIG. A lower limit of the threshold setting range 90 of (B) is given.

The threshold setting unit 88 sets the current threshold Ith of the disconnection detection unit so that it is between the monitoring minimum current Ia and the disconnection maximum current Ib obtained by the first current calculation unit 84 and the second current calculation unit 86. . In the present embodiment, the threshold current Ith is set by the following equation, for example.

(Threshold current) = {(Minimum current during monitoring) + (Maximum current during disconnection)} / 2
Ith = (Ia + Ib) / 2
= {(I1 + Is × x) + (Is × x) + {Is × (y−x)} / 2 (6)

  That is, the average current obtained by adding the monitoring minimum current Ia and the disconnection maximum current Ib and dividing by 2 by the equation (6) is set as the current threshold Ith.

  FIG. 7B is an explanatory diagram of a setting state of the current threshold Ith used for disconnection monitoring in the second embodiment of FIG. In FIG. 7B, the monitoring minimum current Ia that determines the upper limit of the threshold setting range 90 is detected by the response-type fire sensor 14 that is actually connected to the sensor line 20 as shown in the equation (4). It is calculated based on the number x.

  Further, the disconnection maximum current Ib that gives the lower limit of the threshold setting range 90 is the sensor number connected to the sensor line 20 and the detected number x of the response-type fire sensor 14 actually detected as in the above equation (5). It is calculated based on the predicted number of connected on-off type fire detectors (yx) estimated from the maximum number of connections y.

  Therefore, setting of a current threshold for conventional disconnection monitoring based on design parameters performed by fixedly determining the number of connected response type fire detectors 14 and the number of connected on / off type fire detectors 16 under specific conditions. Compared with the second embodiment, the second embodiment is optimal under conditions that are sufficiently approximate to the number of response type fire sensors 14 and the number of on / off type fire sensors 16 actually connected to the sensor line 20. A current threshold value Ith for monitoring disconnection can be set.

  Since the number of on / off type fire detectors 16 connected to the actual sensor line 20 is relatively smaller than the number of response type fire detectors 14, the maximum current at the time of disconnection by the unknown number of on / off type fire detectors 16 is shown. The variation of Ib is suppressed to the minimum, and therefore, it is possible to set an appropriate current threshold value Ith in accordance with the actual connection condition.

  FIG. 8 is an explanatory diagram of a third embodiment of disconnection monitoring performed by detecting the monitoring current of the sensor line by the disconnection monitoring unit provided in the repeater 12. In FIG. 8 (A), the response type fire sensor 14 and the on / off type fire sensor 16 are connected to the sensor line 20 drawn from the repeater 12 within the range of the maximum number of sensor connections, for example. A termination resistor 15 is connected to the end of the line 20.

  The repeater 12 is provided with a monitoring current detection unit 92, a current calculation unit 94, and a threshold setting unit 96 as functions realized by program control of the repeater CPU 24 shown in FIG. The monitoring current detector 92 detects the average monitoring current Iav flowing through the sensor line 20. This average monitoring current Iav gives the upper limit of the threshold setting range 98 as shown in FIG.

The current calculation unit 94 calculates the maximum current when the sensor line 20 is disconnected by the following equation.

(Maximum current at disconnection) = (Average monitoring current)-(Termination current)
Ib = Iav−I1 (7)

  The disconnection maximum current Ib is a current obtained by subtracting the termination current I1 flowing through the termination resistor 15 from the average monitoring current Iav.

The threshold setting unit 96 sets the current threshold Ith of the disconnection detection unit so as to be between the average monitoring current Iav obtained by the monitoring current detection unit 92 and the current calculation unit 94 and the maximum current Ib at the time of the disconnection. Set by.

(Threshold current) = {(Average monitoring current) + (Maximum current at disconnection)) / 2
Ith = (Iav + Ib) / 2
= {(Iax) + (Iav-I1)} / 2 (8)

  The current threshold Ith set by the equation (8) is set as an average current obtained by adding the average monitoring current Iav and the disconnection maximum current Ib and dividing by two.

  FIG. 8B shows a setting state of the current threshold Ith in the third embodiment of FIG. In FIG. 8B, the upper limit of the threshold setting range 98 is given by the average monitoring current Iav of the sensor line 20 detected by the monitoring current detector 92. On the other hand, the lower limit of the threshold setting range 98 is given by the disconnection maximum current Ib calculated by the current calculation unit 94.

  The current threshold value Ith for disconnection monitoring is set at the center position obtained by adding the upper limit current Iav and the lower limit current Ib and dividing by two to ensure erroneous detection of disconnection when noise is added to the sensor line. Can be prevented.

  The advantage of the third embodiment of FIG. 8 is that an optimum current threshold Ith for disconnection monitoring can be set without depending on the type of the fire sensor connected to the sensor line 20. That is, in FIG. 8A, the response type fire sensor 14 and the on / off type fire sensor 16 are mixedly connected to the sensor line, but even if only the response type fire sensor 14 is connected. Alternatively, only the on / off type fire sensor 16 may be connected.

  FIG. 9 is an explanatory diagram of an embodiment in which the disconnection of the sensor line is monitored by the receiver. The fire alarm facility in FIG. 9 is a relatively small-scale facility, and a response-type fire detector 14 is connected to a sensor line 20 drawn from the receiver 10. 15 is connected.

  The receiver 10 has the function for monitoring disconnection shown in the first embodiment of FIG. 6, the second embodiment of FIG. 7 or the third embodiment of FIG. 8, for example, a program executed by the receiver CPU 100 shown in FIG. Based on the actual number of fire detectors connected to the sensor line 20, the optimum current threshold Ith for disconnection monitoring is set, and the S / N ratio is improved to improve disconnection monitoring. Reliability can be increased.

  In the above embodiment, the pulse transmission system is taken as an example of a response type fire detector. However, in addition to this, a message based on a command response from the fire detector side is received for a message from a receiver or a repeater. The same applies to a fire alarm facility of a data transmission system that responds.

The present invention is not limited to the above-described embodiments, includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited by the numerical values shown in the above-described embodiments.

The block diagram which showed embodiment of the fire alarm equipment of this embodiment Block diagram illustrating an embodiment of a receiver Block diagram showing an embodiment of a repeater Block diagram showing an embodiment of a fire detector Time chart of monitoring command transmission timing from repeater Explanatory drawing of 1st Embodiment of the disconnection monitoring performed by detecting the connection number of response type fire detectors Explanatory drawing of 2nd Embodiment of disconnection monitoring when a response type fire sensor and an on-off type fire sensor are mixed and connected to the sensor line Explanatory drawing of 3rd Embodiment of the disconnection monitoring performed by detecting the monitoring current of a sensor circuit | line Explanatory drawing of embodiment which monitors the disconnection of a sensor circuit | line with a receiver

Explanation of symbols

10: Receiver 12, 12-1, 12-2: Repeater 14, 14-1 to 14-n: Response type fire sensor 16: On-off type fire sensor 18: Transmission line 19: Repeater control line 20: Sensor lines 22, 102: Transmission circuit 24: Repeater CPU
25, 26: power supply unit 28: current detection circuit 30: transmission circuit 32: response signal detection circuit 37: nonpolar noise absorption circuit 38, 40: constant voltage circuit 44, 46: constant voltage circuit 42: reset monitoring circuit 44: sensing CPU
46: EEPROM
47: Type data 48: Pulse drive circuit 50: Temperature detection element 52: Temperature detection circuit 54: Transmission signal detection circuit 56: Response signal transmission circuit 60: Start pulse 62: Reference pulse 64, 66: Command 68: Response pulse 72 -1 to 72-38: Command response uplink signals 74, 84: Connection number detection units 76, 85: First current calculation units 78, 86: Second current calculation units 80, 88, 96: Threshold setting units 82, 90, 98: Threshold setting range 92: Monitor current detection unit 94: Current calculation unit 100: Receiver CPU
106: Display unit 108: Operation unit 110: Acoustic alarm unit 112: Transfer unit

Claims (5)

A response type fire sensor that responds to an upstream signal with respect to a downstream signal from the receiver or relay is connected to a sensor line drawn from the receiver or the relay, and the sensor is connected to the receiver or the relay. In the fire alarm facility provided with a disconnection monitoring unit for detecting disconnection by determining that the detected current of the line has dropped below a predetermined current threshold,
In the receiver or repeater,
A connection number detector for detecting the number of response type fire detectors connected to the sensor line;
The minimum current during monitoring of the sensor line is the sum of the terminal current flowing through the terminator connected to the sensor line and the current obtained by multiplying the number of detected response fire detectors by the current consumption per unit. A first current calculation unit obtained as:
A second current calculation unit for obtaining a maximum current at the time of disconnection of the sensor line lower than a minimum current at the time of monitoring as a current obtained by multiplying the number of detected response fire detectors by a current consumption per unit;
A threshold setting unit for setting a current threshold of the disconnection detection unit so as to be between the minimum current at the time of monitoring and the maximum current at the time of disconnection;
Fire alarm equipment characterized by the provision of
A response-type fire detector that responds to an upstream signal from a downstream signal from the receiver or relay device to a sensor circuit drawn from a receiver or a relay device, and an alarm current to the sensor circuit when a fire is detected. A fire alarm in which an on / off type fire sensor is connected, and a disconnection detection unit is provided for detecting a disconnection by determining that the detection current of the sensor line has dropped below a predetermined current threshold to the receiver or repeater. In the equipment,
In the receiver or repeater,
A connection number detector for detecting the number of response type fire detectors connected to the sensor line;
The minimum current during monitoring of the sensor line is the sum of the terminal current flowing through the terminator connected to the sensor line and the current obtained by multiplying the number of detected response fire detectors by the current consumption per unit. A first current calculation unit obtained as:
The maximum current at the time of disconnection of the sensor line lower than the minimum current at the time of monitoring, the current obtained by multiplying the number of detected response type fire detectors by the current consumption per unit, and the maximum number of sensor connections of the sensor line A second current calculation unit for obtaining an addition current with a current obtained by multiplying the predicted number of the on-off type detectors obtained by subtracting the number of detected response type fire detectors from the current consumption per unit,
A threshold setting unit for setting a current threshold of the disconnection detection unit so as to be between the minimum current at the time of monitoring and the maximum current at the time of disconnection;
Fire alarm equipment characterized by the provision of
The fire alarm system according to claim 1 or 2, wherein the threshold value setting unit obtains an average current of the monitoring minimum current and the disconnection maximum current and sets the current threshold value of the disconnection detection unit. Fire alarm equipment.
A fire detector is connected to the sensor line drawn from the receiver or the repeater, and it is determined that the detection current of the sensor line has dropped below a predetermined current threshold to the receiver or the repeater. In fire alarm equipment with a disconnection detector to detect,
In the receiver or repeater,
A monitoring current detector for detecting an average monitoring current flowing through the sensor line during monitoring;
A current calculation unit for obtaining a maximum current at the time of disconnection of the sensor line as a current obtained by subtracting a termination current flowing in a terminator connected to the sensor line from the average monitoring current;
A threshold setting unit for setting a current threshold of the disconnection detection unit so as to be between the average monitoring current and the maximum current at the time of disconnection;
Fire alarm equipment characterized by the provision of
  5. The fire alarm system according to claim 4, wherein the threshold value setting unit obtains an average current of the average monitoring current and the maximum current at the time of disconnection, and sets the average current of the disconnection detection unit. Facility.

Images