JP2003217045A - Sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor capable of preventing a malfunction of a receiver and the sensor. <P>SOLUTION: This sensor is a sensor connected with the receiver via a line (e.g. a fire sensor) and is provided with a current limiting means 101 limiting current of the sensor flowing in the line for preventing the malfunction of the receiver due to the large current flowing in the line, and a switching means 102 switching a current limit quantity on the current limiting means 101 in accordance with electric energy required for a process of the sensor. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

The present invention relates to a sensor connected to a receiver via a line.

[0002]

2. Description of the Related Art FIG. 1 is a system having a receiver 1 and at least one detector (for example, a fire detector) S _{1 to} S _n connected in parallel to the receiver 1 via a line. It is a figure which shows the structural example of what is called a P-type system.

In the example of FIG. 1, the receiver 1 has a power source 2 and
District relay RL, a predetermined delay circuit (delay means) 3,
A fire relay RF is provided. In FIG. 1, reference characters T and T ₀ are terminals to which lines (lines) are connected.

FIG. 2 is a diagram showing a configuration example of _one sensor (for example, S ₁ ) used in the system of FIG. Referring to FIG. 2, the detector includes a light emitting circuit 11
A light receiving circuit 12 and a processing circuit (eg, CPU) 13
A non-volatile memory 14, a first constant voltage circuit 15,
Second constant voltage circuit 17, reporting circuit 18, transmission circuit 1
9 and capacitors C1, C2 and C3.

FIG. 3 shows a system as shown in FIG.
Further, as shown in FIG. 4, a tester 20 is provided between the terminals T and T ₀ .
FIG. 4 is a diagram showing a state in which communication is performed (testing is performed) between the tester 20 and the sensor by connecting the test equipment 20 and the sensor. 3 (a) is a diagram showing line voltage (line voltage), FIG. 3 (b) is a diagram showing voltage at a point in the sensor, and FIG. 3 (c) is a diagram. FIG. 3 is a diagram showing a line current (line current), FIG. 3 (d) is a diagram showing an operation of the district relay RL in the receiver 1 when the line current is large, and FIG. It is a figure which shows operation | movement of the district relay RL in the receiver 1 when line current is small.

Communication (test) between the tester 20 and the sensor is performed during the communication period as shown in FIG. 3 (a).
This is done by applying a communication pulse (line voltage (voltage between terminals T and T ₀ ) of up to 10 V) from the tester 20 to the sensor. Communication (test) between tester 20 and sensor
Before the test is performed, the sensor is connected to the receiver 1 and the line voltage (line voltage (voltage between terminals T and T ₀ ) is 24 V, but communication between the tester 20 and the sensor ( When the test is performed (during the communication period), the line voltage (line voltage (voltage between the terminals T and T ₀ ) decreases to 10 V, so the capacitor C1 in the sensor is connected to the processing circuit 13. In order to properly perform the predetermined process, the discharge is performed as shown by an arrow Q1 in Fig. 2. As a result, the voltage at the point a in the sensor is changed from the tester 20 to the sensor as shown in Fig. 3 (b). Decreases until the communication (test) between the tester 20 and the sensor is completed, that is, during the communication period, and when the communication (test) between the tester 20 and the sensor is completed, that is, the communication period When the line ends, the line voltage (line voltage) is originally 2
At 4V, the capacitor C1 in the sensor charges as shown by arrow Q2 in FIG. That is, current flows into the sensor. When the current flows into the sensor, the line voltage (line voltage) drops below 24V as shown in FIG. 3 (a) (it drops to the level indicated by the broken line in FIG. 3 (a)). In particular, the line voltage (line voltage) decreases as the number of sensors connected in parallel between the terminals T and T ₀ , that is, the number _n of S _{1 to} S _n increases. On the other hand, the line current (line current) increases due to the current flowing into the sensor. The line current (line current) increases as the number of sensors connected in parallel between the terminals T and T ₀ , that is, the number _n of S _{1 to} S _n increases. In FIG. 3C, the line current (line current), which is the sum of the currents flowing in the respective sensors S _{1 to} S _n , increases as the number n of the sensors S _{1 to} S _n connected increases. As shown by the broken line in c), the state is shown in which it becomes larger (increases) than the regional relay opening current value (for example, 2.5 mA).

When the number _n of connected sensors S _{1 to} S _n is small and the line current (line current) is smaller than the local relay opening current value (for example, 2.5 mA), as shown in FIG. The district relay RL returns from ON to OFF when the communication between the tester 20 and the sensor ends (when the communication period shown in FIG. 3A ends) (that is, the receiver 1 operates normally). Operate).

On the other hand, the number of connections _n of the sensors S _{1 to} S _n is n.
When the line current (line current) becomes larger than the district relay open current value (for example, 2.5 mA) as shown in FIG. 3 (c), the district relay RL becomes as shown in FIG. 3 (d). , And remains in the ON state, and the alarm relay RF of the receiver 1 issues an alarm (the receiver 1 malfunctions).

FIGS. 5A and 5B are respectively shown in FIG.
It is a figure which shows operation | movement of the receiver 1 shown to (d) and (e) in detail.

[0010] That is, referring to FIG. 5 (a), sensor S ₁ to S _n of the connection number n is large, the line current (the line current)
Is larger than the district relay open current value (for example, 2.5 mA), in the receiver 1, the district relay RL
Remains ON even after the delay time elapses, and the alarm relay RF issues an alarm (the receiver 1 malfunctions).

On the other hand, referring to FIG. 5B, the sensor S
_{When the} number _n of connections _{1 to} Sn is small and the line current (line current) is smaller than the area relay open current value (for example, 2.5 mA), in the receiver 1, the area relay RL includes the tester 20 and the sensor. When the communication with the
When the communication period shown in (a) ends), ON to OFF
Return to. That is, it returns from ON to OFF before the delay time elapses. As a result, the alarm relay RF of the receiver 1 will not erroneously issue an alarm.

As described above, in the case of the receiver 1 using the relay, the number n of the sensors S _{1 to} S _n connected to the receiver 1 is n.
Is increased, the line current (line current), which is the sum of the currents flowing in the sensor, is increased, causing a problem that the relay of the receiver 1 malfunctions.

[0013]

In order to solve the above-mentioned problems that occur when a relay is used for the receiver 1, it is conceivable to configure the sensor as shown in FIG. That is, in the configuration of FIG. 6, the sensor is further provided with a current limiting circuit 16 in order to reduce the current of one sensor. In FIG. 6, the same parts as those in FIG. 2 are designated by the same reference numerals.

FIG. 7 shows an example of the current limiting circuit 16 used in the sensor of FIG. 6, and the current limiting circuit 16 changes the current amount of one sensor of FIG. 6 to, for example, 50.
It is limited to μA.

In this way, by providing the current limiting circuit 16,
By reducing the current flowing into one sensor, even _if the number n of the sensors S _{1 to} Sn connected to the receiver 1 increases, the line current (line current) It is possible to prevent an increase in the number of 1) and to prevent the relay of the receiver 1 from malfunctioning.

However, if the current flowing through the sensor is too small due to the current limitation, the first problem is that when the power consumption of the sensor is large (for example, during self-test).
In addition, the power supply voltage in the sensor drops, causing a reset problem.

This is shown in FIG. In addition,
FIG. 8 shows the sensor a when the sensor consumes power.
The voltage changes at points a and b are shown. At the voltage at points a and b, the broken line shows the case where the current of the sensor is small (50 μA) due to current limitation, and the solid line shows the current of the sensor due to current limitation. The case is large (250 μA). Figure 8
As can be seen from the above, when the current of the sensor is small due to the current limit, when the power consumption of the sensor is large, the voltage at the point a of the sensor decreases to, for example, 3 V or less. The voltage also drops to, for example, 3 V or less, and the voltage at the point b of the sensor drops to or below the reset voltage, which causes a problem of resetting.

If the current flowing through the sensor is reduced by the current limitation, the second problem is that the rise time at power-on becomes long. If the current flowing through the sensor is made too small, the voltage drop due to the start-up process after reset release may be large, and may be below the reset voltage.

This is shown in FIG. In addition,
FIG. 9 shows the voltage changes at the points a and b of the sensor when the power of the receiver 1 is turned on (when the power is turned on), and the broken line indicates the voltage at points a and b. The case where the current of the sensor is small (50 μA) due to the current limitation is shown, and the solid line shows the case where the current of the sensor is large (250 μA) due to the current limitation.

As can be seen from FIG. 9, when the current of the sensor is small due to the current limitation, the rise time at power-on becomes long. Further, when the current of the sensor is small due to the current limitation, the voltage at the point a of the sensor decreases to, for example, 3 V or less when the power consumption of the sensor is large, and at this time, the voltage at the point b of the sensor also decreases. If the voltage drops to 3 V or less and the voltage at the point b of the sensor drops to the reset voltage or less, a problem of resetting occurs.

As described above, in the conventional sensor, if an attempt is made to reduce the current of the sensor by limiting the current in order to prevent the malfunction of the receiver, the sensor may malfunction.

An object of the present invention is to provide a sensor capable of preventing malfunction of a receiver and also malfunction of the sensor.

[0023]

In order to achieve the above object, the invention according to claim 1 is a sensor which is connected to a receiver through a line, and which receives a signal due to a large current flowing through the line. Current limiting means for limiting the current of the sensor flowing in the line to prevent malfunction of the machine, and switching means for switching the current limiting amount in the current limiting means according to the amount of electric power required for the processing of the sensor. It is characterized by having.

According to a second aspect of the present invention, there is provided a sensor connected to a receiver through a line, and the sensor is connected to the line to prevent malfunction of the receiver due to a large current flowing through the line. Current limiting means for limiting the current of the vessel,
The present invention is characterized in that it has switching means for switching whether or not to limit the current by the current limiting means according to the amount of electric power required for the processing of the sensor.

The invention according to claim 3 is the sensor according to claim 1 or 2, wherein the sensor gives a predetermined alarm signal to the receiver and the receiver outputs the alarm. When a predetermined delay time is provided in the receiver until the time, the time for flowing a large current in the current limiting means, or the time for which the current limiting means does not perform the current limitation is the predetermined time of the receiver. It is characterized by being set shorter than the delay time.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIG. 10 is a diagram showing a configuration example of a sensor according to the first embodiment of the present invention. Referring to FIG. 10, the sensor is a sensor (for example, a fire sensor) that is connected to the receiver through a line, in order to prevent malfunction of the receiver due to a large current flowing through the line. Current limiting means 101 for limiting the current of the sensor flowing in the line, and current limiting means 10
1 has switching means 102 for switching the current limiting amount according to the amount of electric power required for processing of the sensor.

FIG. 11 is a diagram showing a concrete example of the configuration of the detector (eg, fire detector) shown in FIG. In FIG. 11, the same parts as those in FIG. 6 are designated by the same reference numerals.
Referring to FIG. 11, the sensor includes a light emitting circuit 11,
A light receiving circuit 12, a processing circuit (for example, a CPU) 23,
The non-volatile memory 14, the first constant voltage circuit 15, and the second
Constant voltage circuit 17, current limiting circuit 26, and alarm circuit 1
8, a transmission circuit 19 and capacitors C1, C2 and C3.

Further, FIG. 12 shows an example of the current limiting circuit 26 and the processing circuit 23 used in the sensor of FIG.

In the configuration example of FIGS. 11 and 12, FIG.
10 is realized by the current limiting circuit 26, and the switching means 102 in FIG. 10 is the processing circuit 23.
It is realized by.

In the examples of FIGS. 11 and 12, the current limiting means 1
The current limiting circuit 26 as 01 is configured to limit the current of the sensor to two types, for example, 50 μA and 250 μA, and the current of the sensor is set to 50 μA by the switching signal from the processing circuit 23 as the switching means 102. It can be made smaller or switched to a larger one of 250 μA.

First as shown in FIGS. 10, 11 and 12
In the sensor of this embodiment, the current limiting means 101 (current limiting circuit 26) is normally switched by the switching means 102 (processing circuit 23) so that the current of the sensor is small. On the other hand, when a large amount of current is required at power-on, self-test, communication, etc., the current limiting means 101 (current limiting circuit 26) is switched to the switching means 102 so that the current of the sensor becomes large. It is switched by the (processing circuit 23).

More specifically, a processing circuit (eg CPU)
If it is known that the current consumption of 23 will be large (for example, by capturing a write signal to an element with a large current consumption (for example, the nonvolatile memory 14 that requires a large power at the time of writing)), the processing circuit (CPU) 23 Can control the current limiting amount of the current limiting unit 101 (current limiting circuit 26).

As described above, in the first embodiment of the present invention, the sensor connected to the receiver 1 through the line prevents malfunction of the receiver 1 due to a large current flowing through the line. In order to limit the current of the sensor flowing in the line, the current limiting means 101 and the switching means 102 for switching the current limiting amount in the current limiting means 101 according to the amount of electric power required for the processing of the sensor are provided. Therefore, it is possible to prevent malfunction of the receiver and malfunction of the sensor. That is, it is possible to reliably prevent the problems shown in FIGS. 8 and 9 from occurring.

As in the example shown in FIG. 1, a predetermined delay time is received until the sensor gives a predetermined alarm signal to the receiver 1 and the receiver 1 outputs the alarm. When provided in the device 1, the time for flowing a large current in the current limiting means 101 is set to be shorter than the predetermined delay time of the receiver 1. That is, when the time during which a large current flows is longer than the predetermined delay time of the receiver 1, the receiver 1
Malfunctions (in the example of FIG. 1, the reporting relay R
However, if the time during which a large current flows is shorter than the predetermined delay time of the receiver 1, the malfunction of the receiver 1 can be prevented.

Second Embodiment FIG. 13 is a diagram showing a configuration example of a sensor according to a second embodiment of the present invention. Referring to FIG. 13, this sensor is a sensor (for example, a fire sensor) that is connected to the receiver through a line, in order to prevent malfunction of the receiver due to a large current flowing through the line. Current limiting means 101 for limiting the current of the sensor flowing in the line, and current limiting means 10
It has switching means 202 for switching whether or not to limit the current by 1 according to the amount of electric power required for the processing of the sensor. In FIG. 13, when the switch SW is OFF, the current limiting means 101 limits the current,
When the switch SW is ON, the current limiting means 101 does not limit the current. In this second embodiment,
The switching means 202 specifically turns the switch SW on and off.
By performing FF, whether or not to limit the current by the current limiting means 101 is switched.

FIG. 14 is a diagram showing a specific configuration example of the sensor of FIG. Note that FIG. 14 corresponds to FIG. 12 of the first embodiment. In the configuration example of FIG.
13 is realized by the current limiting circuit 26, and the switching means 202 in FIG. 13 is the processing circuit 33.
It is realized by.

Specifically, in the example of FIG. 14, the current limiting circuit 26 is configured to limit the sensor current to, for example, 50 μA. In this case, the switch SW is turned on by the switching signal from the processing circuit 33 as the switching means 202.
In the case of FF, the current of the sensor can be made as small as 50 μA by the current limiting circuit 26, while when the switch SW is ON, the current limiting circuit 26 does not perform the current limiting and the current of the sensor is, for example, 250 μA.
It can be a big one.

In the sensor of the second embodiment as shown in FIG. 13 and FIG. 14, the switch SW is turned off so that the current of the sensor becomes small at normal time. The current is limited by the limiting circuit 26). On the other hand, when a large amount of current is required at the time of power-on, self-test, communication, etc., the switch SW is turned on so that the current of the sensor becomes large. No current limiting is provided by circuit 26).

More specifically, a processing circuit (eg CPU)
If it is known that the current consumption amount of 33 is large (for example, by capturing a write signal to an element having a large current consumption (for example, the nonvolatile memory 14 that requires a large power at the time of writing)), the processing circuit (CPU) 33 Can control ON / OFF of the switch SW.

As described above, according to the second embodiment of the present invention, the sensor connected to the receiver 1 through the line prevents malfunction of the receiver 1 due to a large current flowing through the line. Therefore, there are provided a current limiting means 101 for limiting the current of the sensor flowing in the line, and a switching means 202 for switching whether or not the current limiting means 101 performs the current limitation according to the amount of electric power required for the processing of the sensor. Since it has, it is possible to prevent malfunction of the receiver and malfunction of the sensor. That is, it is possible to reliably prevent the problems shown in FIGS. 8 and 9 from occurring.

As in the example shown in FIG. 1, a predetermined delay time is received until the sensor gives a predetermined alarm signal to the receiver 1 and the receiver 1 outputs the alarm. When provided in the device 1, the time for supplying a large current is set to be shorter than the predetermined delay time of the receiver 1. That is, when the time during which a large current flows is longer than the predetermined delay time of the receiver 1, the receiver malfunctions (erroneously reports), but the time during which a large current flows is determined by the predetermined time of the receiver 1. If the delay time is shorter than the delay time, the malfunction of the receiver 1 can be prevented.

In the specific example of the first or second embodiment described above, as shown in FIG. 11, FIG. 12, or FIG. 14, the current limit is switched. For example, it is possible to switch the current limitation by the configuration examples shown in FIGS. 15 and 16.

That is, in the configuration example of FIG. 15, the first current limiting circuit 4 for limiting the current to a magnitude of 50 μA, for example.
6 and the second, which limits the current to, for example, 250 μA
When the switch SW is turned off by the switching signal from the processing circuit 43, the current of the sensor is reduced to 50 μA by only the current limiting of the first current limiting circuit 46. On the other hand, when the switch SW is ON, the current limiting amount (300 μA) obtained by adding the current limiting amount (50 μA) of the first current limiting circuit 46 and the current limiting amount (250 μA) of the second current limiting circuit 47. The sensor current to 300 μA
Can be a big one.

Further, in the configuration example of FIG. 16, the first current limiting circuit 46 for limiting the current to a magnitude of 50 μA, for example.
And a second current limiting circuit 47 that limits the current to a magnitude of, for example, 250 μA, and the switch SW causes the first current limiting circuit 46 to operate in response to a switching signal from the processing circuit 43.
When set to the side, the first current limiting circuit 4
The current limit of 6 allows the current of the sensor to be as small as 50 μA, while the switch SW is set to the side of the second current limit circuit 47, the second
The current limiting amount of the current limiting circuit 47 (250 μA) enables the current of the sensor to be as high as 250 μA.

Since the configuration examples of FIGS. 15 and 16 are configured so that the current limiting amount in the current limiting means is switched by the switch SW by the switching signal, the first example
Can be regarded as a concrete example of the embodiment.

In each of the above examples, the switching of the current limiting amount is performed in two steps, but the switching of the current limiting amount is
The number of steps is not limited to two, and switching may be performed in multiple steps depending on the operating status of the sensor. Also, switching the current limit is
In addition to switching by software of the microcomputer, switching by hardware may be performed.

[0048]

As described above, according to the first aspect of the invention, the sensor is connected to the receiver through the line, and the receiver malfunctions due to the large current flowing through the line. In order to prevent this, the current limiting means for limiting the current of the sensor flowing in the line, and the switching means for switching the current limiting amount in the current limiting means according to the amount of electric power required for the processing of the sensor. Therefore, it is possible to prevent malfunction of the receiver and malfunction of the sensor. That is, when a large amount of electric power is required at the time of power-on or self-test, the amount of current can be increased to supply the electric power required by the sensor. Also, during normal monitoring, the peak current during normal monitoring can be suppressed by reducing the amount of current,
It is possible to prevent the receiver from malfunctioning.

According to the second aspect of the invention, the sensor is connected to the receiver through a line, and the sensor is connected to the line to prevent malfunction due to a large current flowing through the line. The current limiting means for limiting the current of the flowing sensor, and whether or not to limit the current by the current limiting means,
Since it has the switching means for switching according to the amount of electric power required for the processing of the sensor, it is possible to prevent the malfunction of the receiver and the malfunction of the sensor. That is, when a large amount of electric power is required when the power is turned on or when a self test is performed, the electric current required by the sensor can be supplied by not performing the current limitation by the current limiting means. Further, during the normal monitoring, the peak current during the normal monitoring can be suppressed by limiting the current by the current limiting means, and the malfunction of the receiver can be prevented.

Further, according to the invention of claim 3, in the sensor of claim 1 or 2, the sensor gives a predetermined alarm signal to the receiver and the receiver issues the alarm. When a predetermined delay time is provided in the receiver until the output of the current limiter, the time for which a large current flows in the current limiter, or the time when the current limiter does not limit the current, Since it is set shorter than the predetermined delay time, malfunction of the receiver can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration example of a P-type system.

FIG. 2 is a diagram showing a configuration example of _one sensor (for example, S ₁ ) used in the system of FIG.

FIG. 3 shows a state when a tester is further connected between terminals T and T ₀ in the system as shown in FIG. 1 and communication (testing) is performed between the tester and the sensor. It is a figure.

FIG. 4 is a diagram showing a configuration example in which a tester 20 is further connected between terminals T and T ₀ in the system as shown in FIG.

FIG. 5 is a diagram showing in detail the operation of the receiver 1 shown in FIGS. 3 (d) and 3 (e).

FIG. 6 is a diagram showing a configuration example of a sensor.

7 is a diagram showing an example of a current limiting circuit used in the sensor of FIG.

FIG. 8 is a diagram for explaining a first problem that occurs when the current flowing through the sensor is too small due to current limitation.

FIG. 9 is a diagram for explaining a second problem that occurs when the current flowing through the sensor is reduced by limiting the current.

FIG. 10 is a diagram showing a configuration example of a sensor according to the first embodiment of the present invention.

11 is a diagram showing a specific configuration example of the sensor (for example, a fire sensor) of FIG.

12 is a diagram showing an example of a current limiting circuit and a processing circuit used in the sensor of FIG.

FIG. 13 is a diagram showing a configuration example of a sensor according to a second embodiment of the present invention.

FIG. 14 is a diagram showing a specific configuration example of the sensor of FIG.

15 is a diagram showing a specific configuration example of the sensor of FIG.

16 is a diagram showing a specific configuration example of the sensor of FIG.

[Explanation of symbols]

1 receiver 11 Light emitting circuit 12 Light receiving circuit 23 Processing circuit 14 Non-volatile memory 15 First constant voltage circuit 17 Second constant voltage circuit 18 Notification circuit 19 Transmission circuit 20 tester 26 Current limiting circuit 101 Current limiting means 102 switching means 202 switching means 33 Processing circuit 43 Processing circuit 46 First Current Limiting Circuit 47 Second current limiting circuit

Continued front page    (72) Inventor Ryuichi Yamazaki             1-11-6 Hatagaya, Shibuya-ku, Tokyo Ni             Tan Co., Ltd. (72) Inventor Yuki Yoshikawa             1-11-6 Hatagaya, Shibuya-ku, Tokyo Ni             Tan Co., Ltd. F-term (reference) 5G405 AA01 CA09 DA21 EA43 EA60

Claims (3)

[Claims] 1. A sensor connected to a receiver through a line, the current limiting limiting a current of the sensor flowing through the line to prevent malfunction of the receiver due to a large current flowing through the line. And a switching means for switching the current limiting amount in the current limiting means according to the amount of electric power required for processing of the sensor. 2. A sensor connected to a receiver through a line, the current limiting limiting a current of the sensor flowing through the line to prevent malfunction of the receiver due to a large current flowing through the line. And a switching means for switching whether or not to limit the current by the current limiting means according to the amount of electric power required for the processing of the sensor. 3. The sensor according to claim 1, wherein the sensor gives a predetermined alarm signal to the receiver and the receiver outputs a predetermined delay. When the time is provided in the receiver, the time during which a large current flows in the current limiting means or the time during which the current limiting means does not limit the current is set to be shorter than a predetermined delay time of the receiver. A detector characterized by the following.