JPH0555920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dual-sensitivity type sensor having two and three types of sensitivity defined by the technical standards for automatic fire alarm equipment under the Fire Service Act.

[Background Art] FIG. 1 shows a conventional dual-sensitivity sensor. In this conventional example, a configuration is used in which a type 2 sensitivity signal line _L1 and a type 3 sensitivity signal line _L3 are connected to the control circuit section 1 via diodes D _a and D _b in the same _direction . _Db was used to prevent backflow.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and its _{object is} to
To provide a dual-sensitivity type sensor which does not require the use of a signal line and can always supply power to a signal detection circuit from a signal line with sufficient current supply.

[Disclosure of the Invention] (Embodiment 1) (Structure) The circuit of this embodiment 1 is shown in FIG. In the figure, reference numeral 1 denotes a control circuit section including a signal detection circuit 2 to be described later, and from this control circuit section 1, detection outputs of 2-type sensitivity and 3-type sensitivity are connected to 2-type switching circuits 3 and 3-type switching circuits, respectively. Circuit 4 thyristor
It is designed to be generated as a trigger signal for SCR ₁ and SCR ₂ . Cyrist SCR ₁ is a type 2 sensitivity signal line.
The thyristor SCR 2 is connected in parallel between L ₁ and the common signal line L _c , and the thyristor SCR ₂ is connected between the 3-sensitivity signal line L ₂ and the common signal line L _c
are connected in parallel. A resistor is connected between the power input terminal of the control circuit section 1 and the second type sensitivity signal line _L1 .
R ₇ and a PNP type transistor with a common base
A series circuit with Tr ₁ ' is inserted, and a resistor is connected between the power input terminal of the control circuit section 1 and the 3rd sensitivity signal line L ₂ .
A series circuit of R ₈ and a PNP type transistor Tr ₂ ′ with a common base is inserted, and the respective transistors Tr ₁ ′,
Connect the base of Tr ₂ ′ to a common signal line through resistors R ₅ and R ₆
Connected to _Lc . Note that a manual switch S is inserted in the base circuit of the transistor Tr ₁ '.

The sensor A is composed of a control circuit section 1 and switching circuits 3 and 4 of both transistors Tr ₁ ' and Tr ₂ '. B is a receiver, and this receiver B is equipped with a DC power supply that applies DC voltage between the second sensitivity signal line _L1 and the common signal line _Lc via the reception relay _Ry1 .
E ₁ and 3-sensitivity signal line L ₂ via receiving relay Ry ₂
and a DC power supply E ₂ that applies a DC voltage between the relays and the common signal line L _c , and the power supply voltages applied to the relays Ry ₁ and Ry ₂ are both the same voltage.

The control circuit section 1 has a constant voltage circuit 9 at the power input terminal connecting the signal lines L ₁ and L ₂ as shown in FIG.
is connected and the thyristor SCR ₁ of the second type switching circuit 3 is not turned on, the reference voltage of the constant voltage circuit 9 is determined by the Zener diode ZD ₁ , and the circuit voltage corresponding to the second type sensitivity is determined by the signal detection circuit. When the thyristor SCR ₁ is turned on, the Zener diode ZD ₂ is connected to the circuit through the diode D ₃ so that the voltage is applied to the constant voltage circuit 9.
The reference voltage of 3 is determined by the Zener diode ZD ₂ .
A circuit voltage corresponding to the species sensitivity is applied to the signal detection circuit 2.

The signal detection circuit 2 is composed of, for example, a photoelectric sensor, and the detection signal is sent to the next stage comparison processing circuit 4. After the comparison processing circuit 4 compares and judges the detection signals, it is sent to the signal processing circuit 8. The waveform is shaped by

The output of the signal processing circuit 8 is the thyristor _SCR1 ,
This is the control signal for the circuit that creates the trigger signal for SCR _2. The circuit that creates the trigger signal is composed of voltage detection elements PUT ₁ , PUT _2, etc., and is connected to the power supply line in the control circuit section 1 for common communication. Between line L _c
PNP transistor Tr ₃ ′, resistor R ₃ , diode
D ₄ and a capacitor C ₁ are connected in series, and the base of the transistor Tr ₃ is connected to the signal processing circuit 8. The connection point between the capacitor C ₁ and the diode D ₄ is connected to the anode of the voltage detection element PUT ₁ , and the reference voltage from the signal processing circuit 8 is connected to the gate of the voltage detection element PUT ₁ . It is connected to the gate of thyristor SCR ₂ of circuit 4. The collector side of transistor Tr ₃ is also connected to the emitter of transistor Tr ₄ , and the collector side of transistor Tr ₄ is connected to the common signal line L _c through a series circuit of resistor ₄ , diode D ₅ , and capacitor C ₂ . , the connection point between the diode D ₅ and the capacitor C ₂ is connected to the anode of the voltage detection element PUT ₂ , and the reference voltage from the signal processing circuit 8 is connected to the gate of the voltage detection element PUT ₂ . Thyristor of switching circuit 3
Connected to the gate of SCR ₁ . transistor
The base of Tr ₄ is connected to the second type signal line L ₁ via a resistor R ₇ and a diode D ₃ . D ₃ to _{D 5} are all backflow prevention diodes.

(Operation) Normally, both transistors Tr ₁ and Tr ₂ are turned on, and a circuit voltage is applied to the input of the constant voltage circuit 9 through the respective transistors Tr ₁ and Tr ₂ . The constant voltage circuit 9 supplies the control circuit section 1 with an output voltage determined by the Zener diode _ZD1 .

Next, when the detected smoke concentration increases and exceeds the level corresponding to the second type of sensitivity, a comparison signal is outputted from the comparison processing circuit 4, which compares and processes the detection signals from the signal detection circuit 2, to the signal processing circuit 8. The signal processing circuit 8 receives this comparison signal and outputs a signal that sets the base of the transistor Tr ₃ to "L" in order to turn on the transistor Tr ₃ . Therefore, the base current flows through the transistor _Tr3 , turning it on. this transistor
Turning on Tr ₃ charges the capacitor C ₁ and increases the anode voltage of the voltage sensing element PUT ₁ . Here, a constant reference voltage is applied to the gate of voltage detection element PUT ₁ , and the time from the start of charging until the voltage of capacitor C ₁ exceeds the above reference voltage is 2.
The capacitance of capacitor _C1 is set to correspond to the impression time of the species. Now, when the anode voltage of voltage sensing element PUT ₁ exceeds the gate voltage, that is, 2
After the seed impression time has elapsed, the voltage sensing element PUT ₁
is turned on, and the thyristor SCR ₁ of the type 2 switching circuit 3 is turned on. When this is turned on, an exciting current flows through the receiving relay Ry ₁ of the receiver B, causing it to operate.

Further, when the thyristor SCR ₁ is turned on, the transistor Tr ₁ is bypassed between the emitter and the base, so that it is turned off, and the circuit voltage is applied to the input of the constant voltage circuit 9 only through the transistor Tr ₂ .

Furthermore, when the thyristor SCR ₁ is turned on, current flows through the diode D ₃ and the thyristor SCR ₁ , and the output voltage of the constant voltage circuit 9 is lowered by the Zener diode ZD ₂ , resulting in the sensitivity of the signal detection circuit 2. becomes lower and shifts from 2nd type sensitivity to 3rd type sensitivity. Due to this decrease in sensitivity, the signal detection circuit 2
Since the detection signal disappears, the comparison signal from the comparison processing circuit 4 is no longer input to the signal processing circuit 8. Therefore, the signal processing circuit 8 sets the output to "H" and turns off the transistor _Tr3 . If transistor Tr ₃ turns off, current will no longer flow, so the voltage detection element
PUT ₁ is also turned off, but the thyristor SCR ₁ is turned on and the current flows to maintain the on state. Now, when the detected smoke concentration further increases and exceeds the level corresponding to the three types of sensitivity, a comparison signal is outputted to the signal processing circuit 8 from the comparison processing circuit 4 which compares and processes the detection signals from the signal detection circuit 2. Upon receiving this comparison signal, the signal processing circuit 8 sets the output to "L" and converts the transistor
Turn on Tr ₃ . This turns on the transistor
Tr ₄ also turns on as the base current flows through the emitter, base, diode D ₃ and thyristor SCR ₁ . By turning on the transistor Tr ₄ , the capacitor C ₂ is charged and the anode voltage of the voltage detection element PUT ₂ is increased. Here, a constant reference voltage is applied to the gate of the voltage detection element PUT ₂ , and the time from the start of charging until the voltage of the capacitor C ₂ exceeds the above reference voltage corresponds to the three types of impression times. The capacitance of capacitor _C2 is set. Now, when the anode voltage of the voltage sensing element PUT ₂ exceeds the gate voltage, that is, when the three types of sensing time elapses, the voltage sensing element PUT ₂ is turned on, and the thyristor SCR ₂ of the three types of switching circuit 4 is turned on. This turning on causes an exciting current to flow through the receiving relay Ry ₂ of the receiver B, causing the receiving relay Ry ₂ to operate.

In this way, in response to turning on of the thyristors SCR ₁ and SCR ₂ , the receiving relay Ry ₁ of the receiver B is turned on.
Each Ry ₂ operates, and the receiver B performs reception control operations such as alarms according to each operation.

By the way, for example, when a large number of sensors A are connected to the second-class sensitivity signal line _L1 , there is a possibility that there is no margin for the amount of current supplied via the relay _Ry1 . Then, if switch S is opened, the transistor
Tr ₁ is turned off and power is supplied to sensor A only through the 3rd type sensitivity signal line L _3. Even if thyristor SCR ₁ of 2nd type switching circuit 3 is turned on,
It can function as a sensor without any problems. The resistors R ₅ and R ₆ are inserted so that when the thyristor SCR ₁ is turned on, breakdown of the transistor Tr ₂ due to the reverse voltage between the base and emitter of the transistor Tr ₁ occurs and the relay Ry ₂ does not operate.

(Embodiment 2) FIG. 4 shows a circuit diagram of Embodiment 2. In this embodiment, the base of transistor Tr ₂ is connected to the thyristor of type 2 switching circuit 3 via resistor R ₆ .
Connected to the anode of SCR ₁ .

(Operation) In standby state, transistor Tr ₂ is a thyristor.
Since SCR ₁ is off, no base current flows and therefore a circuit voltage is applied to control circuit section 1 only via transistor Tr ₁ . Then, in the same way as in the first embodiment, the control circuit section 1 turns on the thyristor SCR ₁ which operates with two types of sensitivity, and turns off the transistor Tr ₁ . At the same time, the base current of the transistor Tr ₂ flows, the transistor Tr ₂ is turned on, and a circuit voltage is applied to the control circuit section 1 via the transistor Tr ₂ . In the control circuit section 1, the reference voltage of the built-in constant voltage circuit 9 is set by the Zener diode ZD ₂ as in the second embodiment, and the sensitivity of the signal detection circuit 2 is switched from type 2 sensitivity to type 3 sensitivity. .

(Effects of the Invention) The present invention connects the type 2 sensitivity signal line to the control circuit section through a transistor whose base is grounded, and connects the type 3 sensitivity signal line to the control circuit section through another transistor whose base is grounded. Since the base circuit of one of the transistors is provided with a switch means for turning off the transistor, the transistor on the signal line side with a large number of connected sensors is turned off, and the transistor on the other signal line side, which has more margin, is always turned off. This has the effect of making it possible to receive power supply, and since the transistor can prevent reverse current, it has the effect of eliminating the need for a diode, which was conventionally required. The input terminal is connected to each signal line through the circuit to receive power supply, and when the circuit is in steady state, it outputs a voltage corresponding to 2 types of sensitivity, and when the 2 types of sensitivity switching circuit is operating, it outputs a voltage corresponding to 3 types of sensitivity. It is equipped with a voltage circuit, and the sensitivity is set by the output voltage of this constant voltage circuit, so the sensitivity can be changed without extracting the critical parts inside the sensor to the outside, which has the effect of increasing electrical noise tolerance. be.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional example, Fig. 2 is a circuit diagram of Embodiment 1 of the present invention, Fig. 3 is a circuit diagram embodying the main parts of the above, and Fig. 4 is a circuit diagram of Embodiment 2 of the present invention. 1 is a circuit diagram, 1 is a control circuit section, 3 is a type 2 switching circuit, 4 is a type 3 switching circuit, Tr ₁ , Tr ₂
is a transistor, S is a switch, L _c is a common signal line, L ₁ is a type 2 sensitivity signal line, L ₃ is a type 3 sensitivity signal line,
B is a receiver, E ₁ and E ₂ are DC power supplies, and SCR ₁ and SCR ₂ are thyristors.

Claims (1)

[Claims] 1. In a dual-sensitivity type sensor equipped with a control circuit unit that generates detection signals of two-sensitivity and three-sensitivity signals, two-sensitivity signal lines and three A type 2 switching circuit and a type 3 switching circuit driven by each of the detection signals described above are respectively connected between the type sensitivity signal line and the common signal line, and the type 2 sensitivity signal line is connected via a base-grounded transistor. At the same time, the three sensitivity signal lines are connected to the control circuit section via another base-grounded transistor, and a switch means is provided in the base circuit of one of the transistors to turn off the transistor. In the two-sensitivity type sensor equipped with the above-mentioned two-sensitivity type sensor, the control circuit unit receives power supply by connecting an input terminal to each signal line through each of the transistors described above, outputs a voltage corresponding to two types of sensitivity during normal operation, and outputs a voltage corresponding to two types of sensitivity. A two-sensitivity type sensor comprising a constant voltage circuit that outputs voltages corresponding to three types of sensitivity when the type sensitivity switching circuit is operated, and the sensitivity is set by the output voltage of the constant voltage circuit. 2. A dual-sensitivity type sensor according to claim 1, characterized in that a manual switch is inserted in series in the base circuit of one of the transistors to open the transistor and turn it off. 3. The base of the transistor inserted between the type 3 sensitivity signal line and the control circuit section is connected to the input side of the type 2 switching circuit connected to the type 2 sensitivity signal line. A two-sensitivity type sensor according to scope 1.