Alarm device

Abstract

To provide an alarm device which allows control of an SCR and a notification unit only by a reset circuit without providing an exclusive control circuit.SOLUTION: An alarm device 1 comprises: a notification unit 2 which performs a notification operation; a signal holding circuit 3 which continues the notification operation of the notification unit 2; a reset circuit 4 which resets a holding operation of the signal holding circuit 3; and a reset signal generation circuit 5 which transmits a reset signal to the reset circuit 4. The reset circuit 4 is arranged upstream of the signal holding circuit 3. The reset circuit 4 is provided with a signal amplification element 7 which is in an on state in a standby state and performs an off operation by receiving the reset signal. Signal holding of an SCR 6 arranged downstream is canceled through the off operation of the signal amplification element 7 to stop the notification operation of the notification unit 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an alarm device that receives an abnormality detection signal transmitted from outside and notifies the occurrence of an abnormality. [Background technology]

[0002] Conventionally, there is an alarm device that receives an abnormality detection signal transmitted from the outside and continues the alarm operation by the alarm unit by using a signal amplification element and an SCR. For example, the alarm device described in Patent Document 1 is provided with an alarm control switching element (signal amplification element) that goes to one state in response to operation when an abnormality occurs, an alarm that sounds in response to one state of the alarm control switching element, and a self-holding switching element (SCR) that turns on in response to operation of an alarm stop switch, and the self-holding switching element that turns on forcibly changes the alarm control switching element to the other state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 63-44297 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the alarm device of Patent Document 1, in order to function the alarm stop switch when an additional abnormality is detected, it was necessary to provide a dedicated control circuit equipped with a pulse generating capacitor that resets the self-holding switching element, in addition to the alarm control switching element, which resulted in a complex structure and increased costs.

[0005] In view of the above problems, the present invention aims to provide an alarm device that enables control of the SCR and the notification section using only a reset circuit, without the need for a dedicated control circuit. [Means for solving the problem]

[0006] In order to achieve the above object, the invention described in claim 1 is an alarm device having an alarm unit that alerts the occurrence of an abnormality, a signal holding circuit that continues the alarm operation of the alarm unit, a reset circuit that resets the holding operation of the signal holding circuit, and a reset signal generating circuit that sends a reset signal to the reset circuit, wherein the signal holding circuit has an SCR that turns on when it receives an abnormality detection signal sent from the outside, and the SCR that has been turned on maintains its on state to continue the alarm operation of the alarm unit, the reset circuit is arranged upstream of the signal holding circuit and has a signal amplification element that turns off when it receives a reset signal, the signal amplification element is in an on state in a standby state where no reset signal is input, and supplies an operating current to the signal holding circuit, and the output of the signal holding circuit is turned off when the signal amplification element turns off, stopping the alarm operation of the alarm unit. The invention as set forth in claim 2 is characterized in that in the invention as set forth in claim 1, the signal amplifying element is a MOSFET, and the gate voltage changes in response to a reset signal. Effect of the Invention

[0007] The alarm device of the present invention includes a notification unit that notifies of the occurrence of an abnormality, a signal holding circuit that continues the notification operation of the notification unit, a reset circuit that resets the holding operation of the signal holding circuit, and a reset signal generating circuit that transmits a reset signal to the reset circuit, with the reset circuit being disposed upstream of the signal holding circuit. The reset circuit is provided with a signal amplifying element that is on in a standby state and turns off upon receiving a reset signal, and the signal holding of the SCR disposed downstream is released by the signal amplifying element turning off, thereby stopping the notification operation of the notification unit. Therefore, it is possible to continue / release the holding operation by the SCR of the signal holding circuit and the notification operation of the notification unit without the need to provide a dedicated control circuit for the reset circuit. [Brief description of the drawings]

[0008] [Figure 1]1 is a circuit diagram showing an alarm device according to the present invention; [Diagram 2] FIG. 1 is a circuit diagram showing an alarm device that controls a plurality of signal holding circuits and a plurality of reset circuits. [Diagram 3] FIG. 11 is a circuit diagram showing an alarm device in which the reset signal is a low-level signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a circuit diagram showing an alarm device 1 according to the present invention.

[0010] The alarm device 1 is a device that notifies the occurrence of an abnormality upon receiving an abnormality detection signal transmitted from an external device such as a ground leakage detector, etc. As shown in Fig. 1, the alarm device 1 is composed of an alarm unit 2 that performs an alarm operation, a signal holding circuit 3 that starts the alarm operation of the alarm unit 2 upon receiving the abnormality detection signal and continues the operation, a reset circuit 4 that resets the holding operation of the signal holding circuit 3, and a reset signal generation circuit 5 that transmits a reset signal to the reset circuit 4.

[0011] The alarm unit 2 is a mechanism for notifying by, for example, an LED or a buzzer, and the alarm operation is continued by a signal holding circuit 3. The signal holding circuit 3 has an SCR 6 that is turned on upon receiving an abnormality detection signal transmitted from an external device (not shown). SCR is an abbreviation for Silicon Controlled Rectifier, and represents a silicon controlled rectifier, that is, a thyristor, which is a semiconductor element capable of controlling current. Then, when the SCR 6 is turned on, it maintains the on state and controls the current to the alarm unit 2, thereby allowing the alarm unit 2 to continue its alarm operation. The alarm unit 2 may also be an external contact output circuit using a phototransistor.

[0012] The reset circuit 4 has a signal amplification element 7 that is turned off upon receiving a reset signal from the reset signal generation circuit 5, and is disposed upstream of the signal holding circuit 3. The signal amplification element 7 is, for example, a semiconductor element such as a transistor that can amplify or switch a signal. In the embodiment, the signal amplification element 7 is a MOSFET. A MOSFET is a transistor that combines a field effect transistor (FET) with a metal oxide semiconductor (MOS). In a standby state in which no reset signal is input, the signal amplification element 7 is in an on state, and is configured to supply an operating current to the signal holding circuit 3. The signal amplification element 7 that is turned off upon receiving the reset signal stops the current supplied to the signal holding circuit 3, and turns off the output of the signal holding circuit 3.

[0013] The reset signal generating circuit 5 is a circuit that transmits a reset signal to the reset circuit 4, and includes a reset switch 8 and a signal conversion element 9. The reset switch 8 can be switched on / off, and the switching method is appropriately selected. For example, it may be switched by a voltage or by operating a physical switch. The signal conversion element 9 is a transistor for switching a received high-level signal to a low-level signal. When the reset switch 8 is turned on in the reset signal generating circuit 5, a high-level signal is transmitted to the signal conversion element 9. Then, the signal conversion element 9 switches the signal to a low-level signal, which is transmitted from the signal conversion element 9 to the signal amplification element 7 of the reset circuit 4 as a reset signal. In this way, the signal amplification element 7 that receives the reset signal from the reset signal generating circuit 5 operates to be turned off.

[0014] The operation procedure of the alarm device 1 will now be described. During normal operation of the alarm device 1, the signal amplifier element 7 of the reset circuit 4 is in the ON state, and an operating current is supplied to the signal holding circuit 3. Then, for example, when an external device detects an abnormality such as a ground fault and sends an abnormality detection signal to the signal holding circuit 3, the SCR 6 of the signal holding circuit 3 receives the abnormality detection signal and turns ON. The SCR 6 that has turned ON continues the alarm operation of the alarm unit 2 while maintaining the ON state.

[0015] Subsequently, when the reset switch 8 is turned on for inspection or the like, a reset signal is sent from the reset signal generating circuit 5 to the reset circuit 4. Then, the signal amplifying element 7 of the reset circuit 4 receives the reset signal and turns off. When the signal amplifying element 7 turns off, the output of the reset circuit 4 is turned off and the power supply to the notification unit 2 and the signal holding circuit 3 is cut off, whereby the holding operation by the SCR 6 of the signal holding circuit 3 is released and the notification operation of the notification unit 2 is stopped.

[0016] The alarm device 1 of the embodiment described above includes the alarm unit 2 that notifies the occurrence of an abnormality, the signal holding circuit 3 that continues the alarm operation of the alarm unit 2, the reset circuit 4 that resets the holding operation of the signal holding circuit 3, and the reset signal generating circuit 5 that transmits a reset signal to the reset circuit 4, with the reset circuit 4 being disposed upstream of the signal holding circuit 3. The reset circuit 4 is provided with a signal amplifying element 7 that is on in a standby state and turns off upon receiving a reset signal, and the signal holding of the SCR 6 disposed downstream is released by the off-state of the signal amplifying element 7, thereby stopping the alarm operation of the alarm unit 2. Therefore, it is possible to continue / cancel the holding operation by the SCR 6 of the signal holding circuit 3 and the alarm operation of the alarm unit 2 without the need to provide a dedicated control circuit for the reset circuit 4.

[0017] The modified example will be described with reference to Figs. 2 and 3. Fig. 2 is a circuit diagram showing an alarm device 1a that controls a plurality of signal holding circuits 3 and a plurality of reset circuits 4. Fig. 3 is a circuit diagram showing an alarm device 1b in which the reset signal is a low-level signal. Incidentally, the components that exhibit the same effects as the components shown in FIG. 1 are given the same reference numerals as in FIG. 1, and the description thereof will be omitted.

[0018] As shown in FIG. 2, in the alarm device 1a, in the reset signal generating circuit 5, three signal conversion elements 9 are connected in parallel to the reset switch 8 in accordance with the number of reset circuits 4. Each of the signal conversion elements 9 is connected to the reset circuit 4, the notification unit 2 via the reset circuit 4, and the signal holding circuit 3 via the reset circuit 4. Here, since the signal amplifying element 7 is a MOSFET that can be operated with a small current, it is possible to reset a plurality of signal holding circuits 3 and a plurality of reset circuits 4 by a signal from one reset switch 8. In addition, although the circuit diagram shown in FIG. 2 shows a case where there are three reset circuits 4, the number of reset circuits 4 to be controlled can be easily changed by providing the signal conversion elements 9 in the reset signal generating circuit 5 in accordance with the reset circuits 4.

[0019] 3, an alarm device 1b does not require a signal conversion element 9 because the signal from the reset switch 8 is a low-level signal. Also, a signal amplification element 7b is a normal NPN-type transistor, not a MOSFET. According to the alarm device 1b configured in this manner, it is not necessary to use the signal conversion element 9, and therefore it is possible to reduce the number of parts.

[0020] The alarm device according to the present invention is not limited to the above-described embodiment, and the overall configuration of the alarm device as well as, for example, the configuration of the reset circuit can be appropriately modified as necessary. [Explanation of symbols]

[0021] 1, 1a, 1b... alarm device, 2... notification section, 3... signal holding circuit, 4... reset circuit, 5... reset signal generating circuit, 6... SCR, 7, 7b... signal amplifying element, 8... reset switch, 9... signal converting element.

Claims

1. An alarm device having a notification unit that notifies an occurrence of an abnormality, a signal holding circuit that causes the notification operation of the notification unit to continue, a reset circuit that resets the holding operation of the signal holding circuit, and a reset signal generation circuit that transmits a reset signal to the reset circuit, the signal holding circuit has an SCR that is turned on in response to an abnormality detection signal transmitted from an external device, and the SCR that has been turned on maintains the on state to continue the notification operation of the notification unit; the reset circuit is disposed upstream of the signal holding circuit and includes a signal amplifying element that receives the reset signal and turns off; The signal amplifying element is in an on-state in a standby state where the reset signal is not input, and supplies an operating current to the signal holding circuit, The signal holding circuit has its output turned off when the signal amplifying element is turned off, thereby stopping the annunciation operation of the annunciation section.

2. 2. The alarm device according to claim 1, wherein the signal amplifying element is a MOSFET, and the gate voltage of the MOSFET is changed by the reset signal.

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