JP3687172B2 - Gas safety device alarm input / output device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an alarm input / output device for a gas safety device used in a gas supply path.
[0002]
[Prior art]
In recent years, for the purpose of safe use of city gas and LP gas, when the amount of fuel gas (hereinafter referred to as "gas") is measured and the amount of use increases abnormally, it is far from normal use. When it is detected that the gas passage has been used for a long time, a gas meter with a safety device for blocking the gas passage is becoming widespread.
[0003]
This type of gas meter with a safety device takes a gas flow rate detection signal into a control circuit, processes it with an internal microcomputer, monitors the gas flow rate, outputs a shut-off signal if there is an abnormality, and closes the shut-off valve. The gas meter with a safety device is equipped with a long-term reliable power source battery, such as a lithium battery, supplying the circuit current and the drive current of the shut-off valve. Have.
[0004]
Further, for the purpose of preventing a gas leak accident, as an additional function, there is a function of connecting and interlocking a gas leak alarm so as to close the shutoff valve in the same manner as described above when a gas leak is detected.
[0005]
There are two types of alarm input / output signal formats: one that simply captures the output signal of the alarm, and one that captures the output signal of the alarm while returning an answer signal from the gas meter to the alarm. Some of the two-way ones have an unconnected detection function that can detect the presence / absence of an alarm.
[0006]
FIG. 3 is a block diagram showing a conventional alarm input / output circuit. The alarm enable switch 1 outputs an alarm sampling signal to the alarm output forward path + in response to an input K-EN command. The alarm output return path is provided with an alarm detector circuit 4 which monitors the return of the alarm sampling signal and detects the alarm operation when the phototransistor 11 which is an internal component of the alarm is turned on.
[0007]
The unconnected enable switch 3 outputs an unconnected detection sampling signal to the alarm output return path according to the command of the input AM-EN. The alarm output forward path is provided with an unconnected detection circuit 2 that monitors the return of the unconnected detection sampling signal, detects the connection of the photodiode 12 which is an internal component of the alarm, and determines whether the alarm is connected. The input resistors R3 and R4 of the unconnected detection circuit 2 are set so as to pass only a small amount of current so that the conduction of the photodiode 12 can be confirmed.
[0008]
The unconnected enable switch 3 also serves as an answer enable switch. When an answer signal is returned to the alarm device, the unconnected enable switch 3 conducts in conjunction with the alarm device answering circuit 6 and causes the answer signal to flow through the photodiode 12. The load resistor R5 of the alarm answering circuit 6 is set so that a current sufficient to emit light from the photodiode 12 can be obtained.
[0009]
[Problems to be solved by the invention]
However, the conventional configuration has the following problems.
[0010]
(1) In the conventional alarm input / output device having the above-described bidirectional unconnected detection function, an alarm sampling signal is applied to the alarm output forward path +, and the unconnected detection circuit 2 provided in the forward path + Since an alarm sampling signal is applied in the same manner, an alarm sampling signal current flows through the unconnected detection circuit 2 and consumes an unnecessary internal current i.
[0011]
(2) In the case of adopting a bidirectional input / output signal format that does not require unconnected detection, conventionally, only the unconnected detection circuit 2 is omitted, but in this case, an unnecessary internal current i is used. Although there is no current required to drive the alarm enable switch 1 and alarm operation detection is frequently sampled, the current for this is not negligible for batteries-powered devices. .
[0012]
[Means for Solving the Problems]
An alarm input / output device of a gas safety device of the present invention comprises an alarm output forward path having an alarm enable switch and an unconnected detection circuit, and an alarm output return path having an unconnected enable switch and an alarm detector detection circuit. The connection detection circuit includes an internal current prevention circuit that opens and closes in synchronization with the operation timing of the unconnected enable switch.
[0013]
According to the present invention, current consumption can be reduced and battery life can be extended.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Means alarm output device Gas Safety device of the present invention includes a alarm enable switch and the non-connection detection circuit to an alarm output outward, comprises a alarm detecting circuit unconnected enable switch to the alarm output circuit return The unconnected detection circuit includes an internal current prevention circuit that opens and closes in synchronization with the operation timing of the unconnected enable switch.
[0015]
Also, the alarm comprises a alarm answer circuit a current limiting resistor to the output forward, the backward alarm output is configured to include a alarm detecting circuit and the alarm answer enable switch.
[0016]
The alarm output device Gas Safety device of the present invention, the internal current protection circuit provided in the alarm output forward path, working in operation timing unconnected enable switch which is different from the operation timing of the alarm enable switch, alarm enable In order to prevent the alarm sampling signal applied from the switch from being applied to the unconnected detection circuit, unnecessary internal current due to the alarm sampling signal is prevented.
[0017]
Also, always through the current limiting resistor alarm output forward, voltages are applied, the alarm leakage current nonoperating alarm output circuit less, can be omitted without any trouble alarm enable switch and thus alert The current driving the device enable switch can be reduced.
[0018]
Embodiments of an alarm input / output device of a gas safety device according to the present invention will be described below with reference to the drawings.
[0019]
FIG. 1 is a block diagram showing an embodiment of an input / output device of a gas safety device according to an embodiment of the present invention. An internal current prevention circuit 5 is inserted between an alarm output forward path + and an unconnected detection circuit 2. .
[0020]
The input of the internal current prevention circuit 5 is common to the input AM-EN of the unconnected enable switch 3, and the internal current prevention circuit 5 opens and closes in synchronization with the operation timing of the unconnected enable switch 3.
[0021]
The operation timing of the input K-EN of the alarm enable switch 1 and the input AM-EN of the unconnected enable switch 3 is different. When the alarm enable switch 1 is turned on, the internal current prevention circuit 5 is non-conductive, and the alarm sampling signal Is not applied to the unconnected detection circuit 2, and unnecessary internal current i is prevented from flowing.
[0022]
FIG. 2 is a block diagram showing an embodiment of an input / output device of a gas safety device according to another embodiment of the present invention, in which the unconnected detection circuit 2 is omitted from the configuration of FIG. 1 is replaced with a current limiting resistor 7.
[0023]
A voltage is always applied to the alarm output forward path through the current limiting resistor 7, but when the alarm is not activated, the phototransistor 11 in the alarm is off and the leakage current is small, and the alarm answering circuit 6 is also alarmed. It is turned off except for the answering operation. Current consumption is reduced by the absence of drive current of the alarm enable switch.
[0024]
The current limiting resistor 7 is for limiting the current flowing directly from the power source to the alarm answering circuit 6 during the alarm answering operation, and is set to a value sufficiently larger than the load resistance R5 of the alarm answering circuit 6. When the operation frequency of the alarm device answering circuit is low, the resistance value of the current limiting resistor 7 is larger than that of the load resistor R5, so that the internal current is not a problem.
[0025]
According to an embodiment of the obvious to the present invention from the description of the following following advantages are provided according to the alarm output device of a gas safety device.
[0026]
Since the internal current prevention circuit kept low consumption of power for a battery it is possible to design a small capacity of the battery, lower cost equipment providing child and can.
[0027]
In addition, since the alarm enable switch can be omitted, the cost of parts required for the alarm enable switch can be reduced, and equipment can be provided at a lower cost. In addition, since no current is required to drive the alarm enable switch, the battery life can be extended.
[0028]
【The invention's effect】
In the alarm input / output device of the gas safety device of the present invention, since the internal current prevention circuit keeps the consumption of the power supply battery low, the battery capacity can be designed to be small, and the equipment can be provided at a lower cost. .
[Brief description of the drawings]
Circuit diagram of the alarm output device of another embodiment of a gas safety device of FIG. 1 is a circuit diagram of the alarm device output device for a gas safety device of an embodiment of the present invention the present invention; FIG 3 】 Circuit diagram of alarm input / output device of conventional gas safety device 【Explanation of symbols】
1 Alarm Enable Switch 2 Unconnected Detection Circuit 3 Unconnected Enable Switch 4 Alarm Detection Circuit 5 Internal Current Prevention Circuit 6 Alarm Answer Circuit

Claims (1)

  The alarm output forward path includes an alarm enable switch and an unconnected detection circuit, the alarm output return path includes an unconnected enable switch and an alarm detection circuit, and the unconnected detection circuit is synchronized with the operation timing of the unconnected enable switch. An alarm input / output device of a gas safety device having an internal current prevention circuit that opens and closes.

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