JP3606351B2 - Abnormality detection method for microcomputer gas meter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an abnormality detection method in a battery-powered microcomputer gas meter for monitoring a gas usage state and improving maintenance, and more particularly to an abnormality detection method for a microcomputer gas meter capable of detecting abnormal energization.
[0002]
[Prior art]
Conventionally, in a battery-powered microcomputer gas meter, the battery voltage is regularly monitored in order to avoid troubles caused by a decrease in battery capacity. As a method of detecting a decrease in battery capacity, a current is passed through the maximum load of the battery in the microcomputer gas meter or a pseudo load equivalent to the maximum load, and the microcomputer monitors the battery voltage when the load is driven by the voltage detection circuit. It is common to display a drop in the number or issue a report. In the microcomputer gas meter system, the shut-off valve has a maximum load, but the pseudo load for voltage detection is reduced for the following reason.
[0003]
In this microcomputer gas meter, when it is determined that gas is abnormally used, the shutoff valve is driven to stop the gas supply, and its equivalent impedance is 10Ω. This equivalent impedance of 10Ω is the impedance of the coil that drives the shut-off valve. By energizing this coil for a certain period of time, the valve can be closed to stop the gas. Furthermore, this shut-off valve is a self-holding type that holds mechanically even when power is turned off in order to reduce battery consumption.
[0004]
FIG. 3 shows a conventional example of a microcomputer gas meter.
The figure is a system centered on a microcomputer 1 and is driven by a lithium battery 2. This system monitors the signals of the gas flow sensor 9, pressure sensor 10 and the seismic sensor 11, and if a gas usage abnormality, pressure abnormality or earthquake occurrence is detected, the microcomputer 1 drives the shut-off valve. A command is issued to the transistor 8 for use to close the shut-off valve 5, and the supply of gas is stopped.
The pseudo load 3 is for detecting a decrease in battery capacity, has the same impedance as the shut-off valve 5, and its terminal voltage is input to the voltage detection circuit 4. The voltage detection circuit 4 outputs a logic output to the microcomputer 1 when the terminal voltage during energization falls below a predetermined value. A signal is output from the microcomputer 1 by this output, and the display / notification means 12 displays / reports a decrease in battery capacity.
[0005]
A method for detecting a decrease in battery capacity will be described below.
First, when a command from the microcomputer 1 is sent to the battery capacity test transistor 7, the transistor 7 is turned on, the pseudo load energizing transistor 6 is immediately turned on, and a current flows through the pseudo load 3. If the transistor for energizing the pseudo load 3 is equivalent to the transistor 8 for driving the shutoff valve, the pseudo load 3 can be energized directly by one transistor.
[0006]
The terminal voltage of the pseudo load 3 is input to the voltage detection circuit 4. The voltage detection circuit 4 is typified by, for example, a voltage detection IC, and is a circuit or an element that outputs a logic output when an applied voltage becomes a predetermined voltage or less. In this case, the predetermined voltage of the voltage detection circuit 4 is set to the lowest operating voltage of the shutoff valve 5. An example of the minimum operating voltage of the shut-off valve 5 in the case of a lithium battery is 1.8V. When the terminal voltage of the pseudo load 3 in the energized state falls below the predetermined voltage, the voltage detection circuit 4 outputs a logic output to the microcomputer 1 and receives the output from the microcomputer 1 by the display / notification means 12 to reduce the battery capacity due to the LED. Is displayed, and a notification of low battery capacity is sent. Note that the microcomputer 1 does not accept the output signal of the voltage detection circuit 4 when the energization command to the pseudo load 3 is not issued from the microcomputer 1. In this way, the minimum operating voltage of the battery is set to 1.8 V, for example, and monitoring is performed only at this one point.
[0007]
[Problems to be solved by the invention]
As described above, in the case of detecting battery consumption by monitoring one point of the battery voltage, the minimum operating voltage of the shut-off valve must be monitored because of the fluctuation of the battery voltage due to the ambient temperature change and the guarantee of the low temperature operation. This is the actual situation. As a result, in a state other than a low temperature, even if the battery is consumed due to a circuit abnormality or the like, the battery voltage does not decrease so much, so that the abnormality detection of the battery is delayed.
For example, when the microcomputer control signal for the shut-off valve drive circuit is turned on due to latch-up or the like, the shut-off valve remains energized from the battery. At this time, the pseudo load equivalent to the shut-off valve is energized. If the battery is monitored and the like, the load of the battery becomes 10Ω ÷ 2 to 5Ω, and the battery voltage is drastically reduced. In such a case, the operation of the microcomputer itself may be abnormal, and display / reporting may not be possible.
Accordingly, an object of the present invention is to make it possible to detect an abnormality of a microcomputer gas meter early from an abnormality of a shutoff valve .
[0008]
[Means for Solving the Problems]
In order to such a solution, in this invention, can be found with a temperature sensor provided on a printed board to implement the battery microcomputer gas meter, by providing the temperature sensor in the shut-off valve itself, an abnormal early from the monitoring result of the temperature Like that.
[0009]
That is, according to the first aspect of the present invention, a battery, a microcomputer using the battery as a power source (also referred to as a microcomputer), and display / notification means controlled by the microcomputer are mounted on the printed board, For a microcomputer gas meter that drives a shut-off valve installed separately,
A temperature sensor is installed on each of the shut-off valve and the printed board, and the temperature difference between the two temperature sensors is monitored to detect an abnormality.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, and FIG.
As is clear from FIGS. 1 and 2, the first temperature sensor 13A and the second temperature sensor 13B are provided here. That is, the first temperature sensor 13A is mounted on the shutoff valve 5 itself (not shown), and the second temperature sensor 13B is mounted on the printed board 14 at a position away from the shutoff valve 5 as shown in FIG. .
[0011]
According to the above, when the shut-off valve drive circuit is in a short mode failure, a large current is discharged from the battery 2 to generate heat, and this is detected by the first temperature sensor 13A and judged by the microcomputer 1. Can be used to determine abnormality. Here, as the temperature sensor, an IC or the like capable of digitally outputting a value corresponding to the temperature is used.
[0012]
The second temperature sensor is provided for comparison, and is mounted away from the battery so that it is not affected even if the battery generates heat due to an abnormality. In other words, the abnormality can be detected only by the first temperature sensor 13A. For example, a temperature difference between two temperature sensors is obtained, and when this difference exceeds a predetermined value, it is determined that the abnormality is present, and display / notification is possible. Thus, the detection performance is improved. Therefore, one of the temperature sensors is installed in the coil part which is the heat generating part of the shut-off valve 5, and the other temperature sensor is installed in a predetermined position of the printed board 14, and the temperature difference between the two is monitored. 5 abnormality monitoring becomes possible.
[0013]
【The invention's effect】
According to the present invention, the abnormality of the microcomputer gas meter is detected particularly by monitoring the temperature difference between the battery and the shutoff valve. Therefore, the abnormality is detected relatively early compared to the conventional battery voltage-only monitoring method. The advantage is that it can be detected and displayed / reported before the battery is exhausted.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.
FIG. 2 is an explanatory diagram of a structural example corresponding to FIG. 1;
FIG. 3 is a configuration diagram showing a conventional example of a microcomputer gas meter.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Microcomputer (microcomputer), 2 ... Lithium battery, 3 ... Pseudo load, 4 ... Voltage detection circuit, 5 ... Shut-off valve, 6, 7, 8 ... Transistor, 9 ... Flow sensor, 10 ... Pressure sensor, 11 ... Feel Seismic device, 12 ... display / notification means, 13A, 13B ... temperature sensor, 14 ... printed board, 15 ... shut-off valve connection line, 16 ... notification line.

Claims (1)

A battery, a microcomputer powered by this battery ( also called a microcomputer ), and display / notification means controlled by this microcomputer are mounted on the printed board, and a shut-off valve installed separately from the printed board is driven. For microcomputer gas meter to
A first temperature sensor for detecting an abnormality of the shut-off valve is installed on the shut-off valve itself, and a second temperature sensor for comparison is installed on the printed board, and both of the first and second temperature sensors are installed. An abnormality detection method for a microcomputer gas meter, wherein an abnormality is detected by monitoring a detected temperature difference .

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