JPH1194623A - Method for detecting failure of microcomputer-based gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the reliability by detecting the battery consumption and a failure of a microcomputer-based gas meter at its early stages. SOLUTION: The microcomputer-based gas meter, having a microcomputer 1, a shutoff valve 5, display and report means 12, and the like and using a battery 2 as its power supply is provided with a current detecting resistance 13 detecting a current from the battery 2 and with a transistor 15 bypassing the current detecting resistance 13. Any failure regarding the current and the consumption of the battery can be normally detected via the current detecting resistance 13, and when the shutoff valve 5 and the display and report means 12 or the like are driven, the transistor 15 is turned on by the microcomputer 1 and made to bypass the current detecting resistance 13 so as to prevent decrease in a driving current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery-operated microcomputer gas meter for monitoring gas usage and improving security, and more particularly to a method for detecting abnormal consumption of a battery.

[0002]

[Prior art]

1) Conventionally, in a battery-powered microcomputer gas meter,
The battery capacity is monitored regularly to avoid troubles caused by low battery voltage. As a method for detecting a decrease in battery capacity, a load current is applied to the maximum load in the microcomputer gas meter or a pseudo load equivalent to the load for at least the time required to drive the maximum load, and the voltage is The detection circuit detects that the terminal voltage of the load has dropped below a predetermined value, and sends a signal to a microcomputer (hereinafter, also referred to as a microcomputer) as a control device to indicate a decrease in battery capacity or to issue a notification. Ordinarily.

[0003] In a microcomputer gas meter, when it is determined that gas is abnormally used, a shut-off valve is driven to stop gas supply. This drive of the shut-off valve is the maximum load of a battery in the microcomputer gas meter. . Therefore, a decrease in the battery capacity is determined for a case where the load is the shutoff valve. To close the shutoff valve, the gas can be stopped by closing the valve by energizing the solenoid constituting the shutoff valve for at least 50 ms (ms: millisecond). In addition, this shut-off valve is of a self-holding type that keeps the valve closed mechanically even when power is turned off in order to reduce battery consumption of the microcomputer gas meter. Some valves can be used.)

FIG. 2 shows a conventional example of such a microcomputer gas meter, and FIG. 3 shows a relationship between a command to supply current to a dummy load and a terminal voltage of a battery. The circuit configuration of FIG. 2 is a system centered on the microcomputer 1 and is driven by the lithium battery 2.
This system comprises a gas flow sensor 9, a pressure sensor 10
The microcomputer 1 monitors the signal of the seismic sensor 11 and detects an abnormality in gas usage, an abnormality in pressure or an occurrence of an earthquake, and issues a command to the transistor 8 for driving the shut-off valve.
The shutoff valve 5 is closed, and the supply of gas is stopped. Simulated load 3
Is for detecting a decrease in battery capacity, has the same impedance as the shutoff valve 5, and its terminal voltage is input to the voltage detection circuit 4. The voltage detection circuit 4 outputs a logical output to the microcomputer 1 when the terminal voltage at the time of energization falls below a predetermined value. A signal is output from the microcomputer 1 by this output, and the display / notification means 12 displays / notifies a decrease in battery capacity.

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 (see time 0 in FIG. 3),
The transistor 7 is turned on (ON), the pseudo load energizing transistor 6 is immediately turned on, and a current flows through the pseudo load 3. As a transistor for energizing the dummy load 3, if it is equivalent to the shut-off valve driving transistor 8, a single transistor can be directly used as the dummy load 3.
Can be energized.

[0006] The terminal voltage of the dummy load 3 is
Has been entered. The voltage detection circuit 4 is a circuit or an element that outputs a logical output when an applied voltage becomes equal to or lower than a predetermined voltage, as represented by, for example, a voltage detection IC. In this case, the predetermined voltage of the voltage detection circuit 4 is set to the minimum operating voltage of the shutoff valve 5. One 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 dummy load 3 in the energized state becomes equal to or lower than the predetermined voltage, the voltage detection circuit 4 outputs a logical output to the microcomputer 1, and the microcomputer 1 receives the output and displays a logical
A signal is output to the notifying unit 12, and the display / notifying unit 12 displays an indication of a decrease in the battery capacity by an LED or a wireless notification of the decrease in the battery capacity. Note that the microcomputer 1 does not receive the output signal of the voltage detection circuit 4 when the microcomputer 1 has not issued an energization command to the dummy load 3.

Next, the relationship between the energization command when the dummy load 3 is actually energized and the terminal voltage of the battery will be described with reference to FIG. When an energization command is issued at time 0 and a current flows through the dummy load 3, the terminal voltage of the battery decreases. The energization command is sent for 100 ms longer than 50 ms, which is the time required for driving the shut-off valve 5. During this 100 ms, the microcomputer 1 monitors the output signal of the voltage detection circuit 4. Therefore, if the terminal voltage of the dummy load 3 does not drop below the predetermined value during this 100 ms, the logic output is not output from the voltage detection circuit 4 and the battery capacity is determined to have no problem. Since there is a difference between the terminal voltage of the dummy load 3 and the terminal voltage of the battery by the voltage drop of the dummy load energizing transistor 6, the terminal voltage of the dummy load 3 is also substantially the same as the terminal voltage of the battery in FIG. It can be treated as decreasing with the tendency.

Conventionally, the above-described detection of a decrease in battery capacity is performed, for example, every 24 hours. The reason for this is to minimize battery consumption due to the above-described operation, and cannot be shortened by orders of magnitude, for example, every hour. In addition, the battery design of the microcomputer gas meter calculates the current consumption assuming that the operation of the shut-off valve is 10,000 times in 10 years, for example, so that the total current consumption of all the operations is equal to or less than the battery capacity. I try to design.

[0009]

[Problems to be solved by the invention]

(1) As described above, when a decrease in battery capacity is detected by supplying electricity from a battery to a pseudo load equivalent to a shut-off valve for a time equal to or longer than the drive time of the shut-off valve, the detection time is about 24 hours.
It cannot be significantly shortened. However, the failure mode of the microcomputer gas meter is in a state different from that instructed by software of the microcomputer due to, for example, a latch-up of a port signal of the microcomputer or a failure of a transistor for turning off a power supply of a display / notification circuit. Sometimes. (2) The microcomputer gas meter itself is operating normally, but in some cases, the number of operations exceeds the number of operations assumed in the battery design due to a remarkable increase in the number of times of interruption, display and notification due to abnormal use of gas. Therefore, an object of the present invention is to enable early detection of battery consumption and abnormality,
Another object of the present invention is to make it possible to detect battery consumption by software and improve reliability.

[0010]

In order to solve such a problem, the invention according to claim 1 includes a microcomputer (referred to as a microcomputer), a shut-off valve controlled by the microcomputer, and display / notification means. A battery-driven microcomputer gas meter is provided with current detection means for detecting a current flowing out of the battery, and bypass means for bypassing the current detection means. When the apparatus including the display / notification means is driven, the current detection means is bypassed via the bypass means so as not to reduce the drive current of the apparatus in accordance with an instruction from the microcomputer. According to the first aspect of the present invention, the number of operations of each device is monitored by the microcomputer, and when the number of operations exceeds a predetermined value,
Display and notification can be made (the invention of claim 2).

[0011]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. As is clear from the drawing, the power supply from the battery to other circuits and the like except for the microcomputer 1 is performed through a current detection circuit using a resistor 13, which is different from FIG. Here, the drive currents of the shutoff valve 5 and the display / notification means 12 are, for example, 50
0 mA and 10 mA. Also, the flow sensor 9,
Outputs from the pressure sensor 10 and the seismic sensor 11 are basically contact output signals, and detection of a contact requires a detection current of about several tens of μA. Therefore, even if the output circuits of the flow sensor 9, the pressure sensor 10, and the seismic sensor 11 are kept on, the detected current is several tens of μA. is not.

However, since the drive currents of the shut-off valve 5 and the display / notification means 12 are extremely large as described above, the battery is significantly consumed by latch-up of the command port of the microcomputer 1 or failure of the short-circuit mode of the circuit. become.
When such an abnormal current flows, the current is detected by the current detection circuit, the shut-off valve 5 is closed according to the judgment of the microcomputer 1, and the display / notification means 12 notifies the maintenance person. When an abnormal current flows, there is a high possibility that the drive circuit of the shut-off valve 5 or the operation of the display / notification means 12 itself is abnormal. To the maintenance staff, and display / notification means 1
In the case where 2 is abnormal, the shut-off valve 5 is closed and the maintenance staff is notified that the gas cannot be used, so that the safety of gas use can be ensured.

Assuming that the current value for detecting an abnormality is, for example, 5 mA, which is half the drive current of the display / notification means 12, the voltage between the base and the emitter of the transistor 14 is 0.6V. , 0.6V / 5mA = 120Ω, and the current detection resistor 13 limits the operating current of the shut-off valve 5 and the display / notification means 12.
When the shut-off valve 5 and the display / notification means 12 operate, the transistor 15 allows the bypass.

By the way, as for the number of operations of the shut-off valve 5 and the display / notification means 12 and the like, for example, the operation of the shut-off valve, the battery capacity is determined assuming the number of operations of 10,000 times in 10 years as described above. ing. Therefore, for example, the microcomputer 1 counts the number of operations of the shut-off valve 5 and the display / notification means 12 and the like, while setting the number of operations assumed for 10 years, for example, and sets the shut-off valve when the count exceeds the set value. By closing 5 and displaying or notifying the fact by the display / notification means 12, the consumption of the battery of the microcomputer gas meter due to the abnormal use of gas can be detected at an early stage, and the safety of the system can be enhanced.

[0015]

According to the present invention, the consumption of the battery due to the abnormality of the microcomputer gas meter itself is detected by detecting the abnormal current from the battery, so that the operating current of the current detection circuit when the abnormal current does not flow is substantially reduced. Can be zero.
As a result, monitoring can be performed at all times, and the abnormality can be detected early. It is also possible to monitor the number of times of operation of the circuit and detect the consumption of the battery by software from the number of times. If these are used together, the reliability can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional example of a microcomputer gas meter.

FIG. 3 is an operation explanatory diagram of FIG. 2;

[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, 14, 15 ... transistor, 9 ... flow rate sensor, 10 ... pressure sensor, 11 ... seismic sensor, 12 ... display / notification means, 13 ... current detection resistor.

 ──────────────────────────────────────────────────続 き Continuation of the front page (71) Applicant 000005234 Fuji Electric Co., Ltd. 1-1-1, Tanabe Nitta, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture (72) Inventor Ikko Itsui 9-10 Misonodai, Fujisawa-shi, Kanagawa Prefecture (72) Inventor Katsutoshi Sakai 3-2-7-1-123 Takasago, Katsushika-ku, Tokyo (72) Inventor Shinichi Sato 543-15 Kitano-cho, Hachioji-shi, Tokyo 2-70 Aichi Clock & Electronics Co., Ltd. (72) Mitsuru Saito 1-2-70 Aichi Prefectural Nagoya City Atsuta-ku 1-2-70 Aichi Clock & Clock Co., Ltd. (72) Inventor Hideo Masuda Yanagimachi, Sachi-ku, Kawasaki City, Kanagawa Prefecture 70 Inside Yanagimachi Plant, Toshiba Corporation (72) Inventor Hirokuni Murakami 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Hirozumi Nakamura 1006 Kadoma Kadoma, Osaka Prefecture 1006 Address: Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A microcomputer (referred to as a microcomputer), a shut-off valve and a display / notification unit controlled by the microcomputer, and a current detection unit for detecting a current flowing out of the battery with respect to a battery-driven microcomputer gas meter. A bypass means for bypassing the current detection means, wherein the current detection means is always in an operating state, and when the apparatus including the shut-off valve and the display / notification means is driven, the current detection means is provided by a microcomputer. An abnormality detection method for a microcomputer gas meter, wherein the bypass current is bypassed through the bypass means so as not to reduce the drive current of the device in accordance with the instruction. 2. The microcomputer gas meter abnormality detection method according to claim 1, wherein the microcomputer monitors the number of times of operation of each device and, when the number of times of operation exceeds a predetermined value, displays and reports. .