JPH10267969A - Voltage detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect also a voltage under a light load by using one voltage detector. SOLUTION: A light load 1 which is used to measure a circuit voltage in a low current and a heavy load 2 which is used to measure a circuit voltage in a high current are installed. The respective loads are electrified selectively by a light-load switch 3 and a heavy-load switch 4. On the other hand, an intermediate measuring point C is installed at the light load 1, and the electric position of the intermediate measuring point C at the light load 1 is decided in such a way that the voltage of the intermediate measuring point C becomes equal to the voltage of a measuring point D at the heavy load 2. Thereby, since a light-load voltage and a heavy-load voltage can be judged by an identical voltage, a plurality of voltages can be detected by one voltage detecting apparatus 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery voltage detector for a gas safety device used in a gas supply path.

[0002]

2. Description of the Related Art In recent years, for the purpose of safe use of city gas and LP gas, the amount of fuel gas (hereinafter referred to as gas) is measured. 2. Description of the Related Art A gas meter with a security device that shuts off a gas passage when used for a longer period of time than in a used state has become widespread.

A gas meter with a security device of this type takes a detection signal of a gas flow rate into a control circuit, processes the signal by a microcomputer, monitors the gas flow rate, outputs a cutoff signal if there is an abnormality, and closes the cutoff valve. .

A gas meter with a security device is provided with a long-term reliable power supply battery such as a lithium battery, supplies a circuit current and a drive current for a shut-off valve, and does not require battery replacement during the installation and use of the gas meter with a security device. It has the characteristic.

[0005] Nevertheless, if the battery is consumed for some reason and the voltage is low, there is a possibility that the operation of the shut-off valve cannot be ensured. If there is a tendency for the battery voltage to drop, a warning is displayed in advance indicating that the battery voltage has dropped. In addition, this type of conventional voltage detection device has a single set detection condition and only detects a specific voltage under a specific load.

[0006]

In the above-described conventional voltage detecting device, for example, voltage detection is performed only under heavy load conditions when the shut-off valve is operated, but not at light load conditions. In addition, in order to detect a voltage abnormality at light load, the voltage drop at light load is small, so it is necessary to set the detection voltage higher than that at heavy load. There is a problem that a plurality of voltage detection devices are required to perform the detection.

[0007]

In order to solve the above-mentioned problems, the present invention provides a light load for measuring a circuit voltage at a low current and a heavy load for measuring a circuit voltage at a high current. While a light load switch provided corresponding to the load and a heavy load switch are selectively energized, an intermediate measurement point is provided in the light load, and the voltage of the intermediate measurement point is set to the measurement point voltage of the heavy load. The electrical position of the intermediate measurement point of the light load is determined so as to be equal, and the light load voltage and the heavy load voltage are determined by the same voltage. According to the present invention, a plurality of voltages can be detected by one voltage detection device.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A voltage detecting device according to a first aspect of the present invention comprises a light load for measuring a circuit voltage at a low current for simulating the circuit voltage at a load, and a circuit at a high current. A heavy load for voltage measurement, a light load switch that opens and closes energization to a light load that selectively energizes each load, a heavy load switch that opens and closes energization to a heavy load, and measures the voltage of the selectively energized load. A voltage detection circuit that performs
An intermediate measurement point is provided at a position where a voltage equal to the measurement point voltage of the heavy load is generated. Since the intermediate measurement point voltage during the light load is equal to the heavy load measurement point voltage, the voltage can be detected by the same voltage detection circuit despite the circuit voltages at the time of light load and heavy load being different. In addition, a plurality of voltages can be determined by time-divisionally controlling the operation timing of the light load switch and the heavy load switch.

Further, the operation frequency of the light load switch and the heavy load switch is made different so that the operation frequency of the heavy load switch is set to be lower than the operation frequency of the light load switch. And the setting of the above operation reduces the frequency of heavy load voltage measurement with a large measurement current and increases the frequency of light load voltage measurement with a small measurement current instead. The current can be reduced.

[0010] Further, it is set so that the heavy load switch is operated after the light load voltage detects a predetermined voltage. And since the setting of the above operation starts the operation of the heavy load switch only from the time when the light load voltage catches the tendency of battery consumption and the heavy load voltage starts to be a problem,
When the battery capacity is sufficient, the measurement of the heavy load voltage, which is hardly necessary, is omitted, and the unnecessary current consumption of the heavy load measurement can be eliminated.

[0011] Further, there is provided a display device for displaying a voltage drop when the output results of the voltage detection circuit match a plurality of times. The display device indicates that the voltage has dropped when the output results of the voltage detection circuit match a plurality of times and the reproducibility of the voltage drop detection increases, so that the effect of the temporary battery voltage drop is eliminated. Then, it can be correctly displayed that the voltage has dropped.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a configuration diagram showing Embodiment 1 of a voltage detecting apparatus according to the present invention. In the drawing, the light load switch 3 is configured such that the internal constituent transistor 3-1 is set to “L” of the input signal EN1
Are conducted, and a current flows through the light load 1. The heavy load switch 4 switches the internal constituent transistor 4-
1, 4-2 conducts, and 4-2 conducts, so that 4-3 conducts. Therefore, current flows through the path of the transistor 4-1, the heavy load 2, and the transistor 4-3.

The light load 1 is composed of internal resistances R1 and R2, and an intermediate measurement point C is provided at a division point. The intermediate measurement point C is connected to the measurement input “IN” of the voltage detection circuit 5 in common with the voltage measurement point D of the heavy load. Assuming that the detection voltage of the voltage detection circuit 5 is VL, the voltage VH applied to both ends of the light load 1 is represented by VH = VL × (R1 + R2) / R2, and two types of VL and VH are common detection voltages. Enables voltage detection.

The input signals EN1 and EN2 are controlled in a time-division manner, and the light load switch 3 and the heavy load switch 4 do not conduct at the same time.
The microcomputer (not shown) reads the data of the output “OUT” of the voltage detection circuit 5 at the timing of (1), and enables the voltage detection under a light load and the voltage detection under a heavy load.

FIGS. 2A and 2B are an operational characteristic diagram and a circuit diagram of a voltage detection circuit in the voltage detection device of the present invention. In the figure, a voltage detection circuit 5 is connected to a reference voltage Vre.
f and the comparator 51 as main elements, and the voltage at the input terminal “+” of the comparator 51 is equal to the reference voltage Vre.
When the output falls below f, the output “OUT” is inverted to “L”,
Detects voltage drop.

FIG. 3 is a battery characteristic diagram showing the change of the battery voltage with the lapse of the use time of a lithium battery used in a gas safety device (not shown) which incorporates the voltage detection device of the present invention. It shows the correlation between hour voltage and heavy load voltage. As is evident from the figure, when the battery capacity is sufficient, the light load voltage and the heavy load voltage do not fluctuate over time. Also begins to change over time.

Therefore, based on the data of the correlation shown in the figure, the consumption of the battery can be almost determined by the characteristics of the light load voltage.
Then, only the heavy load current is detected every 25 hours, but the light load voltage is mainly detected.

As an example, the frequency of heavy load measurement is doubled and changed every 50 hours, and the current ratio of light load to heavy load is 1:
If it is set to 100, the light load measurement frequency can be additionally set every 15 minutes even with the same current consumption as when the heavy load current is detected. Practically, the current consumption can be reduced by a quarter even when measuring every hour.

Since the time variation of the heavy load voltage is small between 0 and T1 when the battery capacity is sufficient, the measured current of the heavy load voltage during this period is wasted and the light load voltage of the light load voltage with little battery consumption is consumed. It turns out that checking is enough.

When the battery starts to be consumed, the light load voltage changes,
If the heavy load voltage is detected from the time T1 at which the consumption tendency below the voltage V1 becomes clear, a change in the heavy load voltage can be accurately detected without consuming unnecessary current consumption until T1. .

FIG. 4 is a flowchart showing the operation of the display device for displaying the voltage drop of the voltage detecting device of the present invention. An example is shown in which a voltage drop is displayed when a voltage drop with respect to the reference value VH of the light load voltage is detected five times in succession and a voltage drop with respect to the reference value VL of the heavy load voltage is detected twice in succession. I have.

[0022]

As is apparent from the above description, the voltage detecting device according to the present invention has the following effects.

(1) Since a light load voltage and a heavy load voltage are determined by the same voltage and a plurality of voltages can be detected by one voltage detection device, the cost required for the voltage detection circuit can be reduced, and a plurality of voltage detections can be performed. When the circuit is used, the problem of the error of the detection voltage for each voltage detection circuit does not occur, and the relative error between the light load voltage and the heavy load voltage can be reduced.

(2) If the frequency of measurement of heavy load is reduced, the number of times of measurement of light load can be increased more than the number of times of measurement of heavy load which is reduced. The accuracy is improved.

(3) Since the battery consumption is determined by detecting the light load voltage with low current consumption and the detection of the heavy load voltage is started, useless measurement current for heavy load voltage detection can be reduced, and the battery capacity can be effectively reduced. Since it can be used, a relatively low capacity battery can be used, and the cost required for the battery can be reduced.

(4) Erroneous display due to a voltage drop is reduced, and work required for maintenance is reduced, so that labor costs can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a voltage detection device according to a first embodiment of the present invention.

FIG. 2A is a characteristic diagram of a voltage detection circuit in the device. FIG. 2B is a voltage detection circuit diagram of the device.

FIG. 3 is a battery characteristic diagram showing a change over time of a battery voltage in the device.

FIG. 4 is a flowchart showing a voltage drop of the apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light load 2 Heavy load 3 Light load switch 4 Heavy load switch 5 Voltage detection circuit

Claims (4)

[Claims] 1. A light load for measuring a circuit voltage at a low current, a heavy load for measuring a circuit voltage at a high current, a light load switch for opening and closing a current to the light load, and a switch to the heavy load. A heavy load switch for opening and closing energization, and a voltage detection circuit for measuring the voltage of the load, and an intermediate measurement point at a point where a voltage equal to the measurement point voltage of the heavy load is generated while energizing the light load. And a voltage detection device that determines a light load voltage and a heavy load voltage with the same voltage. 2. The voltage detecting device according to claim 1, wherein the operation frequency of the heavy load switch is lower than the operation frequency of the light load switch. 3. The voltage detecting device according to claim 1, wherein the heavy load switch is operated after the light load voltage has detected a predetermined voltage. 4. The voltage detection device according to claim 1, further comprising a display device, wherein when the output results of the voltage detection circuit match a plurality of times, the display indicates that the voltage has dropped.