JP2004132828A - Flow meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow meter capable of accurately and reliably integrating flow rates even after a battery is replaced, by forenoticing a battery voltage value which is the limit of guarantee for operation of a flow meter and stopping measuring of flow rate when the battery voltage value reaches a threshold value for measurement. <P>SOLUTION: The flow meter comprises a flow rate measuring means 2 that measures flow rate of a fluid, a central processor 3 that calculates flow rate based on the measurement result, and a first set voltage detecting means 5 that detects the fact that the voltage of battery has dropped to reach a first set voltage and makes a display device display a forenotice of measurement stop under control of the central processor 3. A second set voltage detecting means 6 detects the fact that the voltage of battery has reached a second set voltage value and stops a processing of measurement result for flow rate under control of the central processor 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flow meter that measures a flow rate of a fluid such as gas or water using a battery as a power supply.
[0002]
[Prior art]
Conventional flowmeters, for example, gas flowmeters used for homes, factories, and medical use are often installed outdoors, and a battery is used as a power source to operate the gas flowmeter from the viewpoint of convenience. Widely used.
Therefore, in such a gas flow meter, a central processing unit or the like is operated using a battery as a power source, and a gas flow rate measurement signal is processed, and the result of the calculation processing is used as information management as instantaneous data or integrated data of the gas flow rate. The data is transmitted to the department so that each data can be monitored on the display of the computer.
[0003]
Further, the information management department collectively manages gas flow data from a plurality of gas flow meters collectively, and therefore, it is important to control the voltage of the battery for each gas flow meter.
In a conventional gas flow meter that operates using a battery as a power source, when the voltage of the battery decreases, the decrease is reported to the surroundings by a display such as a lamp (for example, see Patent Literature 1), or a character displayed on a liquid crystal display is used. The contents are specifically shown on the display to call attention, a buzzer or the like is sounded to warn, and the information management department is notified by character display or sound.
Therefore, the administrator can recognize that the battery for driving the gas flow meter has been exhausted by receiving the notification, the alarm, or the notification, and take measures to replace the battery.
[0004]
[Patent Document]
JP-A-2-190715 (page 11, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, in such a conventional gas flow meter, since the battery is replaced only when the administrator notices the notification, the alarm or the notification, the gas flow rate is not changed until the battery is replaced. Measurement is continued, and the measurement and integration of the erroneous gas flow measurement value by the gas flow meter whose operation is not normal is performed. That is, the gas flow meter continues the measurement operation outside the guaranteed range.
[0006]
Therefore, when the battery replacement is performed and the measurement of the normal gas flow rate is restarted, the measurement value after the measurement restart is added to the integrated value of the gas flow rate measured when the measurement operation is abnormal, There is a problem that the reliability of the result of integrating the gas flow rate is greatly impaired.
[0007]
The present invention has been made in view of the conventional problems as described above, and a notice of a battery voltage value at which a flow measurement operation guarantee is limited, and the voltage value reaches a limit value at which a flow measurement operation cannot be performed. An object of the present invention is to obtain a flowmeter capable of continuously executing accurate and highly reliable flow integration including an integrated value before battery replacement even after battery replacement by stopping the flow measurement at that time.
[0008]
[Means for Solving the Problems]
The flow meter according to claim 1 of the present invention, a flow rate measuring unit that measures a flow rate of a fluid, a central processing unit that operates using a battery as a power source, and calculates a flow rate based on a measurement result by the flow rate measuring unit, First set voltage detecting means for detecting that the voltage of the battery has decreased to reach the first set voltage value, and causing a display to perform display under the control of the central processing unit; and A second set voltage detecting means for detecting that the voltage has reached the second set voltage value and stopping the measurement under the control of the central processing unit is provided.
[0009]
Accordingly, the battery voltage is first notified that the battery voltage has reached the first set voltage value, and the battery replacement operation can be prompted to the administrator, and the battery replacement can be promptly performed before the operation of the flowmeter stops. It can be carried out.
In addition, when the battery voltage reaches the second set voltage value that is the final voltage without replacing the battery, the measurement process of the flow meter is immediately stopped, and the measurement of the flow rate and the integration of the measured value are stopped. Thus, it is possible to prevent the integrated value of the flow rate at which the integration is restarted after the battery replacement from being damaged by the integrated value before reaching the second set voltage value.
[0010]
The flowmeter according to claim 2 of the present invention is configured such that the first set voltage value is a minimum voltage value that is supplied around the central processing unit and guarantees a normal flow measurement process. The flowmeter according to claim 1, wherein
Thus, when the voltage is equal to or higher than the first set voltage value, a correct measurement value by the flow meter can be guaranteed, and when the voltage is equal to or lower than the first set voltage value, a measure can be taken to promptly replace the battery. This first set voltage value can be set to an arbitrary value.
[0011]
The flowmeter according to claim 3 of the present invention is characterized in that the second set voltage value is a voltage value that is supplied around the central processing unit and makes it impossible to perform a normal flow rate measurement process. The flowmeter according to claim 1, wherein
Thus, the flow rate integrating operation can be continued while collecting the flow rate measurement value, although the reliability is lacking, until the second set voltage value is reached. It is possible to stop the accumulation of the flow measurement values. This second set voltage value can be set to any value.
[0012]
The flowmeter according to a fourth aspect of the present invention is the flowmeter according to the first aspect, wherein a display unit displays that the measurement processing of the normal flow rate becomes impossible.
As a result, it is possible to confirm that the integration of the flow rate measurement value having a remarkable measurement error has stopped, and to confirm that the measurement processing can be performed after the battery replacement.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a flow meter according to the present invention will be described in detail with reference to FIGS. FIG. 1 is a block diagram showing an embodiment of a flow meter according to the present invention, FIG. 2 is a discharge characteristic diagram of a battery according to the present invention, and FIG. 3 is a flowchart showing a procedure for detecting a battery voltage according to the present invention. Here, a gas flow meter will be described as an example.
As shown in FIG. 1, a flow rate measuring unit 2 as flow rate measuring means is attached to a pipe 1 of a gas as a fluid. The flow rate measuring unit 2 outputs a number of flow rate pulses according to the flow rate of the fluid that has passed through the pipe, for example, and supplies this to a CPU (Central Processing Unit) 3.
[0014]
Therefore, the CPU 3 calculates the flow rate of the gas based on the number of flow rate pulses and obtains the integrated value of the flow rate. The flow rate measuring unit 2 includes a rotating body that rotates in accordance with a gas flow rate flowing in the pipe 1 and a pickup that detects the rotation of the rotating body.
In addition, a flow sensor (a thermal micro flow sensor) or the like can be used as the flow rate detection unit 2. In this case, the CPU 3 obtains the flow rate from the flow velocity × cross-sectional area.
[0015]
Further, a battery 4 is provided for supplying power to each of the illustrated circuits (blocks) including the CPU 3. The CPU 3 has a first set voltage detecting means for detecting a first set voltage value of the battery 4. The first set voltage detecting circuit 5 is connected to a second set voltage detecting circuit 6 as a second set voltage detecting means lower than the first set voltage value.
[0016]
Here, the first set voltage value that is the first warning level is a minimum voltage value that guarantees a normal flow measurement operation, for example, 2.50 V, assuming that the battery voltage is 3 V, for example. On the other hand, the second set voltage value, which is the second warning level, is lower than the first set voltage value, so that a normal flow rate measurement operation cannot be performed, and a voltage value that causes a large error in the flow rate measured value. , For example, 2.48V.
[0017]
As shown in FIG. 2, the discharge voltage of the battery 4 gradually decreases with the discharge time. Then, the first set voltage value V1 and the second set voltage value V2 are set in a drooping curve portion of the discharge voltage, and based on these, the battery voltage is set to the first set voltage detection circuit 5 and the second set voltage value V2. It is constantly monitored by the set voltage detection circuit 6.
[0018]
The CPU 3 is connected to a data memory 7 composed of an EEPROM (Electrically Erasable Programmable Read Only Memory). The data memory 7 stores the gas flow rate immediately before the gas flow rate measurement is stopped or the integrated value of the gas flow rate. Functions to temporarily write and hold.
Therefore, even when the power supply is stopped, the data once written is retained without being erased.
[0019]
The CPU 3 has a data memory 8 such as a static RAM (Static Random Access Memory) for writing and reading a flow rate and an integrated value during measurement, and an erasure memory storing a program for executing an arithmetic process. A program memory 9 composed of a possible ROM (Read Only Memory) is connected.
[0020]
Further, a reset circuit 10 and a display 11 are connected to the CPU 3. After the operation of the flow meter is stopped, the reset circuit 10 replaces the battery and inputs a reset signal. When the reset signal is input, the gas flow value held in the data memory 7 is used as an initial value, and the newly measured flow value is used. Addition can be started.
The display 11 selectively displays the instantaneous flow rate during the flow rate measurement or during the stop of the measurement and the integrated value of the flow rate. For example, a liquid crystal display (LCD) is used. Although not shown, the CPU 3 is connected to a host computer of an information management department such as an information management center via a serial interface.
[0021]
The CPU 3 calculates the gas flow rate, obtains an integrated value of the gas flow rate, displays processing for displaying a warning due to a decrease in battery voltage, and integrates the fluid measurement value based on the input of the reset signal. It controls and executes a restart process, a process of writing and reading data to and from the data memory 7, a process of transmitting and receiving data to and from an external host computer, and the like.
Further, DC power (drive power) is supplied from the battery 4 to the flow rate measurement unit 2, the CPU 3, the set voltage detection circuits 5, 6, the data memories 7, 8, the program memory 9, the reset circuit 10, and the display 11. .
[0022]
Next, the operation of the flow meter having the above configuration will be described.
First, when the flow meter is used for the first time and a new battery 4 is used, the reset circuit outputs a reset signal when the power from the battery 4 is turned on, and the CPU 3 is started.
At this time, since the data memory 7 does not record data such as integrated data of gas flow values, the display 11 does not display the flow value or the integrated value of flow.
[0023]
Here, when a gas such as city gas or medical gas, which is a fluid, flows through the pipe 1, the flow rate measuring unit 2 outputs a flow rate pulse proportional to the flow rate of the fluid by, for example, the rotating body and the pickup. Is input to
The CPU 3 receives the flow rate pulse, accumulates the flow rate pulse according to a program stored in the program memory 9 according to a predetermined procedure, calculates the accumulation of the flow rate, stores the integrated flow rate in the data memory 8, and simultaneously displays the display 11 Displays the flow rate value and integrated value.
[0024]
On the other hand, during this flow rate measurement operation, the first set voltage detection circuit 5 and the second set voltage detection circuit 6 monitor the voltage value of the battery 4 that supplies power to each circuit component including the CPU 3. I have.
As shown in FIG. 3, the CPU 3 first determines whether or not the monitored voltage value has decreased to the first set voltage value V1 set in the first set voltage detection circuit 5 by the flow rate measurement operation. (Step S1).
[0025]
If the first set voltage value V1 has not been reached, the normal flow measurement is continued, and the flow value and the integrated value of the flow value are stored in the data memory 8.
On the other hand, when the voltage value drops to the level that reaches the first set voltage V1, the voltage drop is immediately displayed on the display 11 (Step S2), and a notification is transmitted from the transmitting unit (not shown) to the information management unit. Do.
The first set voltage value is a limit voltage value that guarantees the operation of the flow meter. The measurement result below this voltage value cannot maintain reliability because of the drooping characteristics of the battery voltage, but is not practical. Does not significantly affect measurement results. Therefore, the recording of the flow rate value and the integrated value of the flow rate in the data memory 8 is continued.
[0026]
Furthermore, if the display and the notification are left incorrectly, the flow measurement will be continued. At this time, the second set voltage detection circuit 6 monitors the voltage value of the battery 4, and determines whether the voltage value has decreased to a level reaching the second set voltage value V2. The circuit 6 makes a determination (step S3).
[0027]
If the voltage has not reached the second set voltage value V2, the CPU 3 continues the flow measurement processing based on the determination result. However, when the voltage value of the battery 4 reaches the second set voltage value V2 and further falls below this voltage value, the CPU 3 stops the measurement operation (step S4).
Therefore, the integrated data, which is the flow measurement value until the flow measurement operation is stopped, is transferred from the data memory 8 to the data memory 7 and stored, and the display 11 indicates that the measurement operation is stopped. Is done. This display can also be made by turning on or blinking a lamp or outputting sound, and is also notified to the information management department.
[0028]
In this way, when the voltage value of the battery 4 drops below the second set voltage value V2, the flow measurement operation is stopped, thereby preventing the output and display of an incorrect flow value and its integrated value. it can.
When the battery 4 is replaced with a new one in response to the notification and the flow rate measurement is restarted by operating the reset circuit, the integrated value written in the data memory 7 is transferred to the data memory 8, and On the basis of the integrated value, a flow measurement value which is measured normally again is integrated thereon.
Thus, the integrated value after the restart of the flow rate measurement can be made an accurate integrated flow rate. Thereafter, the same operation as described above is performed mainly by the CPU 3.
[0029]
In the above embodiment, the flow rate measurement using gas as a fluid has been mainly described. However, it goes without saying that the above-described configuration and operation can be adopted for flow rate measurement of a liquid such as water other than gas.
[0030]
【The invention's effect】
As described above, according to the flow meter of the present invention, the flow rate of the fluid is measured by the flow rate measuring means, the flow rate is calculated by the central processing unit based on the measurement result, and the first set voltage is detected by the detecting means. Detecting that the battery voltage has dropped to the first set voltage value, causing the central processing unit to display an advance notice of measurement stop on the display, and causing the second set voltage detection means to change the battery voltage to the second set voltage value. When the voltage drops to the set voltage value, the central processing unit stops the measurement operation, so that the battery replacement is promptly prompted to replace the battery, and the flow rate measurement value when the battery replacement timing is missed. By stopping the measurement and the integration, accurate retention and use of the flow rate data can be realized.
[0031]
Further, the first set voltage value is supplied to the central processing unit as a center and is set to the minimum voltage value that guarantees a normal flow rate measurement process. Correct measurement values can be guaranteed, and if the voltage is equal to or less than the first set voltage value, a measure for promptly prompting replacement of the battery can be taken.
[0032]
Further, by setting the second set voltage value to a voltage value that is supplied around the central processing unit and makes it impossible to perform a normal flow rate measurement process, until the second set voltage value is reached. The flow rate integrating operation can be continued while collecting the flow rate measurement value, which lacks reliability, and the measurement and integration of the incorrect flow rate value can be stopped after reaching the second set voltage value.
In addition, by displaying on the display that the normal flow rate measurement processing has become impossible, it is possible to confirm that accumulation of erroneous flow rate measurement values has stopped.
[Brief description of the drawings]
FIG. 1 is a block diagram showing one embodiment of a flow meter of the present invention.
FIG. 2 is a discharge characteristic diagram of a battery according to the present invention.
FIG. 3 is a flowchart showing a procedure for detecting a battery voltage according to the present invention.
[Explanation of symbols]
2 Flow rate measurement unit (flow rate measurement means)
3 CPU (Central Processing Unit)
4 Battery 5 First set voltage detection circuit (first set voltage detection means)
6. Second set voltage detection circuit (second set voltage detection means)

Claims (4)

A flow rate measuring means for measuring a flow rate of the fluid, a central processing unit which operates using a battery as a power source, and calculates a flow rate based on a measurement result by the flow rate measuring means; a first set voltage at which the voltage of the battery decreases and A first set voltage detecting means for detecting that the battery voltage has reached the value, and displaying an advance notice of measurement stop on a display device under the control of the central processing unit; And a second set voltage detecting means for detecting that the measurement has been reached and stopping the measurement under the control of the central processing unit. The flowmeter according to claim 1, wherein the first set voltage value is a minimum voltage value supplied around the central processing unit to guarantee a normal flow measurement process. 2. The flowmeter according to claim 1, wherein the second set voltage value is a voltage value supplied around the central processing unit so that a normal flow rate measurement process cannot be performed. 3. The flowmeter according to claim 1, wherein the display displays that the normal flow measurement processing has become impossible.

Images