JP2001027554A - Method and device for generating flowrate pulse and/or electronic-type gas meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain flowrate pulse generation method and device and/or an electronic-type gas meter that can generate a flowrate pulse with a period according to the passing volume of gas without shortening a sampling period. SOLUTION: Every time when a calculation means 14a-1 intermittently calculates passing volume at a fixed period, a calculation means 14a-2 calculates the 1/N value of the passing volume. Until an integrating means 14a-3 integrates the 1/N value for N times, a counter means 14a-4 repeatedly counts the number of times of integration where an integration value reaches unit passing volume/2 or more. Until the integration is made for N times, every time when the unit passing volume/2 is reached, a subtraction means 14a-5 repeatedly subtracts the value of the unit passing volume/2 from the integration value. A decision means 14a-6 multiplies the number of integration times by a fixed period, 1/N, for determining an output reversal timing to the next. A pulse generation means 14a-7 reverses output at the decision timing for generating the flowrate pulse of a period corresponding to the passing volume.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a physical quantity which varies according to a gas flow rate intermittently, that is, at a sampling period, and obtaining a gas flow rate from the measured physical quantity. The present invention relates to a method and an apparatus for generating a flow pulse which generates a flow pulse corresponding to a unit passing volume of a gas in accordance with a passing volume calculated by multiplying an instantaneous flow by an intermittent time. The present invention further provides an electronic type having a built-in weighing display unit for integrating and displaying the passing volume measured by the flow pulse generator and a security logic unit for detecting a gas flow abnormality by the flow pulse generated by the flow pulse generator. It relates to a gas meter.

[0002]

2. Description of the Related Art In a conventional membrane gas meter, there is provided a switching device comprising two chambers separated by a diaphragm comprising a diaphragm, and a slide valve for alternately connecting each of the two chambers to a gas inlet and a gas outlet. It has a structure including a valve, and a connecting mechanism that connects the diaphragm and the switching valve, transmits the movement of the diaphragm to the switching valve, and drives the switching valve. In this gas meter, when the gas pressure at the gas outlet decreases due to gas consumption or the like on the downstream side of the gas meter, a pressure difference is generated between the gas inlet and the gas outlet, and one of the gas meters is connected to the gas inlet. The gas flows into the chamber, and the gas flows in the chamber, whereby the diaphragm moves and the gas in the other chamber connected to the gas outlet is discharged. When the diaphragm moves so that sufficient gas flows into one room and gas in the other room is sufficiently exhausted, the movement of the diaphragm is transmitted to the switching valve via the connection mechanism to drive the switching valve. One room connected to the gas inlet is connected to the gas outlet, and the other room connected to the gas outlet is connected to the gas inlet.

[0003] Therefore, after that, gas flows into the other room,
The gas in one room will be exhausted. Further, driven by power obtained from the middle of the coupling mechanism, the diaphragm makes one revolution in response to one reciprocation of the diaphragm to discharge a predetermined amount of gas.
An S-pole magnetized magnet is attached, and the reed switch is turned on and off by one rotation of this magnet to generate a flow pulse. That is, the flow sensor is constituted by the magnet and the reed switch which rotate in conjunction with the reciprocation of the diaphragm. Further, the gas meter has a built-in security logic unit that monitors a gas flow based on a flow pulse from the flow sensor described above, detects an abnormality thereof, and executes various security functions to prevent a gas accident.

The flow rate pulse generated by the above-mentioned flow rate sensor detecting the gas flow rate is generated every time the diaphragm makes one reciprocation and weighs a unit weighing volume of 0.7 L, for example.
The cycle of the flow rate pulse becomes shorter as the gas flow rate becomes larger, and becomes longer as the gas flow rate becomes smaller. The security logic unit using the flow rate pulse measures the cycle from the previous pulse every time each pulse of the flow rate pulse is input, obtains the gas flow rate, performs logic processing based on the gas flow rate, and performs security processing. To fulfill the function.

[0005] Recently, the above-mentioned membrane gas meter involves a mechanical operation, so that its structure is complicated and its size is limited, and there is a problem in terms of life. Various electronic gas meters have been proposed. What is common to these is that the gas flow velocity is obtained by measuring a physical quantity that changes according to the velocity of the gas flow, the instantaneous flow rate is obtained from the obtained flow velocity and the cross-sectional area of the flow path, and this instantaneous flow rate is integrated. Then, the passing volume is calculated, and the passing volume is integrated to obtain an integrated flow rate. For example, an ultrasonic flow sensor utilizes the fact that the transmission time of an ultrasonic wave varies depending on the speed of a gas flow, and intermittently emits an ultrasonic wave in a gas flow to measure the arrival time. The flow velocity is measured, the instantaneous flow rate is obtained by multiplying the measured flow velocity by the area of the flow path, and the passing flow rate is calculated by multiplying the instantaneous flow rate by the intermittent time.

Therefore, to obtain only the function of obtaining the integrated flow rate of the gas meter, as described above, the instantaneous flow rate is obtained from the flow velocity and the sectional area of the flow path, and this instantaneous flow rate is integrated to obtain the integrated flow rate. However, from the viewpoint of the labor of development and reacquisition of safety standards,
When using a conventional security logic unit, a function to output a flow pulse with a period corresponding to the passage volume to the flow measurement unit that calculates the passage volume based on the physical quantity measured by the output of the flow sensor Need to be added.

By the way, when a flow rate of 40 (L / pulse) is output at a flow rate of 100 (m ³ / h),
The signal frequency of the flow pulse is 0.694 Hz (the period is 1.
However, in order to accurately output the flow rate pulse, the ultrasonic sensor must emit ultrasonic waves and measure the flow velocity, that is, the sampling cycle must be 1.44 seconds or less. This is because, when an attempt is made to output a flow pulse having a cycle reflecting the gas flow velocity or the gas flow rate, the measurement must be completed before the output cycle comes. For this reason, when a flow rate of 100 (m ³ / h) or more is considered, the sampling cycle in the flow rate measuring unit becomes infinitely short.

[0008]

As described above, in the case where sampling is performed every time a flow pulse is generated, when a flow pulse having a short cycle is generated,
It is necessary to shorten the sampling cycle accordingly. For example, in an ultrasonic flow sensor, signal processing must be performed by emitting ultrasonic waves every sampling, which increases power consumption and uses a battery as a power source. It becomes difficult to apply the above-described flow pulse generating method and apparatus to a gas meter.

In view of the above, the present invention provides a flow pulse capable of generating a flow pulse corresponding to a unit passage volume of a gas having a cycle corresponding to the gas passage volume without shortening a sampling period. It is an object to provide a generation method and an apparatus.

The present invention also provides a flow pulse generating apparatus capable of generating a flow pulse corresponding to a unit passage volume of a gas having a cycle corresponding to a gas passage volume without shortening a sampling period, An object of the present invention is to provide an electronic gas meter having a security logic unit using a flow pulse generated by a generator.

[0011]

According to a first aspect of the present invention, there is provided an apparatus for calculating a passing volume intermittently at a constant period, and each time the passing volume is calculated, the calculated passing volume is calculated. The 1 / N value of the volume is calculated, the calculated 1 / N value is sequentially integrated with the previous integrated value, and each time the integrated value becomes equal to or more than の of the unit passing volume, the number of times of integration is obtained. The subtraction of 1/2 of the unit passage volume from the integrated value is repeated until the 1 / N value is integrated N times, and the timing of inverting the output by multiplying the integrated number by 1 / N of the predetermined period is determined. A flow pulse generating method is characterized in that the flow pulse is determined and the output is inverted at the determined timing to generate a flow pulse corresponding to a unit passing volume of the gas having a cycle corresponding to the passing volume.

According to the procedure of the flow pulse generating method according to the first aspect, 1/1 of the passing volume calculated intermittently at a constant cycle.
For each calculation, the N value is calculated as 1 / N value of the calculated passing volume, and the calculated 1 / N value is sequentially integrated with the integrated value before it, and the integrated value is calculated as 1 / N of the unit passing volume. Every time it becomes 2 or more, the number of times of integration is obtained, and the subtraction of １ ／ of the unit passage volume from the integrated value is repeated until the 1 / N value is integrated N times. The output is inverted at a timing determined by multiplying the number of integration times by 1 / N of a certain cycle, and a flow pulse corresponding to a unit passing volume of the gas having a cycle corresponding to the passing volume is generated.

As described above, when the calculated passing volume is small, the 1 / N value becomes small, and the integrated value does not become １ ／ or more of the unit passing volume, and until the next passing volume is calculated. The timing for inverting the output is not determined. Also, when the passing volume is large, the 1 / N value increases, and the integrated value becomes 1/2 or more of the unit passing volume multiple times, and the output is inverted until the next passing volume is calculated. A plurality of timings are determined. Therefore, when the integrated passing volume is small, that is, when the flow rate is small, the flow pulse is not output even with the passing volume calculated once intermittently, and when the integrated passing volume is large, that is, when the flow rate is large, one time intermittent pulse is output. A plurality of flow pulses that are inverted every 1/2 of the unit passing volume will be output even with the calculated passing volume, so even if the passing volume is large, the intermittent passing volume calculation cycle should be shortened. That is, a flow pulse corresponding to a unit passing volume of gas having a cycle corresponding to the passing volume can be generated without shortening the sampling cycle. In addition, since the flow pulse is inverted every half of the unit passage volume, that is, every half of the integrated value, the unit passage volume can be detected from the rise or fall to the fall or rise of the flow pulse.

A second aspect of the present invention has been made to solve the above problems.
The disclosed invention is, as shown in the basic configuration diagram of FIG. 1, a passing volume calculating means 14 for calculating a passing volume intermittently at a constant period.
a-1; 1 / N calculating means 14a-2 for calculating a 1 / N value of the passing volume each time the passing volume is calculated by the passing body integrating means; and 1 / N value is sequentially integrated. With the integrating means 14a-3, until the 1 / N value is integrated N times,
An integration number counting means 14a-4 for repeating counting the number of integrations until the integrated value by the integrating means becomes equal to or more than １ ／ of the unit passage volume; and the integration until the 1 / N value is integrated N times. A subtracting means 14a-5 for repeating a subtraction of a half of the unit passage volume from the integrated value each time the value becomes a half of the unit passage volume; N, multiplying by N, the timing determining means 14a-6 for determining the timing of inverting the output until the passing volume is next calculated by the passing volume calculating means, and inverting the output at the timing determined by the timing determining means. And a pulse generating means 14a-7 for generating a flow pulse corresponding to a unit passing volume having a cycle corresponding to the passing volume.

According to the second aspect of the present invention, the passing volume calculating means 14a-1 intermittently calculates the passing volume at a fixed period, and every time the calculation is performed, the 1 / N calculating means 14a-1 is used.
a-2 calculates the 1 / N value of the passage volume. Integrator 14
Until a-3 integrates the 1 / N value sequentially and integrates the 1 / N value N times, the integrated value by the integrating means is １ ／ of the unit passage volume.
The cumulative number of times until the above is reached is calculated by the cumulative number counting means 14a-
4 repeats counting. Until the 1 / N value is integrated N times, each time the integrated value becomes one half of the unit passage volume, the subtraction means 14a-5 calculates 1 / N of the unit passage volume from the integrated value.
The subtraction of 2 is repeated. The timing determining means 14a-6 multiplies the number of integration times 1 / N of a certain period, and determines the timing of inverting the output until the passing volume calculating means next calculates the passing volume. Pulse generating means 14a-
7 inverts the output at the timing determined by the timing determining means and generates a flow pulse corresponding to a unit passing volume of a cycle corresponding to the passing volume.

As described above, when the calculated passing volume is small, the 1 / N value becomes small, and the integrated value does not become １ ／ or more of the unit passing volume, and until the next passing volume is calculated. The timing for inverting the output is not determined. Also, when the passing volume is large, the 1 / N value increases, and the integrated value becomes 1/2 or more of the unit passing volume multiple times, and the output is inverted until the next passing volume is calculated. A plurality of timings are determined. Therefore, when the integrated passing volume is small, that is, when the flow rate is small, the flow pulse is not output even with the passing volume calculated once intermittently, and when the integrated passing volume is large, that is, when the flow rate is large, one time intermittent pulse is output. A plurality of flow pulses that are inverted every 1/2 of the unit passing volume will be output even with the calculated passing volume, so even if the passing volume is large, the intermittent passing volume calculation cycle should be shortened. That is, a flow pulse corresponding to a unit passing volume of gas having a cycle corresponding to the passing volume can be generated without shortening the sampling cycle. In addition, since the flow pulse is inverted every half of the unit passage volume, that is, every half of the integrated value, the unit passage volume can be detected from the rise or fall to the fall or rise of the flow pulse.

According to a third aspect of the present invention, in the flow rate pulse generator according to the second aspect, the timing determination means stores a time obtained by multiplying the integration number by 1 / N of the predetermined period. Means 14c-1; and timer means 14c-2 for sequentially reading and storing the time stored in the time storage means. The passing volume calculation means determines the time when the timer means measures the read time. The flow rate pulse generator is characterized in that the flow volume is determined as the timing of inverting the output until the next calculation of the passing volume.

According to the flow rate pulse generator of the third aspect, the time storage means 14c-1 stores the number of times of integration in the fixed period of one.
/ N is stored, and the timer means 14c-
2 is sequentially read and timed, and the time when the timer means reads the time is determined as the timing for inverting the output until the passed volume calculation means next calculates the passed volume. When there is an integrated value immediately before calculating the volume, the number of integrations is 1 reflecting the previous integrated value.
The number of times of integration of the / N value is small, and the number of integrations thereafter is large. Therefore, the time storage unit 14c-1 may store a plurality of times obtained by multiplying the number of times of integration by 1 / N of a certain period, but the timer unit 14c-2 sequentially reads the stored times. It can be converted into a flow pulse corresponding to a unit passing volume of gas having a cycle corresponding to the passing volume of gas and output.

According to a fourth aspect of the present invention, there is provided a flow pulse generating apparatus according to the second or third aspect, and a passing volume integrating means for integrating the passing volume obtained by the passing volume calculating means of the flow pulse generating apparatus. And a display means 15 for displaying the passing volume integrated by the passing volume integrating means, and a security logic means 20 for detecting a gas flow abnormality by a flow pulse generated by the flow pulse generator. It exists in electronic gas meters.

According to the electronic gas meter of the present invention, the flow rate pulse generator generates the flow rate pulse having a cycle corresponding to the passing volume. Anything that detects abnormalities can be used.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an electronic gas meter 1 incorporating a device for implementing the flow pulse generating method according to the present invention and a flow measuring device. The illustrated electronic gas meter 1 has a flow rate measurement unit 100 and a security logic unit 20.

The flow rate measuring section 100 intermittently measures a physical quantity that changes according to the gas flow velocity, that is, at a sampling cycle, obtains a gas flow velocity based on the measured physical quantity, and determines the flow velocity and the cross-sectional area of the flow path. And the instantaneous flow rate is multiplied by the intermittent time to obtain a passing volume. The obtained passing volume generates a flow pulse corresponding to the unit passing volume of the gas. To be supplied. Security Logic 2
0 detects an abnormality in the gas flow by the flow pulse from the flow measurement unit 100.

The ultrasonic flow meter shown in FIG. 3 will be described below as an example of the flow measuring unit 100. The ultrasonic flow rate measuring unit 100 is operated at an ultrasonic frequency which is disposed opposite to each other at a distance L in a gas flow direction in a gas flow path 10 as a flow path in a gas meter for flowing gas. Acoustic transducers T composed of a piezoelectric vibrator
Void 10a communicating with D1 and TD2 and gas flow path 10
And a sound transducer TD3 disposed opposite to the tube wall 10b separated by a distance l. Gas flow path 10
Is provided with a shutoff valve 10c upstream of the two acoustic transducers TD1, TD2 to shut off the gas flow path 10 by closing the valve.

Each transducer TD1, TD2, T
D3 is connected to a transmission circuit 12 and a reception circuit 13 via transducer interface (I / F) circuits 11a and 11b, respectively. The transmission circuit 12 transmits a signal for generating an ultrasonic signal by driving one of the transducers TD1 and TD2 under the control of a microcomputer (μCOM) 14 in the form of a pulse burst. (Not shown). The receiving circuit 13 has a built-in preamplifier (not shown) that receives signals from the other transducers TD1 and TD2 that have received the ultrasonic signals that have passed through the gas flow path 10 and that processes the ultrasonic signals. . Regarding the transducer TD3, the μCOM 14 controls the transmission circuit 12 and the reception circuit 13 at a timing different from that for the transducers TD1 and TD2, and controls the transmission circuit 12 so as to drive the transducer TD3 to generate an ultrasonic signal. ,
The same transducer TD3 receives the ultrasonic signal reflected from the tube wall 10b and controls the receiving circuit 13 so as to input a signal generated.

The μCOM 14 is connected to a telephone line which is a public communication network via a MODEM (modulation / demodulation circuit) 18 and an NCU (network control unit) 19, and performs communication processing for performing communication with a remote management center. It has become.

As shown in FIG. 4, the μCOM 14 is a read-only memory (RO) storing a central processing unit (CPU) 14a for performing various processes in accordance with programs, a program for processing performed by the CPU 14a, and the like.
M14b, RA which is a readable and writable memory having a work area used in various processing steps in the CPU 14a, a data storage area for storing various data, and the like.
M14c, etc., which are interconnected by a bus line 14d.

The CPU 14a in the μCOM 14 performs control to alternately switch between a transducer for supplying a signal from the transmission circuit 12 and a transducer for receiving an ultrasonic signal in the reception circuit 13, and also controls transmission and reception between the two transducers alternately. In addition to the flow velocity calculation processing for intermittently calculating the flow velocity of the gas flowing in the gas flow path 10 by measuring the propagation time of the sound wave signal, based on the calculated flow velocity and the cross-sectional area of the gas flow path 10 Flow rate calculation processing for calculating the instantaneous flow rate, passing volume calculation processing for calculating the passing volume by multiplying the calculated instantaneous flow rate by the intermittent time, passing volume integration processing for integrating the calculated passing volumes to obtain an integrated passing volume, and passing volume integration Display 1 shows the integrated value of the passing volume obtained by the processing.
Then, a display process to be displayed on the display 5 is performed. These are related to the original function as a gas meter. In addition, μC
The CPU 14a in the OM 14 performs a flow rate pulse generation process of generating a flow rate pulse corresponding to a unit gas flow rate at the output port O using the calculated flow volume.

The principle of the flow rate measurement for working as the gas meter described above will be described below. The CPU 14a included in the μCOM 14 outputs a trigger signal to the transmission circuit 12 to generate a pulse burst signal, and supplies the pulse burst signal to one of the transducers TD1 and TD2 to generate an ultrasonic signal at the one transducer. The receiving circuit 13 receives the signal from the other transducer that receives the ultrasonic signal transmitted from one of the transducers, and takes in the signal generated by the receiving circuit 13 in response to the signal. Then, the CPU 14a built in the μCOM 14
Performs control to repeat the same operation once again by reversing the transducer that generates the ultrasonic signal and the transducer that receives the ultrasonic signal. And C of μCOM14
The PU 14a outputs a trigger signal to the transmission circuit 12, generates an ultrasonic signal in one of the transducers, and captures a signal generated by the other transducer that receives the ultrasonic signal through the reception circuit 13 through the reception circuit 13. T
1 and T2 are measured, and the flow rate of the gas flow is obtained from the measured times T1 and T2 as described later.

The CPU 14a of the μCOM 14 controls the transducer TD3 at a different timing from the control of the transducers TD1 and TD2, outputs a trigger signal to the transmitting circuit 12, and generates a pulse burst signal. The transducer TD3
To generate an ultrasonic signal in the transducer TD3. Further, the receiving circuit 13 receives a signal from the same transducer TD3 that receives the ultrasonic signal transmitted from the transducer TD3 and reflected by the tube wall 10b, and takes in the signal generated by the receiving circuit 13 in response to the signal. Then, the CPU 14a outputs a trigger signal to the transmission circuit 12 to cause the transducer TD3 to generate an ultrasonic signal, and to reflect the first wave and the second wave of the reflected ultrasonic signal.
The time Tr1 until the signal generated by the same transducer TD3 for receiving the wave is taken in through the receiving circuit 13,
Tr2 was measured, and the measured times Tr1, Tr2
Thus, the sound velocity in an atmosphere having the same temperature, pressure, and gas type as in the gas flow path 10 but no gas flow is obtained as described later.

Now, the propagation speed of sound in a stationary gas (sound speed)
Is c, and the flow velocity of the gas flow is v, the propagation velocity of the ultrasonic signal in the forward direction of the gas flow is (c + v). Assuming that the distance between the transducers TD1 and TD2 is L, the time T1 at which the ultrasonic signal from the transducer TD1 travels in the same direction as the gas flow and reaches the transducer TD2;
The time T at which the ultrasonic signal from the transducer TD2 travels in the opposite direction to the gas flow and reaches the transducer TD1.
T1 = L / (c + v) (1) T2 = L / (cv) (2) From equations (1) and (2), v = (L / 2) · (1 / T1-1 / T2) = (L / 2) · ((T2−T1) / (T2 · T1)) (3) , L are known, the flow velocity v can be obtained by measuring T1 and T2.

Note that T2 · T1 = L / (c + v) · (c
−v) = L / (c ² −v ² ), and the flow velocity v is an extremely small value compared to the sound velocity c, so v ^{2 in} the equation is c ²
Is extremely small and can be neglected, and T2 · T1 = L / c ² . Then, the above equation (3) can be finally rewritten as v = ((T2−T1) · c ² ) / 2 = (T2−T1) · (c ² ) · (１ ／). Here, Td = (T2-T
When 1), v = Td · ( c 2/2) = Td · k (4) where a k = c ^2/2.

When the flow velocity v is obtained, the instantaneous flow rate Q
Assuming that i is a known cross-sectional area of the gas flow path 10 and α is a correction coefficient that changes depending on the structure of an object or the like, Qi = Td · α · S · k = K · Td (5), and the instantaneous flow rate Qi becomes Desired. Here, K = α · S · k (6). Note that K is a coefficient for correction including many factors such as sound speed, gas temperature, and gas pressure, as is apparent from the above description.

The sound velocity c in the stationary gas in the equation (6) communicates with the gas flow path 10 as shown in FIG. 3, but is not affected by the gas flow in the gas flow path 10. In the space 10a of the stationary gas, the time until the ultrasonic signal emitted from the third acoustic transducer TD3 is reflected on the inner surface of the tube wall 10b and returns to the transducer is measured. The sound velocity c can be obtained by dividing the reciprocating distance 2l to the pipe wall 10b, and the sound velocity c obtained by appropriately performing this measurement may be used.

Therefore, every time the instantaneous flow rate Qi is obtained, that is, every time sampling is performed, the flow volume Qt is multiplied by the elapsed time (time of the sampling interval) from the last time obtained (sampled) to obtain the flow volume Qt. By calculating and integrating this, the integrated volume Qs integrated, that is, the gas supply amount (gas usage amount) can be obtained. Then, this integrated passage volume Q
By displaying s on the display 15, an electronic gas meter can be configured.

Next, a process in which the CPU 14a outputs a flow rate pulse corresponding to the unit passing volume of gas to the output port O using the calculated passing volume will be described below.

In the flow rate measuring process, the CPU 14a multiplies the instantaneous flow rate obtained by multiplying the flow rate of the gas, which is a physical quantity, which is sampled and measured at every elapse of a fixed period of sampling time, by the sectional area of the flow path, and multiplies the time of the sampling interval. By performing the calculation, the gas volume that has passed during the sampling interval is calculated as the passing volume. The calculated passing volume is temporarily stored in a passing volume storage means formed in a predetermined area of the RAM 14c. Next, the 1 / N value is calculated by dividing the passing volume temporarily stored in the passing volume storing means by 1 / N, and this is formed in another predetermined area of the RAM 14c.
/ N value storage means.

Subsequently, the calculated 1 / N values are successively integrated. If there is no integrated value to be pulse-output before that, the sequentially integrated 1 / N value is equal to the predetermined unit passing flow rate of 2
The integrated value is calculated by counting the number of times of integration until it becomes a value equal to or smaller than 1/2, that is, 1/2 or more, and subtracting 1/2 of the unit passage flow rate from the integrated value to set the integrated value to 0.
It repeats until N value is integrated N times. If there is an integrated value to be pulse output before that, the 1 / N value is sequentially integrated into the integrated value, and the 1 / N value sequentially integrated is a value that is a half of a predetermined unit passing flow rate. In other words, the number of times of integration until it becomes 1/2 or more is obtained, and the value of 1/2 of the unit flow rate is subtracted from the integrated value to make the integrated value 0, and this process is repeated until the 1 / N value is integrated N times. repeat. It should be noted that the sequentially integrated 1 / N value is 1 / N of a predetermined unit passing flow rate.
Each time the number of times of integration up to 2 or more is obtained, this is temporarily stored in an integrated number of times storage means formed in another predetermined area of the RAM 14c, and is used to determine the timing of inverting the output thereafter.

After that, the integration time stored in the integration number storage means is added to the sampling period of a fixed period, that is, 1 of the sampling period obtained by dividing the sampling period by N.
/ N to determine the timing of inverting the output. For this purpose, the times obtained by multiplying by 1 / N of the sampling period are temporarily stored in time storage means formed in another predetermined area of the RAM 14c, and the times stored in the time storage means are sequentially read out. And R
The time is measured by timer means formed in another predetermined area of the AM 14c. Then, the point in time when the time read by the timer means is measured is determined as the timing of inverting the output until the next calculation of the passing volume.

As described above, the number of times of integration until the integrated value obtained by sequentially integrating the 1 / N values calculated after sampling at a fixed period becomes equal to or more than １ ／ of the unit passing flow rate is determined, and the unit passing flow rate is determined from the integrated value. This process is repeated until the value of 1/2 of the flow rate is subtracted and the 1 / N value is integrated N times.
When the number of times of integration is multiplied by 1 / N of the sampling period to determine the timing of inverting the output, and when the value of the passing volume is a value corresponding to one or more unit passing volumes forming the flow rate pulse, Thus, it is possible to output a flow pulse composed of pulses having a cycle corresponding to the magnitude thereof.

The flow rate pulse generated by the above-described flow rate pulse output processing is input to the security logic unit 20. As shown in FIG. 5, the security logic unit 20 includes a central processing unit (CPU) 21a that performs various types of processing according to a program, similarly to the μCOM 14 of the flow rate measurement unit 10 in FIG.
ROM 21b, which is a read-only memory storing a program for processing performed by the memory 21a, a work area used in various processing steps in the CPU 21a, and a RAM 21c which is a readable and writable memory having a data storage area for storing various data. Bus line 21
formed by μCOM21 interconnected by d.

ΜCOM 2 forming the security logic unit 20
The CPU 14a in 1 performs processing for each pulse forming the flow rate pulse input from the flow rate measuring unit 10, and installs the gas meter in one of the functions executed by the security logic, for example, the total flow rate cutoff function. If the total gas consumption of the preceding combustion appliance exceeds the shutoff value automatically set by learning, it is determined that a large amount of gas leaks due to erroneous opening of the main valve or disconnection of the rubber hose, so that the shutoff valve 10c is closed and the gas is released. Cut off. In the increased flow rate cutoff function, if the flow rate of the gas increases, and if the flow rate of the combustion equipment at the installation location is abnormally large compared to the gas equipment that consumes the largest amount, if the main plug is accidentally opened or the rubber hose is When it is determined that the gas leaks due to slippage or the like, a safety operation such as closing the shutoff valve 10c to shut off gas is performed. When any alarm is issued by the security operation, an alarm is generated by the sounding device or indicator of the alarm unit 22. Further, when an alarm is notified to a remote management center, the remote management center is connected to a telephone line as a public communication network via a MODEM (modulation / demodulation circuit) 18 and an NCU (network control unit) 19. Communication processing for performing communication is also performed.

The general operation of the electronic gas meter has been described above. The operation of the flow rate pulse generator will now be described in detail with reference to the flow chart of FIG. 6 showing the flow rate pulse output processing performed by the CPU 14a.

The CPU 14a performs a flow rate pulse output process as a part of the flow rate measurement process, determines in a first step S1 whether or not the sampling time has elapsed, and waits for the sampling time to elapse. During this waiting time, the low power mode is entered. Then, when the sampling time has elapsed, the process proceeds to step S2 to execute sampling. The sampling includes the ultrasonic wave emission processing, the ultrasonic wave emission processing, the reception processing, and the processing for calculating the ultrasonic wave propagation time in the above-described ultrasonic flow measurement processing. Next, the process proceeds to step S3, where the passage volume is calculated by multiplying the instantaneous flow rate obtained from the gas flow rate measured by performing the sampling by the sampling time.

The passing volume of gas passing during the sampling interval calculated in step S3 is stored in the RAM 14
c is temporarily stored in the passing volume storage means formed in the predetermined area. Next, proceeding to step S4, the accumulated number i, which is the count value of the accumulated number counter means formed in the predetermined area of the RAM 14c, is cleared to 0, and the inverted number j, which is the count value of the inverted number counter means, is also cleared. To 0. Then, the process proceeds to step S5, where the RAM 14
After integrating the value of 1 / N of the passing volume, that is, 1 / N value, into the integrated value of the integrated value storage means formed in the predetermined area c, the process proceeds to step S6.

In step S6, the above step S
In step 5, it is determined whether the integrated value of the integrated value storage means after integrating the 1 / N value is equal to or more than half of the unit passage volume, that is, not less than ２. If the determination in step S6 is NO, The process skips steps S7 and S8 and proceeds to step S9. In step S9, the count i of the count of the count counter is incremented, and the process proceeds to step S10 to determine whether the count i is equal to N. When the determination in step S10 is NO, the process returns to step S5, and the value of 1 / N of the passing volume, that is, the 1 / N value is integrated with the integrated value of the integrated value storage means formed in the predetermined area of the RAM 14c, and step S6 is performed. Proceeds to step S7 when the determination in step S6 is YES.

In step S7, the integration time i, which is the count value of the integration number counter means at that time, is reduced by 1 / N the sampling time (sampling time /
N) is stored in a reversal timing storage means formed in a predetermined area of the RAM 14c as a j-th reversal timing time t (j) at that time.
For example, when j = 0, t (0), and when j = 1, t (0)
Stored as (1). In step S7, the number of inversions j, which is the count value of the inversion number counter formed in a predetermined area of the RAM 14c, is incremented. Then, the process proceeds to step S8, in which the value of の of the unit passage volume is subtracted from the integrated value of the integrated value storage means formed in the predetermined area of the RAM 14c, and then the step S10 is performed.
Proceed to.

When the determination in step S10 is YES, that is, when the integration number i, which is the count value of the integration number counter means, is equal to N, the process proceeds to step S11, where the count of the inversion number counter means formed in a predetermined area of the RAM 14c is counted. It is determined whether or not the value of the number of inversions j is 0. If the determination in step S11 is YES and the 1 / N value of the passing volume is less than の of the unit passing volume even when the 1 / N value of the passing volume is integrated N times, it is determined that there is no gas volume in the passing volume for which a flow pulse should be generated. And waits for the elapse of the sampling time to perform the next sampling. During this standby mode, the low power mode is set.

When the determination in step S11 is NO,
When 1 / N value of the passing volume is integrated N times, the reversal number j, which is the count value of the reversal number counter means, becomes 1 or more, and at least one time becomes 1/2 or more of the unit passing volume. And proceeds to step S12, RAM
After clearing the count value J of the inversion execution counter means for counting the number of times the output is actually inverted formed in the predetermined area 14c to 0, the process proceeds to step S13. In step S13, the inversion timing t time (j) corresponding to the value of the count value J of the inversion execution counter means is read, and the timing of the read inversion timing time is stored in the RAM.
After the timer means formed in the predetermined area 14c is started, the process proceeds to step S14.

In step S14, it is determined whether or not the inversion timing t time (j) has elapsed, and the process waits until the time has elapsed. During this waiting time, the low power mode is entered. When the time has elapsed, the process proceeds to step S15 to invert the output and increment the count value J, and then proceeds to step S16 to determine whether the count value J for counting the number of times the output is actually inverted is equal to the number of inversions i. Determine whether or not. If the determination in step S16 is NO, the process returns to step S13 to read the next inversion timing t time (j) corresponding to the incremented count value J, and repeats steps S14 to S16 until the determination in step S16 becomes YES. Execute repeatedly. If the determination in step S16 is YES, the process returns to step S1 and waits for the next sampling.

If there is an integrated value in step S5 in which the determination in step S6 is not YES, 1 / N of the passing volume calculated by the next sampling is added to the remaining integrated value. Thus, a flow pulse reflecting the passing volume calculated by the successive sampling is output for each unit passing volume. Also, the output flow pulse has a long cycle when the passing volume is small, and has a short cycle when the passing volume is large.

As is clear from the description given in accordance with the flowchart of FIG. 6, the CPU 14a serves as a passing volume calculating means 14a-1 for calculating the passing volume intermittently at regular intervals, each time the passing volume is calculated. As 1 / N calculating means 14a-2 for calculating 1 / N value of volume, as integrating means 14a-3 for sequentially integrating 1 / N values, the integrated value passes through a unit until the 1 / N value is integrated N times. As an integration frequency counting means 14a-4 that repeats counting the number of integrations until it becomes 1/2 or more of the volume, the integration value is reduced to one half of the unit passage volume until the 1 / N value is integrated N times. As the subtraction means 14a-5 repeats subtraction of a half of the unit passing volume from the integrated value every time the number of integrations is multiplied by 1 / N of a fixed period (sampling time), the passing volume is calculated next. Output until As the timing determination unit 14a-6 to determine the inverted timing pulse generating means 14 for generating a flow pulse corresponding to a unit passing volume of the period according to the passing volume inverts the output at the determined timing
As a-7, they function as passing volume integrating means 14a-8 for integrating the obtained passing volumes.

The RAM 14c has a time storage means 14c-1 for storing a time obtained by multiplying the number of integration times by 1 / N of a predetermined period (inversion timing), and a timer means 14c for sequentially reading out and storing the stored time. -2.

According to the flow rate pulse generator described above, as is apparent from FIG. 7 showing the relationship among the flow rate, the sampling timing, the integrated value, and the output inversion timing, the passing volume from the previous sampling is calculated for each sampling. Then, when the calculated passage volume is divided by N and integrated until the next sampling at the divided timing of N,
The output is inverted by calculating the timing exceeding 1/2 of the unit passing volume. The integrated value is 1 of the unit passing volume for each output reversal.
/ 2 is subtracted. Further, the CPU 14a reads the output of the flow velocity sensor every sampling time, performs the above-described processing, and then enters the power saving standby mode until the time when the output is inverted.

In the above-described embodiment, an ultrasonic sensor is used as an example of the flow sensor. However, the present invention is equally applicable to non-ultrasonic sensors that measure a physical quantity that changes according to the gas flow rate by sampling. can do.

[0055]

As described above, according to the first aspect of the present invention, even when the passing volume is large, the calculation cycle of the intermittent passing volume is not shortened, that is, the sampling cycle is shortened. Flow pulse corresponding to the unit passage volume of the gas having a cycle corresponding to the passage volume, so that a flow pulse generation method with low power consumption can be obtained.
The unit passing volume can also be detected from the rise or fall of the flow pulse to the fall or rise.

Further, according to the second aspect of the present invention, even when the passing volume is large, the intermittent passing volume calculation cycle is not shortened, that is, without reducing the sampling cycle, the passing volume is reduced. It is possible to generate a flow pulse corresponding to a unit passing volume of gas in a corresponding cycle. Also, since the flow pulse is inverted every half of the unit passage volume, that is, every half value of the integrated value, a flow pulse generator capable of detecting the unit passage volume from the rise or fall to the rise or fall of the flow pulse. Is obtained.

According to the third aspect of the present invention, a plurality of times obtained by multiplying the number of times of integration by 1 / N of a certain cycle may be stored, but the stored times are sequentially read out and timed. Flow pulse generation that can generate a flow pulse with an accurate period according to the passing volume because it can be converted into a flow pulse corresponding to the unit passing volume of the gas and output with a cycle corresponding to the passing volume of the gas. A device is obtained.

According to the fourth aspect of the present invention, it is possible to use a means for detecting an abnormality in the gas flow by the period of each pulse of the flow rate pulse as the security logic means, from the viewpoint of labor for development and reacquisition of safety standards. An advantageous electronic gas meter is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of a flow pulse generator and an electronic gas meter according to the present invention.

FIG. 2 is a block diagram showing one embodiment of an electronic gas meter according to the present invention.

FIG. 3 is a diagram showing a specific configuration of each unit in FIG. 2;

FIG. 4 is a diagram showing a specific configuration of a part of FIG.

FIG. 5 is a diagram showing a specific configuration of another part in FIG. 3;

6 is a flowchart showing a flow pulse output process performed by a μCOM CPU of the flow measurement unit in FIG. 3;

FIG. 7 is a timing chart illustrating a relationship between a flow rate pulse output by the process of FIG. 6 and a sampling interval.

[Explanation of symbols]

15 Display Means (Display) 20 Security Logic Means (Security Logic Unit) 14a-1 Passing Volume Calculation Means (CPU) 14a-2 1 / N Calculation Means (CPU) 14a-3 Accumulation Means (CPU) 14a-4 Accumulation Count Counting means (CPU) 14a-5 Subtraction means (CPU) 14a-6 Timing determining means (CP
U) 14a-7 Pulse generating means (CPU) 14a-8 Passing volume integrating means (CPU) 14c-1 Time storing means (RAM) 14c-2 Timer means (RAM)

Claims (4)

[Claims] 1. A passing volume is calculated intermittently at a fixed period, and every time a passing volume is calculated, 1 / N of the calculated passing volume is calculated.
A value is calculated, the calculated 1 / N value is sequentially integrated with the previous integrated value, and each time the integrated value becomes equal to or more than の of the unit passing volume, the number of times of integration is calculated, and the unit passing is calculated from the integrated value. 1 / of the volume
The subtraction of the value of 2 is repeated until the 1 / N value is integrated N times. The timing of inverting the output is determined by multiplying the number of integrations by 1 / N of the predetermined period. And generating a flow pulse corresponding to a unit passage volume of the gas having a cycle corresponding to the passage volume. 2. A passing volume calculating means for intermittently calculating a passing volume at a constant period, and a 1 / N value of said passing volume is calculated every time a passing volume is calculated by said passing volume integrating means. N calculating means; integrating means for sequentially integrating the 1 / N value; integrating until the integrated value by the integrating means becomes equal to or more than の of the unit passage volume until the 1 / N value is integrated N times. Means for counting the number of times of repeating the counting of the number of times, and until the 1 / N value is integrated N times, every time the value of the integrated value becomes one half of the unit volume of passage, the unit value of the unit volume of passage is calculated from the integrated value. Subtracting means for repeating the subtraction of the value of / 2, and multiplying the integration number by 1 / N of the predetermined period, and determining a timing for inverting an output until the passing volume calculating means next calculates a passing volume. Timing determining means for performing And a pulse generating means for inverting the output at a timing determined by the power determining means and generating a flow pulse corresponding to a unit passing volume of the gas having a cycle corresponding to the passing volume. 3. The time determining means: a time storing means for storing a time obtained by multiplying the integration number by 1 / N of the predetermined period; and sequentially reading and counting the time stored in the time storing means. Timer means, and the timer means measures the read time,
3. The flow rate pulse generator according to claim 2, wherein the passing volume calculating means determines the timing of inverting the output until the passing volume is calculated next. 4. The flow rate pulse generator according to claim 2, wherein a flow volume is calculated by the flow volume calculation means of the flow rate pulse generation apparatus; An electronic gas meter, comprising: a display unit for displaying a passing volume obtained; and a security logic unit for detecting a gas flow abnormality by a flow pulse generated by the flow pulse generator.