JP4686848B2 - Flow measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flow rate measuring device that measures the flow rate of a gas or a liquid by ultrasonic waves.
[0002]
[Prior art]
Conventional ultrasonic velocimeters are generally as shown in FIG. This apparatus includes an ultrasonic sensor 2 installed in a measurement path 1 through which a fluid flows, a drive circuit 3 that drives the ultrasonic sensor 2, a control unit 4 that outputs a start signal to the drive circuit 3, and an ultrasonic propagation time. A timer 5 for measurement, a calculation unit 6 for receiving measurement data from the timer 5, an ultrasonic sensor 7 for receiving ultrasonic waves transmitted from the ultrasonic sensor 2, and an output of the ultrasonic sensor 7 according to the output of the gain control circuit 8 The variable gain amplifier 9 that amplifies at the amplification factor, the timing detection circuit 10 that compares the output of the variable gain amplifier 9 with the reference voltage and stops the timer 5 when the magnitude relationship is inverted, and the output level of the variable gain amplifier 9 And a level detection circuit 11 that outputs to the gain control circuit 8.
[0003]
In the ultrasonic current meter, when the drive circuit 3 receiving the start signal from the control unit 4 performs pulse driving of the ultrasonic sensor 2 for a certain period of time, the timer 5 starts measuring time according to the signal from the control unit 4. An ultrasonic wave is transmitted from the pulse-driven ultrasonic sensor 2. The ultrasonic wave transmitted from the ultrasonic sensor 2 propagates through the fluid to be measured and is received by the ultrasonic sensor 6. The reception output of the ultrasonic sensor 7 is amplified by the gain set by the control unit 4 in the variable gain amplifier 9. The timing detection circuit 10 receiving the output of the variable gain amplifier 9 determines reception of the ultrasonic wave and stops the timer 5. Then, the control unit 4 obtains the flow velocity from the time information t obtained from the timer 5 by (Equation 1) (the measurement time obtained from the timer 5 is t, the effective distance in the flow direction between the ultrasonic sensors is L, the sound velocity is c, The flow velocity of the fluid to be measured is v).
[0004]
v = (L / t) -c (Formula 1)
The timing detection circuit 10 compares the reference voltage and the received signal by a comparator.
[0005]
The received signal has a gently rising waveform, and the level of the received signal varies depending on the temperature characteristics of the ultrasonic sensor and the flow velocity. If the reference voltage and the level of the received signal are not appropriate, the operation of the timing detection circuit 10 is not stable and the measurement accuracy is deteriorated. Therefore, the level detection circuit 11 receiving the output of the variable gain amplifier 9 monitors the peak level of the input signal, and outputs to the gain control unit 8 when the peak value is small or large. The gain control unit 8 sets the amplification factor of the variable gain amplifier 9 so as to correspond to the signal from the level detection circuit 11 so that the output of the variable gain amplifier 9 becomes substantially constant. Then, the next received signal is amplified to a target signal level by the variable gain amplifier 9 and given to the timing detection circuit 10. Thus, by making the peak of the signal applied to the timing detection circuit 10 substantially constant, the timing for determining the reception time is stabilized.
[0006]
As another measurement method, the determination result of the timing detection circuit 10 may be returned to the drive circuit 3 after being delayed by a delay circuit instead of the timer 5 and then transmitted again. There is also a method of measuring the time by performing such a repetitive operation a predetermined number of times and obtaining the flow velocity by the calculation of (Equation 2) based on the measurement time (the delay time of the delay circuit is Td, and the number of repetitions is n The measurement time is ts, the effective distance in the flow direction between the ultrasonic sensors is L, the speed of sound is c, and the flow velocity of the fluid to be measured is v).
[0007]
v = L / (ts / n−Td) −c (Expression 2)
According to this method, it is possible to measure with higher accuracy than the method of (Equation 1).
[0008]
In addition, there is a method in which the ultrasonic sensor 2 and the ultrasonic sensor 7 are switched, the propagation times of the fluid under measurement from upstream to downstream and from downstream to upstream are measured, and the velocity v is obtained from (Equation 3) (upstream). Measurement downstream time T1, measurement from downstream to upstream time T2).
[0009]
v = L / 2 ((1 / t1)-(1 / t2)) (Formula 3)
According to this method, the flow rate can be measured without being affected by the change in the sound speed, and thus it is widely used for measuring the flow velocity, the flow rate, the distance, and the like.
[0010]
[Problems to be solved by the invention]
However, in conventional ultrasonic flowmeters, it is difficult from the viewpoint of power saving to keep the power supply in the drive circuit and variable gain amplifier at all times, and the timing to turn on and off the power is adjusted according to the characteristics of the measurement system. Otherwise, there is a problem that measurement accuracy is affected because measurement is started when it is not stable.
[0011]
[Means for Solving the Problems]
In order to solve the above-described conventional problems, the timer means of the present invention issues a signal for turning on the power to the power supply control means before sending the measurement start signal, and starts energization before the operation of the control means.
[0012]
As a result, the power supply operation is stopped by stopping the power supply at times other than measurement and energizing before the operation.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
First The invention includes a pair of transducers arranged in a flow path through which a fluid to be measured flows and transmits and receives ultrasonic waves; One of a pair of transducers Driving means for driving, control means for outputting a measurement start signal for operating the driving means, and the other vibrator of A flow rate calculation means for calculating the flow velocity of the fluid to be measured between the pair of vibrators by receiving an output, and a control means , Flow rate calculation means , And at least one of the drive means Power supply of Power supply control means for controlling on / off and timer means for managing measurement time intervals Voltage detection means for detecting the power supply voltage supplied to perform the measurement, The timer means , Before the control means sends the measurement start signal to the power supply control means Adjust the time to send the signal to the power supply control means according to the voltage detection means signal It is a flow rate measuring device that sends a signal to turn on the power.
[0014]
And power supply operation is stopped by stopping the power supply except during measurement and energizing before operation. It is possible The power input timing can be set to an optimum state by changing the stable time until the measurement start signal according to the power supply voltage.
[0015]
Second The invention Especially in the first invention, By enabling the power control means to operate from an external signal, the power supply of the measurement system is controlled by the external signal to enable optimum power control.
[0016]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
[0017]
Example 1
FIG. 1 illustrates the present invention. Example 1 It is a block diagram of an ultrasonic flowmeter. FIG. 2 is a diagram showing the operation timing of the transmission wave and reception wave of the ultrasonic signal. 1, the ultrasonic flowmeter of the present invention includes a flow path 1 through which a fluid to be measured flows, a first vibrator 12 and a second vibrator 13 that transmit and receive ultrasonic waves disposed in the flow path 1. , A driving means 14 for driving the first vibrator 12, a control means 15 for outputting a measurement start signal for operating the driving means 14, and an output of the second vibrator 13 in the flow path 1 A flow rate calculation means 16 for calculating the flow velocity of the fluid to be measured by calculation, a power supply control means 17 for controlling power on / off from the control means 15 to the flow rate calculation means 16, and a timer means 18 for managing the measurement time interval. Is.
[0018]
The flow rate calculation means 16 receives the reception signal of the second vibrator 13 and determines the reception timing, and the output of the timing detection means 19 is delayed by a predetermined delay time as a trigger signal for the drive means 14. A delay means 20 for outputting, a repeat means 21 for measuring the number of operations of transmitting / receiving ultrasonic waves and repeating the transmission / reception of ultrasonic waves again after the delay time by the delay means 20 and stopping the operation at a predetermined number of times, and at least the drive means 14 The time measuring means 22 for measuring the propagation time of the ultrasonic wave from the start of driving the first vibrator 12 to the stop of the operation of the repetitive means 21, and the flow velocity between the pair of vibrators is calculated from the value of the time measuring means 22 The calculation means 23 is used to obtain the flow rate.
[0019]
Further, a switching means 24 is provided between the driving means 14 and the first vibrator 12, and between the second vibrator 13 and the timing detection means 19, so that transmission / reception of ultrasonic waves is performed between the first vibrator 12 and the second vibration. You may make it carry out alternately between the child 13. FIG. In this way, when the transmission / reception is alternately performed by the switching means 24, the respective propagation times from the upstream to the downstream and from the downstream to the upstream of the fluid to be measured, which are also shown in the conventional example, are measured. And the flow rate can be determined from the flow velocity. This method is widely used because the flow rate can be measured without being affected by the change in the sound speed.
[0020]
The timer means 18 operates so as to send a power-on signal to the power control means 17 before the control means 15 sends a measurement start signal.
[0021]
This operation will be described below. Originally, the timer means 18 performs the operation of managing the measurement cycle T shown in FIG. 2 by periodically sending a signal to the power supply control means 17. This means that the control means 15 transmits an ultrasonic signal from the first vibrator 12 via the drive means 14 at a fixed time. The computing means 23 obtains the flow rate from the received signal and calculates the flow rate based on the time interval of the timer means 18.
[0022]
Usually, a power source 25 is connected to the power source control means 17 upstream thereof. When the power control means 17 is energized by the timer means 16, power is supplied to the control means 15 and the flow rate calculation means 16. The control means 15 sends a measurement start signal to the drive means 14 after the power is supplied, and the measurement operation is started.
[0023]
Here, if the measurement start signal is sent out immediately after the power is supplied, the operation of the drive means 14 and the flow rate calculation means 16 may not be normal yet. For this reason, the timer means 18 sends a signal for turning on the power before the control means 15 sends the measurement start signal to the power supply control means 17. As a specific example, the timer means 18 may be operated at the time interval T in order to manage the period T in FIG. 2, but in order to stabilize the measurement system, the time T 'is more than the time t0 as shown in FIG. Only before this, a signal is sent to the power supply control means 17 to supply power before the operation to the measurement system. Therefore, the cycle is not T but (T + T ′).
[0024]
By turning the power on and off in this operation, power supply is stopped except during measurement, and power is saved by energizing before operation. Since an unstable state can be avoided and the measurement start signal can be sent after the operation is stabilized, accurate flow measurement can be performed.
[0025]
(Example 2)
next Example 2 The flow rate measuring device will be described. FIG. 3 is a block diagram showing the configuration of the control means 15 of this embodiment. The difference from the first embodiment is that the main control means 26 for sending a measurement start signal to the drive means 14 inside the control means 15 and the second timer means for checking the time after the start of energization from the power supply control means 17. 27, and when the second timer means 27 reaches a predetermined time, a signal is sent to the main control means 26, and the main control means 26 receives this and sends a measurement start signal to the drive means 14. It is.
[0026]
The operation will be described below. The timer means 18 performs an operation of managing the measurement cycle T by periodically sending a signal to the power supply control means 17. When the power control means 17 is energized by the timer means 16, power is supplied to the control means 15 and the flow rate calculation means 16. The control means 15 sends a measurement start signal to the drive means 14 after the power is supplied, and the measurement operation is started.
[0027]
Here, if the measurement start signal is sent out immediately after the power is supplied, the operation of the drive means 14 and the flow rate calculation means 16 may not be normal yet. For this reason, the second timer means 27 in the control means 15 starts the time measuring operation as shown in FIG. 4B when the power supply control means starts supplying power at the time t1 in FIG. When the time T1 until the measurement system is stabilized after being energized is obtained in advance and set in the second timer means 27, an elapsed signal of the time T1 is sent to the main control means 26 at time t2. The main control means 26 receives this signal and sends a measurement start signal to the driving means 14. Then, a transmission signal as shown in FIG. 4C is output from the first vibrator via the driving means 14.
[0028]
As described above, by starting the power supply from the power supply control means 17 and sending a measurement start signal after a predetermined period of time has elapsed, an accurate flow rate can be obtained by starting the measurement after the measurement system operation is reliably stabilized. Measurement can be performed.
[0029]
(Example 3)
continue Example 3 The flow rate measuring device will be described. FIG. 5 is a block diagram showing the configuration of the control means 15 of this embodiment. The difference from the first embodiment is that a stability confirmation means 28 for confirming the stability of the operation of the drive means 14 and the flow rate calculation means 16 which are measurement systems is provided inside the control means 15.
[0030]
The operation will be described below. As shown in FIG. 2, the timer means 18 performs an operation of managing the measurement cycle T by periodically sending a signal to the power supply control means 17. When the power control means 17 is energized by the timer means 16, power is supplied to the control means 15 and the flow rate calculation means 16. The control means 15 sends a measurement start signal to the drive means 14 after the power is supplied, and the measurement operation is started.
[0031]
Here, depending on the measurement system, there may be a variation in the stabilization time after the power is supplied. For example, if there is a large capacitance component, it will be slow, and a simple circuit will be ready immediately. Therefore, it is necessary to confirm whether the operation of each measurement system is stable.
[0032]
The stability confirmation means 28 monitors the stable operation of each measurement system after the power supply control means 17 starts to supply power at time t1 in FIG. When the stability of each measurement system is confirmed, the confirmation signal is turned on as shown in FIG. The main control means 26 receives this signal and sends a measurement start signal to the driving means 14. Then, a transmission signal as shown in FIG. 6C is output from the first vibrator via the driving means 14.
[0033]
Here, the operation of confirming the stability of the stability confirmation means 28 may monitor the voltage of each measurement system, or may be configured to separately communicate with each individual block for confirming the stability. Alternatively, the time from the start of energization of each block may be simply viewed.
[0034]
Thus, after the power supply from the power supply control means 17 is started, the stability confirmation means 28 confirms that the operation of each measurement system is stable, and then the measurement start signal is sent, thereby ensuring the stability of the measurement system. The flow rate can be measured with higher accuracy by starting the measurement after that.
[0035]
Example 4
Example 4 The flow rate measuring device will be described. FIG. 7 is a block diagram showing the configuration of the control means 15 of this embodiment. The difference from the first embodiment is that a clock signal generation means 29 for digital circuit and a clock signal verification means 30 for confirming that the operation of the clock signal generation means 29 is stable are provided in the control means 15. is there.
[0036]
The operation will be described below. As shown in FIG. 2, the timer means 18 performs an operation of managing the measurement cycle T by periodically sending a signal to the power supply control means 17. When the power control means 17 is energized by the timer means 16, power is supplied to the control means 15 and the flow rate calculation means 16. When the control means 15 has a digital circuit when power is supplied, the normal clock signal generation means 29 starts oscillation.
[0037]
However, the rise of this clock signal is not constant due to external factors such as temperature and voltage. For this reason, the time until the clock operates stably is not constant. Therefore, an accurate flow rate cannot be obtained unless measurement is started after confirming the stability of the clock. The clock signal verification means 30 monitors the oscillation operation of the clock signal generation means 29 after the power supply control means 17 starts to supply power at time t1 in FIG. Then, when the clock source oscillation grows as shown in FIG. 8 (b), it is verified and if it is confirmed that the oscillation is sufficiently stable, the oscillation stability confirmation signal is turned on at time t2 as shown in FIG. 8 (c). To do. The main control means 26 receives this signal and sends a measurement start signal to the driving means 14. Then, a transmission signal as shown in FIG. 8D is output from the first vibrator via the driving means 14.
[0038]
Thus, after starting the supply of power from the power supply control means 17, the clock signal verification means 30 confirms that the oscillation clock of the digital circuit clock signal generation means 29 is stable, and then sends a measurement start signal. Since the clock count in the measurement system can be performed after the digital circuit is stabilized, a highly accurate flow rate measurement can be performed.
[0039]
(Example 5)
Example 5 The flow rate measuring device will be described. FIG. 9 is a block diagram showing the configuration of this embodiment. The difference from the first embodiment is that a temperature detecting means 31 and a voltage detecting means 32 are provided.
[0040]
The control means 15, the drive means 14, and the flow rate calculation means 16 have different stabilization times after energization depending on the ambient temperature. Therefore, a temperature detection means 31 is provided, and a signal from the temperature detection means 31 is provided. In In response, the timer means 18 for sending a signal for starting energization adjusts the time for sending the signal to the power supply control means 17 in accordance with the signal from the temperature detecting means 31, and the control means 15 sends a measurement start signal after the energization. It makes it possible to keep it stable before.
[0041]
For example, it takes a long time for the measurement system to become stable at low temperatures, such as in winter, and on the other hand, if it is installed in the summer or where direct sunlight shines, the temperature will be stable for a short time or already stable. It may be.
[0042]
In this way, it is possible to set the power input timing to an optimum state by changing the stabilization time until the measurement start signal after energization depending on the ambient temperature, and furthermore, it is possible to reduce wasteful power energization time. .
[0043]
In addition, the measurement systems of the control unit 15, the drive unit 14, and the flow rate calculation unit 16 may have different stabilization times depending on the supply voltage. Accordingly, the voltage detecting means 32 for monitoring the voltage of the power supply 25 supplied to the measuring system is provided, and the timer means 18 for sending a signal for starting energization according to the signal from the voltage detecting means 32 is provided with the temperature detecting means. The time for sending the signal to the power supply control means 17 is adjusted according to the signal 31 and it is possible to keep the control means 15 in a stable state before sending the measurement start signal after energization.
[0044]
For example, when a battery is used, the voltage is high at the beginning of operation, but the voltage gradually decreases as it is used. In the case of a high voltage, there is a high possibility that a large amount of current flows, and the amount of heat generated by each component of the measurement system is large. In this case, the stable state is reached quickly, and on the contrary, when the voltage is low, not much current flows and it takes time to reach the stable state. Considering these conditions, it is possible to set the power input timing to an optimal state by changing the stabilization time until the measurement start signal after energization according to the power supply voltage, and further reduce unnecessary power energization time. can do.
[0045]
Further, it is possible to perform a power saving operation by monitoring the voltage. In the figure, the temperature detecting means 31 and the voltage detecting means 32 are provided together, but if one of them is present, the operation can be sufficiently satisfied.
[0046]
(Example 6)
Example 6 The flow rate measuring device will be described. FIG. 10 is a block diagram showing the configuration of this embodiment. The difference from the first embodiment is that a first storage unit 33 and a second storage unit 34 are provided.
[0047]
The measurement systems of the control means 15, the drive means 14, and the flow rate calculation means 16 are not stable at the initial stage of operation, but gradually become stable as time passes after the start of energization. The stabilization time after energization may vary depending on the supply voltage. Therefore, the operation time until the measurement system is stabilized after energization is obtained in advance through experiments or the like and stored in the first storage means 33. If there is a variation between objects, the value obtained by inspection is stored. In the case of actual operation, the timer means 18 adjusts the time for sending a signal to the power supply control means 17 based on the operation time stored in the first storage means 33 and stabilizes the operation of the measurement system. Send measurement start signal.
[0048]
Accordingly, since the operation is based on information unique to the measurement system, a stable state can be easily adjusted, and variations in the flow rate measuring device can be reduced.
[0049]
For the measurement system stability, the optimum value may vary depending on the operation time when the stability is saturated, the clock stabilization time, the ambient temperature and the power supply voltage supplied.
[0050]
In order to improve the accuracy of the low flow rate, it is necessary to provide a measurement system that sufficiently incorporates such change factors. Therefore, the optimum stabilization time based on a combination of at least two or more of the operation time after power-on, the clock stabilization time, the ambient temperature, and the power supply voltage to be supplied until the measurement system is substantially stabilized is determined in advance. Is stored in the storage means 34.
[0051]
Further, when there is variation between objects in the measurement system, the value obtained by inspection is stored. In the case of actual operation, the timer means 18 adjusts the time for sending a signal to the power supply control means 17 based on the operation time stored in the second storage means 34 and stabilizes the operation of the measurement system. Send measurement start signal.
[0052]
This makes it possible to easily adjust the stable state because the initial operation takes into account the information specific to the measurement system and the surrounding state, and the variation in the flow rate measuring device can be reduced.
[0053]
The first storage means 33 is in a state that allows rewriting. For example, rewriting is performed from a microcomputer or by inputting a signal from the outside. It is also possible to replace the semiconductor itself in the semiconductor storage means. is there .
[0054]
As a result, when the optimum operating point of the initial stable time is deviated depending on the location and time of installation of the flow measuring device, the contents can be corrected. In addition, when an aging change or the like occurs, it can be similarly rewritten and dealt with. And it becomes possible to maintain a stable state for a long time.
[0055]
The second storage means 34 has a state that allows rewriting. As a result, when the optimum operating point for the initial stability of the measurement system is deviated depending on the location and time of installation of the flow rate measuring device, the contents are corrected. Even when the battery voltage ages or the aging of each constituent element occurs, it can be similarly rewritten and dealt with. This makes it possible to maintain a stable state for a long time.
[0056]
The first storage means 33 performs rewriting according to conditions during the measurement operation. For example, when the low flow rate state continues for a long time, the initial stability from the control unit 15 to the flow rate calculation unit 16 is further increased during the time period when the actual measurement operation is finished from the control unit 15 or the like in order to further increase the accuracy. Rewrite the conditions as follows. On the contrary, when the flow rate is large and the operation of the delay means can be sufficiently ignored as an error, the stability of the measurement system can be lowered to a certain level or less. As described above, it is possible to easily realize the optimum state as the measurement system by changing the initial operation of the measurement system according to the measurement state. And these will create the optimal power usage.
[0057]
The second storage means 34 performs rewriting according to conditions during the measurement operation. For example, this is a case where the temperature fluctuates rapidly depending on the installation location. In such a case, in order to maintain the accuracy, the condition is rewritten from the control unit 15 or the like so as to maintain the stability of the flow rate calculation unit 16 from the control unit 15 or the like in the time zone when the actual measurement operation is finished. In this way, it is possible to easily realize the optimum state by changing the initial operation of the measurement system according to the measurement state. In addition, it is possible to operate for a long time by considering the correlation with the power supply voltage.
[0058]
In the figure, the first storage means 33 and the second storage means 34 are combined. However, if there is one, the operation can be sufficiently satisfied.
[0059]
In the above description, the thermal balance in the measurement system from the control unit 15 to the flow rate calculation unit 16 has been described. However, the stability of the measurement system is not limited to heat, but the initial unstable state by operating for a fixed time in the same manner. The same effect can be obtained by avoiding.
[0060]
(Example 7)
Example 7 The flow rate measuring device will be described. FIG. 11 is a block diagram showing the configuration of this embodiment. The difference from the first embodiment is that an external connection means 35 is provided.
[0061]
The power supply control means 17 normally operates at a constant period based on the signal from the timer means 16, but there are cases where it is necessary to change this period or stop the measurement for a long period of time.
[0062]
Such a case may be dealt with by changing the contents of the storage means, but it is easier to operate directly from the outside and the application range is widened. An external connection means 35 capable of inputting a signal from an external device to the power control means 17 may be connected to control the power supply from the microcomputer 36 to the measurement system, for example.
[0063]
Thereby, when it is not used for a long period of time, it is possible to stop the fixed cycle operation and arbitrarily change the measurement cycle.
[0064]
Furthermore, the power supply of the measurement system can be controlled by an external signal, so that more optimal power control can be performed. When the power source is a battery or the like, the battery life (operation life) can be extended.
[0065]
【The invention's effect】
As is apparent from the above description, the flow measurement device of the present invention provides the following effects.
[0066]
(1) Since the timer means sends a signal to turn on the power before the control means sends the measurement start signal to the power supply control means, the power supply is stopped except during measurement, and power is turned on before operation to save power. In addition to performing the operation, supply power to the measurement system in advance to avoid an unstable state at the beginning of the operation and send a measurement start signal after the operation is stable so that accurate flow measurement is performed. Is possible.
[0067]
(2) After starting the power supply from the power supply control means, sending a measurement start signal after the elapse of a predetermined time, so that accurate measurement of the flow rate is achieved by starting the measurement after the measurement system operation is reliably stabilized Can be performed.
[0068]
(3) After starting the supply of power from the power supply control means, after confirming that the operation of each measurement system is stable by the stability confirmation means, and sending the measurement start signal, the stability of the measurement system is ensured. By starting the measurement, the flow rate can be measured with higher accuracy.
[0069]
(4) After starting the power supply from the power supply control means, after confirming that the oscillation clock of the clock signal generating means for the digital circuit is stable by the clock signal verification means, sending the measurement start signal, the digital circuit Since the clock count in the measurement system can be performed after stabilization, a highly accurate flow rate measurement can be performed.
[0070]
(5) By changing the stabilization time until the measurement start signal after energization depending on the ambient temperature, it is possible to set the power input timing to an optimum state, and furthermore, it is possible to reduce wasted power energization time. .
[0071]
(6) It is possible to set the power input timing to an optimum state by changing the stable time until the measurement start signal after energization according to the power supply voltage, and further, it is possible to reduce useless power energization time. .
[0072]
(7) The operation time until the measurement system is stabilized after being energized is stored in the first storage means, and based on this operation time, the timer means adjusts the time for sending a signal to the power supply control means, and the measurement system Since the measurement start signal is sent after the operation of the system is stabilized, it is possible to easily adjust the stable state because the operation is based on information unique to the measurement system, and the variation in the flow measurement device can be reduced. it can.
[0073]
(8) Second storage of an optimal stabilization time based on a combination of at least two or more of an operation time after power-on until the measurement system is substantially stabilized, a clock stabilization time, an ambient temperature, and a power supply voltage to be supplied The timer means adjusts the time for sending the signal to the power supply control means based on this operation time, and sends the measurement start signal after stabilizing the operation of the measurement system. Since an initial operation is performed in consideration of unique information and surrounding conditions, a stable state can be easily adjusted, and variations in the flow rate measuring device can be reduced.
[0074]
(9) The first storage means can be rewritten to correct the contents when the optimum operating point of the initial stable time is deviated depending on the location and time of installation of the flow rate measuring device. In addition, when an aging change or the like occurs, it can be similarly rewritten and dealt with. And it becomes possible to maintain a stable state for a long time.
[0075]
(10) Since the second storage means can be rewritten, the contents of the initial stable operating point of the measurement system can be corrected when the flow rate measuring device is installed at different locations and times. Further, even when a battery voltage aging or aging change of each component occurs, it can be rewritten and dealt with similarly. This makes it possible to maintain a stable state for a long time.
[0076]
(11) The first storage means can be easily rewritten according to the conditions during the measurement operation, thereby easily changing the initial operation of the measurement system according to the measurement state and establishing the optimum state for the entire measurement system. . And these will create the optimal power usage.
[0077]
(12) The second storage means can be easily rewritten according to the conditions during the measurement operation to change the initial operation of the measurement system according to the measurement state and establish an optimum state. In consideration of the correlation with the power supply voltage, it is possible to operate for a long time.
[0078]
(13) By controlling the power supply of the measurement system with an external signal, more optimal power control becomes possible, and when the power source is a battery or the like, the operating life can be extended.
[Brief description of the drawings]
FIG. 1 is an overall block diagram of a flow rate measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is a timing chart showing the operation of the oscillation wave, reception wave, and power control means of the flow rate measuring device.
FIG. 3 is a block diagram of control means in the flow rate measuring apparatus according to the second embodiment of the present invention.
FIG. 4 is a timing chart showing the operation of the power supply control means, the second control means, and the transmission wave of the flow rate measuring device.
FIG. 5 is a block diagram of control means in the flow rate measuring apparatus according to the third embodiment of the present invention.
FIG. 6 is a timing chart showing the operation of power control means, stability confirmation means, and transmission wave of the flow rate measuring device.
FIG. 7 is a block diagram of control means in a flow rate measuring apparatus according to Embodiment 4 of the present invention.
FIG. 8 is a timing chart showing the operation of power control means, block signal and transmission wave of the flow rate measuring device
FIG. 9 is an overall block diagram of a flow rate measuring device according to a fifth embodiment of the present invention.
FIG. 10 is an overall block diagram of a flow rate measuring device according to Embodiment 6 of the present invention.
FIG. 11 is an overall block diagram of a flow rate measuring device according to Embodiment 7 of the present invention.
FIG. 12 is an overall block diagram of a conventional ultrasonic velocimeter.
[Explanation of symbols]
1 channel
12 First vibrator
13 Second vibrator
14 Drive means
15 Control means
16 Flow rate calculation means
17 Power control means
18 Timer means
27 Second timer means
28 Stability confirmation means
29 Clock signal generating means
30 clock verification means
31 Temperature detection means
32 Voltage detection means
33 First storage means
34 Second storage means
35 External connection means

Claims (2)

A pair of transducers arranged in the flow path of the fluid to be measured and transmitting and receiving ultrasound;
Driving means for driving one of the pair of vibrators ;
Control means for outputting a measurement start signal for operating the driving means;
A flow rate calculation means for receiving the output of the other vibrator and calculating the flow velocity of the fluid under measurement between the pair of vibrators;
A power supply control means for controlling the turning on and off of at least one power supply of said control means, said flow rate calculation means, and said drive means,
Timer means for managing the measurement time interval ;
Voltage detecting means for detecting a power supply voltage supplied to perform measurement , and
Said timer means, before said control means sends the measured start signal to the power supply control unit, the signal to power by adjusting the time for sending a signal to the power control means in response to the signal of said voltage detecting means Flow rate measuring device that sends out. The flow rate measuring device according to claim 1 , wherein the power supply control means is operable from an external signal.

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