JPH0319492B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of generating data used in a flow meter.

In a general flow rate measuring device, an error, that is, an instrumental difference, occurs between the actual flow rate and the flow rate measured by the measuring device, making it impossible to accurately measure the flow rate.
That is, as shown in Figure 1, the most used flow rate 30
/min (the cross-sectional area of the conduit through which the fluid flows is constant, so the flow rate per unit time /min means the flow velocity), the instrumental error is zero, but at flow rates lower than that, there is a negative instrumental error, At high flow rates, positive instrumental error occurs. If you try to widen the range of use of flowmeters by correcting the instrumental error of the flowmeter itself, you will have to increase the processing precision and complicate the structure, resulting in disadvantages such as higher prices and reduced durability. arise. Therefore, the applicant did not modify the flowmeter itself,
The company previously filed an application for a flow rate measurement method that corrects the value measured by a flowmeter. An example of a device used in this method is as shown in FIG. 2, in which a counting circuit 3 counts the number of pulses from a clock pulse oscillator 2 for each pulse signal interval from a pulse oscillator 1 of the flowmeter; From this counted value, a flow rate corresponding to the number of clock pulses is selected in a storage circuit 4, and the resulting value is added in an adding circuit 5 and displayed on a display meter 6. Since the memory circuit 4 is inputted with data as shown in FIG. 3, which has been created in advance by taking into account instrumental differences, the memory circuit 4 can accurately calculate the number of clock pulses that have been counted. The flow rate is selected. However, in such a device, the data to be input into the memory circuit 4 is
As shown in FIG. 3, it was necessary to obtain a large number of numerical values by changing the flow rate in small increments, which required a great deal of effort.

For example, the technique for testing instrumental differences is disclosed in Japanese Patent Application Laid-Open No. 54-47677.
In this technique, in order to check the instrumental error of the flowmeter, when the counter of the flowmeter under test reaches a certain amount,
This stops the counting operation of the counting circuit of the reference flowmeter, and it is not possible to determine the instrumental error for a constant flow rate change.

Therefore, an object of the present invention is to create data used in flowmeters that can accurately determine the instrumental error for changes in flow rate over a certain width, thereby determining the correct flow rate value for each flowmeter. We are here to provide you with a method.

A method for creating data used in a flowmeter according to the present invention is to connect a reference flowmeter and a flowmeter to be created in series to a conduit, and create data based on flow rate data for a plurality of flow velocities from the reference flowmeter. The amount represented by one pulse of the flow rate pulse transmitted from the flow rate pulse transmitter of the flow meter is created in correspondence with the flow velocity.

Therefore, since the flow rates of the reference flowmeter and the flowmeter to be created are the same, it is possible to accurately know the amount per pulse of flow pulses corresponding to various flow rates, that is, flow velocities. A correction amount can be determined, and flow rate data corresponding to various flow velocities can be easily created.

When implementing the present invention, the number of clock pulses counted by the pulses from the reference flowmeter and the flowmeter to be created and the flow rate value stored in the reference flowmeter are calculated, and these values are calculated as the flow rate to be created. Preferably, the information is stored in the memory circuit of the meter.

Next, an example of the apparatus for carrying out the method of the present invention will be described in the fourth example.
The diagram will be explained. From tank 21 to pump 22
A reference flow meter 2 is connected to the conduit 23 through which liquid is sent by the
4 and newly created flowmeters 25a, 25b
are connected in series, and on-off valves 26 are installed at appropriate locations in the conduit.
is provided. The reference flowmeter 24 has a pulse transmitter 7 . The pulse oscillator 7 and the clock pulse oscillator 8 are connected to a counting circuit 9 of a first or reference flowmeter, which is connected to a first storage circuit 10. Accurate data of the flowmeter as shown in FIG. 3 prepared in advance is input into the memory circuit 10. Flowmeter 25a to be created
has a pulse transmitter 11, the pulse transmitter 1
1 and the clock pulse oscillator 8 are connected to a counting circuit 12 of the second flowmeter 25a to be created, the counting circuit 12 and the memory circuit 10 are connected to an arithmetic circuit 13, and the arithmetic circuit 13 is connected to a second memory 25a. The memory circuit 14 is connected directly to the counting circuit 12 . Exactly the same circuit is connected to the flowmeter 25b to be created, and many other flowmeters (not shown) are connected to the conduit 23.
may be connected in series.

In the above configuration, when the valve 26 is opened and the flow rate, that is, the flow rate flowing into the conduit 23 is gradually increased, a pulse is transmitted from the pulse transmitter 7 of the reference flowmeter 24, and the pulse transmitter 7 is transmitted in the first counting circuit 9. The clock pulses from the clock pulse oscillator 8 are counted at every pulse interval from The number of pulses is input to the arithmetic circuit 13. On the other hand, pulses are also transmitted from the pulse generator 11 of the flowmeter 25a to be created in accordance with the flow rate, and the clock pulses from the clock pulse generator 8 at each pulse interval are counted in the second counting circuit 12, and the counting pulses are The signal is input to the arithmetic circuit 13.
Let n 1 be the number of clock pulses from the clock pulse oscillator 8 counted between pulses from the pulse oscillator 7 of the reference flowmeter 24 at a certain flow rate, and let n ₁ be the flow rate value stored in the storage circuit 10 corresponding to the number of clock pulses n ₁ . a ₁ , and the number of clock pulses from the clock pulse oscillator 8 counted between the pulses from the pulse oscillator 11 of the flowmeter 25a to be created is
If n ₂ , the flowmeter 25a in the arithmetic circuit 13
The flow rate value represented by one pulse of the pulse generator 11 when the number of clock pulses n ₂ counted between the pulses from the pulse generator 11 is calculated, that is, a ₁ n ₂ /n ₁ , and is stored in the memory circuit _14. and a ₁ n ₂ /n ₁ are stored.

In this way, by changing the opening degree of the valve 26, the conduit 2
By changing the flow rate of 3, data is stored over the entire flow range as shown in FIG.
If the memory circuit 14 stored in this way is replaced with the memory circuit 4 of FIG. 2, and the pulse transmitter 11 of the flow meter 25a is replaced with the pulse transmitter 1 of FIG. A flow meter is obtained.

FIG. 6 shows another embodiment in which a clock pulse oscillator 81 is provided in each of the flow meters produced. The operation is such that the number of clock pulses from the clock pulse oscillator 8 counted between the pulses from the pulse oscillator 7 of the reference flowmeter 24 at a certain flow rate is n ₁ , and the number of clock pulses is n ₁ .
Let _a1 be the flow rate value stored in the memory circuit 10 corresponding to , and let n2 be the number of clock pulses from the clock pulse oscillator 8 counted between the pulses from the pulse generator 11 of the flowmeter 25a to be _created .
If the number of clock pulses from the clock pulse oscillator 81 is _n3 , then the flowmeter 2 is
When the number of clock pulses n ₂ n ₃ is counted between the pulses from the pulse generator 11 of 5a, the flow rate value represented by one pulse of the pulse generator 11, that is, a ₁ n ₂ /n ₁ is calculated and stored in the memory circuit 14. n ₃ and a ₁ n ₂ /n ₁ are stored in . In this way, by changing the opening degree of the valve 26,
By varying the flow rate in conduit 23, data is stored over the entire flow range, as shown in FIG. The memory circuit 14 stored in this manner is combined with the memory circuit 4 of FIG. 2 and the clock pulse oscillator 8.
1 with the clock pulse oscillator 2 of FIG. 2, and the pulse oscillator 11 of the flowmeter 25a with the pulse oscillator 1 of FIG. 2, one highly accurate flowmeter can be obtained. A clock pulse oscillator 81 is provided in each of the flowmeters to be created, the number of pulses of the oscillator 81 is stored in a memory circuit, and the oscillator is attached to the flowmeter shipped as a product, thereby reducing errors due to variations in the number of oscillations. disappears. The flowmeters to be manufactured are typically newly manufactured, but of course also include flowmeters whose instrumental error changes during use and must be corrected.

As explained above, the present invention calculates the number of clock pulses of a reference flowmeter, a flowmeter to be created, and a flow rate value stored in the reference flowmeter, and stores these values in the flowmeter to be created. Since it is automatically memorized in the circuit, the input work is easy, and once you have created one accurate reference flowmeter, you can mass-produce highly accurate flowmeters quickly and inexpensively. Can be done.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the instrumental error curve of a general flowmeter, Fig. 2 is a diagram showing an example of a flowmeter to which the present invention is applied, and Fig. 3 is a diagram showing the data to be input into the storage circuit of Fig. 2. FIG. 4 is a diagram showing an example of an apparatus for implementing the method of the present invention. FIG. 5 is a diagram showing an example of data input to the storage circuit of FIG. 4. FIG. 6 is a diagram showing an example of the data input to the storage circuit of FIG. Circuit diagram illustrating another device for carrying out the 7th
The figure is a diagram showing an example of data input to the circuit of FIG. 6. 3... Conduit, 4... Reference flow meter, 5a, 5b...
...Created flowmeter, 7,11...Pulse transmitter, 8...
...clock pulse oscillator, 14...memory circuit.

Claims (1)

[Claims] 1 Connect the reference flowmeter and the flowmeter to be created in series to a conduit, and calculate the flow rate pulses transmitted from the flow pulse generator of the flowmeter to be created based on the flow rate data for multiple flow rates from the reference flowmeter. A method for creating data used in a flowmeter, characterized in that the amount represented by one pulse is created in correspondence with the flow velocity.