JPS61288121A - Detection of liquid mixing ratio - Google Patents

Abstract

PURPOSE:To detect a mixing ratio with high accuracy by measuring the period of the flow rate pulses transmitted according to the flow rates of plural kinds of liquids to be mixed from said flow rate pulses. CONSTITUTION:An interruption signal from the 1st subtraction counter 11a is supplied to the 1st CPU13a and the period of the 1st flow rate pulse is measured when the 1st flow rate pulse is inputted to the counter 11a. The 1st frequency is calculated from the period and is outputted to the 1st I/O port 17a. The 1st flow rate pulse is inputted at the same instant to the 3rd subtraction counter 11c, from which the interruption signal is supplied to the 3rd CPU13c. The 2nd frequency F1 of the 2nd flow rate pulse is determined from the 2nd CPU13b when the 2nd flow rate pulse is inputted to the 2nd subtraction counter 11b. This frequency F1 is outputted to the 2nd I/O port 17b. An average frequency Fm is calculated from the 1st frequency and the frequency F1 is taken in from the port 17b. Said frequency is divided by the average frequency Fm to determine the frequency ratio. The frequency ratio thus determined is the ratio of an instantaneous flow rate and is therefore displayed as the mixing ratio on a mixing ratio display part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid mixing ratio detection method for detecting the mixing ratio when mixing a plurality of types of liquids, such as a main ingredient of a coating liquid, a hardening agent, etc.

(Prior art) Conventionally, it has been necessary to automatically mix different types of liquids, detect the mixing ratio, and control the mixing ratio to a constant level. A common method is to measure the number of flow rate pulses transmitted in accordance with the flow rate for a predetermined sampling period, calculate the instantaneous flow rate as a frequency from this measured value, and compare these frequencies to detect the mixing ratio. With this method, there is no problem when the number of flow pulses within a predetermined sampling time is large and the frequency becomes high, but if the amount of the mixed agent is minute compared to the main agent, such as a hardening agent in a coating liquid, and the amount of the mixed agent is small compared to the main agent, and the number of flow pulses within a predetermined sampling time is If the number of flow pulses is small and the frequency is low, the resolution of the flow pulses is also low, and depending on the sampling timing, the flow pulses may be emitted within a predetermined sampling time or within the next sampling time. As a result, the frequency varies greatly, and even if the mixing ratio is detected at this frequency, the value fluctuates widely, resulting in disadvantages such as the inability to perform highly accurate detection. As a method for eliminating this drawback, there is a method of detecting the period from each flow pulse and detecting each frequency from this period, as shown in FIG. 7A to 7B.

[Problem that the invention seeks to solve]

In this method, the period of the flow rate pulse changes according to the fluctuation of the instantaneous flow rate of each liquid, so when comparing the frequencies of each liquid, synchronization cannot be achieved, and as shown in Figure 7. I have no choice but to choose one of the frequencies fofl f2f
When 3f4f5 is calculated, the other previous frequency FOFI is called using this as the calculation timing, and the two frequencies are compared. In this case, if the period of one flow pulse is long, the mixing ratio is calculated several times for each flow pulse of the other, but the frequency of the long period flow pulse used for this calculation is the flow rate pulse at the time of calculation. Even though there are fluctuations in the cycle, the value is the same as the previous measurement.

Therefore, the calculated value of the mixture ratio becomes extremely inaccurate, resulting in drawbacks such as poor reliability.

(Means for Solving the Problems) The present invention aims to eliminate the above-mentioned drawbacks, and the present invention measures the period from the flow rate pulses transmitted according to the flow rates of multiple types of liquids to be mixed, and Each time a short flow pulse is transmitted, the period is added up, and when a flow pulse with a long period is transmitted, the average period of the added periods is calculated, and this average period is calculated as the period of the long period flow pulse. The system is configured to detect the mixing ratio of liquids.

Alternatively, each time the period is measured, it can be converted into a frequency, and the frequency is added each time a flow pulse with a short period is transmitted, and the frequency is added when a flow pulse with a long period is transmitted. It is also possible to determine the average frequency of the frequencies and detect the liquid mixing ratio based on this average frequency and the frequency obtained from the long period flow pulse.

(Function) In this liquid mixing ratio detection method, the instantaneous flow rate of the liquid is obtained as the period or frequency of the flow pulse. When comparing long and short cycles or high and low frequencies using pulses as calculation timing, the average value of the cycles or frequencies that have already been measured several times during that period is used as the cycle or frequency of the other flow pulse, so instantaneous The ratio of periods or frequencies representing the ratio of flow rates is extremely accurate, and the mixing ratio of liquids can be detected accurately.

(Example) Hereinafter, an example in which the instantaneous flow rate of each liquid is measured as a frequency, the frequencies are compared and calculated, and the mixing ratio of the liquids is detected will be described based on the drawings.

In FIGS. 1 to 4, 1 is a first flow ff1H+ that detects the flow rate of the first liquid flowing through the main line 6, and 7 is the flow rate of the second liquid flowing through the supply line 8 connected to the main line 6. This is a second flow meter that detects. The first flow meter 1 and the second flow meter 7 have the same structure and include a rotor 3 that rotates within a casing 2. The rotor 3 is configured to measure the discharge 1q (CC) when it rotates once, and a magnetic body 3a is embedded in the rotor 3. When this magnetic body 3a rotates,
The flow rate pulse is detected by four magnetic detection elements 4a on the top cover 4, and is configured to emit four flow rate pulses per rotation of the rotor.

The first flow meter 1 and the second flow meter 7 are configured to transmit a first flow pulse and a second flow pulse in accordance with the flow rates of the first liquid and the second liquid, respectively. The first flow rate pulse is a first subtraction counter 11 of the mixing ratio detection device 10.
It is configured to be input to the input terminal of a. This first
The output of the subtraction counter 11a is configured to send an interrupt signal to an interrupt terminal of a control timing section in the first CPU 13a. When this first CPU 13a receives an interrupt signal, it loads the first ROM1 as shown in FIG. 2a.
This first interrupt program, which is configured to execute the first interrupt program stored in RA 2a, 1) latches the period measurement counter 14 and transfers the data to the RA
Store in M15a.

2) Reset the period measurement counter 14a.

3) Start the period measurement counter 14a and start the oscillator 16.
Measure the number of time measurement pulses from.

4) Recall the data in the first RAM 15a.

5) Calculate the first frequency by calculating the reciprocal of the data, and output this first frequency to the first 10 ports 17a.

6) Multiply the first frequency by the conversion value K to the instantaneous flow rate/h, output the pupil value to the first display I10 port 19a, and display it on the first instantaneous flow rate display section 18a.

It is configured as follows.

Further, the second flow rate pulse is configured to be input to the input end of the second subtraction counter 11b of the mixture ratio detection device 10. The output of this second cotton reduction counter 11b is the second C
It is configured to send an interrupt signal to an interrupt terminal of a control timing section in the PU 13b. This second C
When the PU13b receives the interrupt signal, the second ROM12b
The second interrupt program is configured to execute a second interrupt program stored in the second interrupt program.

This second interrupt program has the same configuration as the first interrupt program, and is configured such that the data of the time measurement pulse obtained from the excavator 16 and the period measurement counter 14b is stored in the second RAM 15b. Further, the second frequency F1 is configured to be stored in the second I10 port 17b, and the calculated value for displaying the instantaneous flow rate in h/h is output to the second display I10 port 19b, and the instantaneous flow rate display section 18b is configured to be displayed.

Roughly speaking, the first flow rate pulse and the second flow rate pulse are input to the third subtraction counter 11C, and the output of the third subtraction counter 11C sends an interrupt signal to the interrupt terminal of the control timing section in the third CPU 13c. It is configured as follows. This third subtraction counter 11C has two counter sections 11o1 and 11o2, and is configured to transmit two types of signals. The third subtraction counter 11C is configured to execute a third interrupt program and a fourth interrupt program stored in the third RAM 12c, as shown in FIGS. 2 and 2C, in response to each pulse. There is. This third interrupt program is configured to be executed every time the first flow rate pulse is added to the counter section 11o1 of the third subtraction counter 11c and output from the third subtraction counter 11c, and includes: 1) the 1110th boat 17a; Take in the first frequency of and add it,
The added value is stored in the third RAM 15c.

2) Count the number of additions of the first frequency.

It is configured as follows.

Further, the fourth program is configured such that when the second flow rate pulse is applied to the counter section 11o2 of the third subtraction counter 11C, the third subtraction counter 11C outputs and is executed. Capture the second frequency F1.

2) Divide the addition frequency in the third RAM 15C by the number of additions to find the average frequency Fm.

3) Reset the number of additions.

4) Subtract the average frequency Fm by the second frequency F1 to obtain the frequency ratio.

5) This frequency ratio is output to the third display I10 boat 19c and displayed on the mixing ratio display section 20.

It is configured as follows.

In the above-mentioned mixing ratio detection device, as shown in FIG. 5A, when the first flow rate pulse is input to the first subtraction counter 11a,
An interrupt signal is sent from the first subtraction counter 11a to the first CPU1.
3a. The tenth PU 13a executes the first interrupt program, starts the period measurement counter 14a, and measures the period of the first flow rate pulse as shown in FIG.

On the other hand, as shown in FIG. 5H, a first frequency is calculated from this period and outputted to the 1110th boat 17a. Furthermore, the instantaneous flow rate is obtained in units of (e/h) by multiplying this first frequency by the conversion value K to the instantaneous flow rate/h, and this is displayed on the first instantaneous flow rate display section 18a. In this way, one frequency foflf2f3f4f5 is sequentially determined.

At the same time, the first flow rate pulse is input to the third subtraction counter 11C, and an interrupt signal is supplied from the third subtraction counter 11c to the third CPU 13c. The third CPU 13C executes the third interrupt program, and the third CPU 13C executes the third interrupt program.
The frequencies foflf2f3f4f5 are sequentially captured and added to count the number of captures. This is repeated until the second flow rate pulse is applied to the third subtraction counter 11c.

In that case, as shown in the fifth diagram, the second flow rate pulse is the second
When inputted to the subtraction counter 11b, the second CPU 13b executes the second interrupt program, and the period measurement counter 14b is activated to measure the period of the second flow rate pulse as shown in FIG. From this period, the second frequency F1 of the second flow rate pulse is determined as shown in FIG. 5, and this second frequency F1 is output to the second I10 port 17b. At the same time, the instantaneous flow rate changes to this second frequency F1.
By multiplying h by the conversion value K, the instantaneous flow rate is obtained as (Jl/h) and displayed on the second instantaneous flow rate display section 18b.

Further, the second flow rate pulse is input to the third subtraction counter 11C, and an interrupt signal is supplied to the third CPU 13c.

Therefore, the fourth interrupt program is executed, and the added first frequency is divided by the number of times of acquisition to calculate the average frequency Fm as shown in FIG. 5W. Further, a second frequency F1 is taken in from the second I10 port 17b, and this second frequency F1 is divided by the average frequency Fm at the calculation timing shown in the fifth graph to obtain the frequency ratio. Since this frequency ratio is also the ratio of instantaneous flow rates, this frequency ratio is displayed as a mixing ratio on the mixing ratio display section 20.

In the example, the instantaneous flow rate of each liquid is measured as a frequency, and the frequency is compared and calculated to detect the liquid mixing ratio. However, since the frequency is equal to the reciprocal of the period, the instantaneous flow rate of each liquid is calculated as the frequency. It is also possible to detect the liquid mixture ratio by measuring and performing a comparison calculation. In this case, it is only necessary to use the interrupt program shown in Figure 6 instead of the first interrupt program shown in Figure 2a, and the other interrupt programs can change the frequency by making the data to be processed periodic. The same can be used as in the case where the mixing ratio is determined as the reciprocal of the frequency.

This interrupt program: 1) Latch the period measurement counter 14 and store the data as a period in the first RAM 15a.

2) Reset the period measurement counter 14a.

3) Start the period measurement counter 14a and start the oscillator 16.
Measure the number of time measurement pulses from.

4) Recall the data in the first RAM 15a.

5) Output this cycle to the 1110th boat 17a.

6) Multiply the converted value to the instantaneous flow rate/h by ゛ in the first period, output the calculated value to the first display I10 port 19a, and display it on the first instantaneous flow rate display section 18a.

It is configured as follows.

[Effects of the Invention] As explained above, the present invention obtains the instantaneous flow rate of each liquid as its period or the frequency obtained from this, and calculates the period ratio or frequency ratio by using the long period flow pulse as the calculation timing. Since the liquid mixing ratio is calculated from the period or frequency and the average period or average frequency of the short period flow rate pulses in between, the period or frequency used for ratio calculation is not only extremely accurate, but also Even if the interval between calculations becomes longer and there is a flow rate fluctuation during that time, it is possible to extract the period or frequency that accurately corresponds to this and find the period ratio or frequency ratio, and it is possible to obtain an extremely accurate instantaneous flow rate ratio, that is, a mixing ratio. It has advantages such as being able to be detected.

[Brief explanation of drawings]

FIG. 1 is a block diagram explaining the present invention in detail, FIG. 2 is a flowchart showing an interrupt program according to the present invention, FIG. 3 is a vertical sectional view of main parts of a flowmeter according to the present invention,
The figure is a sectional view taken along the line A-A in Figure 3, Figure 5 is a signal waveform diagram showing the operating state of the present invention, and Figure 6 is an interrupt program forming the main part of another embodiment of the present invention. Flowchart 1~,
FIG. 7 is a signal waveform diagram showing the operating state of the conventional example. 1 First flow meter, 2 Casing, 3 Rotor, 3a Magnetic body, 4 Top lid,
4a Magnetic detection element, 5 6 Main line, 7 Second flow meter, 8 Supply line,
10 Mixing ratio detection device, 11a first numbing counter, 11b second subtraction counter, 1
1c third subtraction counter, 12a first ROM. 12b 2nd ROM, 12c 3rd ROM. 13a first CPU. 13b second CPU, 13c third CPU. 14a, 14b period measurement counter, 15a 1st RA
M, 15b 2nd RAM, 15c 3rd RAM. 16 oscillator, 17a 1110th port,
17b 2nd I10 boat, 18a 1st instantaneous flow rate display section,
18b Second instantaneous flow rate display section, 19a First display I10 port, 19b Second display I10 port, 19C Third display I10 port, 20 Mixing ratio display section, Fig. 6 Fig. 4 Fig. 3 a Fig. 5 (Force Pigeon 1 Taimi Monme Figure 7 (Power) 1'!'9 Te Minde

Claims (1)

[Claims] 1) The instantaneous flow rate is measured from the flow rate pulses transmitted according to the flow rates of multiple types of liquids to be mixed, and the instantaneous mixing ratio is detected by comparing the instantaneous flow rates. In the configured liquid mixture ratio detection method, the period of the flow rate pulse transmitted according to the flow rate of each liquid is measured, the period is added every time a flow pulse with a short period is transmitted, and the flow pulse with a long period is calculated. A method for detecting a liquid mixture ratio, characterized in that when the pulse is transmitted, an average period of the added periods is determined, and a liquid mixture ratio is detected based on this average period and the period of the long period flow rate pulse. 2) The period is converted into a frequency, and each time a flow pulse with a short period is transmitted, the frequency is added up, and when a flow pulse with a long period is transmitted, the average frequency of the added frequencies is calculated, and this average frequency and 2. The liquid mixture ratio detection method according to claim 1, wherein the liquid mixture ratio is detected based on a frequency obtained from a long period flow rate pulse.