JPS62142225A - Measuring instrument for flow rate - Google Patents

Abstract

PURPOSE:To reduce a consumption electric current and to measure flow rate strong in noise with high reliability by confirming both states when a read switch is on or off and then, first processing count of the flow rate. CONSTITUTION:In case the reed switch is on, the voltages of both ends of a capacitor 3 of the 1st series circuit are monitored with a signal processing circuit 8 with the timing when the pulse voltages are generated on both ends of resistance 4 of the 2nd series circuit by the electric discharge of the capacitor 3 of the 1st series circuit and further, in case the switch 1 is returned to off by an OR circuit 7, the voltages of both ends of the capacitor 3 of the 1st series circuit are similarly monitored with the circuit 8 with the timing when the pulse voltage is generated on output of a trailing edge detection circuit 6. Then, the count of the flow rate is first processed with the circuit 8 when the states of an and off are detected. As a result, the flow rate can be measured with the high reliability without a fear of the wrong count even if the pulse voltage by the noise is generated when the reed switch is on.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a fluid flow rate measuring device [? In particular, the present invention relates to a flow measuring device with low current consumption, high accuracy, and high reliability.

Conventional technology Conventional flow rate measuring devices designed to reduce current consumption include:
For example, there was one shown in Figure 3.

Reference numeral 1 denotes a reed switch, which is turned on every time a predetermined unit meter unit of fluid is measured in combination with a permanent magnet (not shown) provided in the rotating part of the mechanism section of the flow hV measuring device. Resistor 2 and capacitor 3 constitute a first series circuit, and capacitor 3
A second series circuit consisting of a reed switch 1 and a resistor 4 is connected in parallel. In order to reduce the current consumption, the resistor 2 is connected to a resistor 4 to the extent that it does not affect the current measurement.
A resistance value sufficiently larger than that is used. Reference numeral 9 denotes an RS latch which receives the voltage across the resistor 4 and the reset output from the signal processing circuit 10, and its output is input to the signal processing circuit 10. 10 is a signal processing circuit, RS latch 9
When the process is completed, the reset output is sent to RS.
Return to latch 9.

Next, one masterpiece of the apparatus shown in FIG. 3 will be explained with reference to the operation timing chart shown in FIG. a is the on/off state of the reed switch 1, b is the voltage across the capacitor 3, C is the voltage across the resistor 4, d is the output d of the RS latch 9, and e is the signal processing circuit 10. Indicates reset output.
At to, a capacitor 3 is charged via a resistor 2. When reed switch 1 is turned on at time t1, the discharging time constant of resistor 4 and capacitor 3 is made smaller than the charging time constant of resistor 2 and capacitor 3, so the electric charge charged in capacitor 3 is discharged through resistor 4, and the RS latch is activated. A pulse waveform shown in C is applied to the set input SK of RS latch 9, and the output d of the RS latch 9 changes from Hl to LO as shown in d.

Then, when the signal processing circuit 10 receives the large Lo input from the cigarette, it performs flow counting processing, and when the processing is completed at time t2, e
The reset output shown in d is output, and the output Q of the RS latch 9 returns from Lo to Hi as shown in d. Furthermore, time t3
When reed switch 1 turns off, capacitor 3 becomes resistor 2
It is charged again via , and returns to the state at the initial time to.

As described above, the device shown in FIG. 3 has the advantage that the current consumption of the circuit can be kept as low as possible by selecting the resistance value of the resistor 2 to be sufficiently large.

Problems to be Solved by the Invention However, since such conventional devices use latches, there is a risk of erroneous counting due to noise. For example, if there is noise as shown by the dotted line C at time t4 in FIG. 4, there is a risk that the latch will be reversed and erroneous counting will occur.

Such erroneous counts can be caused by devices that measure the instantaneous value of flow rate per unit time and shut off the line in the event of an abnormal flow rate. In the case of an integrated type that measures how much volume is consumed, this erroneous count accumulates, which could pose a serious problem in the case of a meter for calculating charges.

The present invention solves these conventional problems, and aims to provide a highly accurate and reliable flow rate measuring device that is resistant to noise while reducing current consumption.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the current measuring device of the present invention includes a series circuit of a resistor and a capacitor of fJ1, and a predetermined unit meter connected in parallel with the capacitor is a volume meter. a second series circuit of a reed switch and a resistor that is turned on each time the fluid is measured; and a falling edge detection circuit that is preceded by an impark that receives the voltage across the capacitor of the first series circuit. , an OR circuit whose inputs are the voltage across the resistor of the @2 series circuit and the output of the falling edge detection circuit, and the voltage across the capacitor of the first series circuit of 677 and the output of the OR circuit. It is composed of a signal processing circuit as an input.

Effect: With the above-described configuration, the present invention causes the fall and spring when the reed switch is turned on to occur at the timing when a pulse voltage is generated across the resistor of the second series circuit due to discharge of the capacitor of the first series circuit. The voltage across the capacitor in the first 1σ column circuit was monitored by the signal processing circuit, and when the reed switch was turned off again by the OR circuit, a pulse voltage was generated at the output of the falling edge detection circuit. The signal processing circuit also monitors the voltage across the capacitor in the first series circuit at the same timing, and only when the states of both are detected does the signal processing circuit perform the flow rate counting process. Even if a pulse voltage due to noise is generated across the resistor of the second series circuit while the reed switch is on, this is not counted. Therefore, the noise resistance is significantly improved, and there is no problem when used in an integral type flow rate measuring device for charge calculation. Furthermore, by setting the resistance of the first series circuit to a sufficiently large resistance value, the current consumption of the circuit can be kept as low as possible.

EXAMPLES Hereinafter, examples of the present invention will be explained with reference to FIGS. 1 and 2.

In Figure 451, 1 is a reed switch, which is a permanent magnet (not shown) installed in the rotating part of the flow measuring device mechanism.
In combination with this, it is turned on every time the fluid in the predetermined unit material td:body is measured. The resistor 2 and the capacitor 3 constitute a first one-segment series circuit, and a second series circuit including the reed switch 1 and the resistor 4 is connected in parallel to the capacitor 3. In order to reduce current consumption, a resistor f+f is used as the resistor 2, which is sufficiently larger than the resistor 4 without affecting flow measurement. The voltage across capacitor 3 is inverted using a 5-digit inverter. A falling edge detection circuit 6 detects the falling edge of the output of the inverter 5 and outputs a pulse voltage. 7 is an OR circuit which receives the voltage across the resistor 4 of the second series circuit and the output of the falling edge detection circuit 6 as inputs. Reference numeral 8 denotes a signal processing circuit which receives the output of the OR circuit 7 and the voltage across the capacitor 3 of the series circuit @1 and performs flow rate counting processing.

The operation of the above device will be explained with reference to the operation timing chart in FIG. a indicates the on/off state of the reed switch 10, b
represents the voltage across the capacitor 3, C represents the voltage across the resistor 40, d represents the output of the inverter 5, e represents the output of the falling edge detection circuit 6, and f represents the output of the OR circuit 7. At time to, capacitor 3 is being charged via resistor 2. When reed switch 1 is turned on at time t1, the discharge time constant of resistor 4 and capacitor 3 is changed to resistor 2 and capacitor 3.
Since the charging time constant is smaller than the charging time constant of , the load charged in the capacitor 3 is applied to the resistor 4 by 11 p, and a pulse pressure shown as C is generated across the resistor 4.

Next, when the reed switch 1 is turned off at time t2, the capacitor 3 is charged via the resistor 2, and the inverter 5 is charged with b
voltage is input, and at time t3, the output of inverter 5 is d
It changes from Hi to LO as shown in . Then, when the falling edge detection circuit 6 detects this falling edge from Hi to Lo, it outputs the pulse pressure indicated by θ, so the pulse voltages C and e are inputted to the OR circuit 7 and outputted. becomes like f. When the signal processing circuit 8 receives the pulse voltage at time t, the signal processing circuit 8 confirms that the reed switch 1 is on because the voltage across the capacitor 3 at b is Lo. , Subsequently, when a pulse voltage is received at time t3, the voltage across the capacitor b becomes Hi, so the reed switch 1
is off, and only when both are confirmed will the flowmeter count process. Therefore, for example,
Even if there is noise as shown by the dotted line C at time t4 in FIG. 2, n will not be counted incorrectly.

Effects of the Invention The flow measuring device of the present invention provides the following effects.

(1) Since the flow rate is counted only after checking both the state when the reed switch is turned on and the flow rate when the reed switch is turned off, there is no risk of miscounting due to noise, and the system is highly accurate and reliable. It is possible to measure flow rates with high accuracy.

(21) By setting the resistance of the first series circuit to a sufficiently large resistance value, the current consumption of the circuit can also be kept low.

[Brief explanation of drawings]

Fig. 1 is an electric circuit diagram of a flow rate measuring device showing an example of the present invention, Fig. 2 is a timing chart for explaining the same operation, Fig. 3 is an electric circuit diagram of a conventional flow rate measuring device, and Fig. 4 is a timing chart for explaining the same operation. 1...Reed switch, 2...Resistor, 3
... Capacitor, 4 ... Resistor, 5 ...
Inverter, 6... Falling edge detection circuit, 7. O
R circuit, 8...signal processing circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure Otsu Figure 2 ・t4t, 3 Figure 3 Foil Figure 4

Claims (1)

[Claims] a first series circuit of a resistor and a capacitor; a second series circuit of a reed switch and a resistor connected in parallel with the capacitor and turned on each time a predetermined unit volume of fluid is measured; and the first series circuit. a falling edge detection circuit in which an inverter is placed at the front stage, which inputs the voltage across the capacitor; and an OR circuit, which inputs the voltage across the resistor of the second series circuit and the output of the falling edge detection circuit. and a signal processing circuit whose inputs are the voltage across the capacitor of the first series circuit and the output of the OR circuit.