JP2848046B2 - Detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detector built in a gas meter or a water meter for measuring the flow rate of gas or water flowing through the meter.

[0002]

2. Description of the Related Art A conventional detection device will be described with reference to FIGS. In FIG. 4, reference numeral 1 denotes a conversion element;
It is composed of magnetoresistive elements whose resistance values change depending on the strength of the magnetic fields 3, 4, and 5. 6 is a comparator, 7 is a feedback resistor, 8 is a power supply terminal, 9 is an output terminal, 10 is a common terminal, 1
1 is a detection element. When the strength of the magnetic field changes, the voltages applied to the positive and negative inputs of the comparator 6 change in opposite directions. When the polarity of the potential difference between the positive input and the negative input of the comparator 6 is inverted, the output of the comparator 6 changes. Since the positive feedback is applied by the feedback resistor 7, the detection element 1
1 has hysteresis. That is, when the intensity of the magnetic field applied to the conversion element 1 exceeds a certain level V1, the output terminal 9 goes high. In this case, the output terminal 9 changes to a low level at a level lower than a certain level V1 when the strength of the magnetic field decreases. The reason for providing such a hysteresis characteristic is to prevent the output generated at the output terminal 9 near the threshold level from fluttering.

FIG. 5 shows an example in which the conventional detecting element shown in FIG. 4 is applied to a membrane gas meter. In FIG. 5, reference numeral 12 denotes a disk which makes one rotation in conjunction with one reciprocation of the membrane of the membrane gas meter, 13 denotes a plurality of magnets arranged on the disk 12, and 11 denotes a detection element which is fixed and disposed near the disk 12. The change in the magnetic field is detected. 14 is an integrating means. Now, the operation of the gas meter having the above configuration will be described. When the gas flows, the film contracts and expands repeatedly according to the flow rate of the gas. Therefore, the disk 12 interlocked with the membrane rotates at a rotation speed corresponding to the flow rate. The detecting element 11 detects the rotation of the disk 12 by a change in magnetic field by a plurality of magnets arranged on the disk 12 and generates a pulse output according to the rotation speed of the disk 12. The pulse output is counted by the integrating means 14, the flow rate is converted, and the integrated output is displayed.

[0004]

However, in the above-mentioned conventional configuration, (1) power is always supplied to the detecting element 11, so that the detecting element consumes a large amount of power, so that a large battery is required. (2) If power is supplied intermittently for power saving, the hysteresis function inside the detection element does not work, so that there is a danger of chattering occurring near the threshold level and an integration error may occur. There was a problem that.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to maintain a hysteresis function even when power is supplied to a detecting element intermittently and to realize power saving.

[0006]

In order to achieve the above object, a detection device according to the present invention comprises a conversion element for converting a change in a physical quantity into a voltage change and whether or not the output from the conversion element exceeds a certain level. A detection element configured with a comparator for determining and having a power terminal for supplying power to the conversion element and the comparator, an output terminal for extracting an output of the comparator, a control terminal for controlling a determination level of the comparator, Power supply control means connected to a power supply terminal of the element for controlling supply power; sampling means connected to an output terminal of the detection element for sampling an output from the detection element in synchronization with a power supply control timing from the power supply control means And a gate connected to a control terminal of the detection element and synchronized with a power control timing from the power control means. And gate means for opening and closing the, in which a detection device is constituted by a latch means for outputting the latched said gate means output of said sampling means.

[0007]

According to the present invention, the hysteresis function can be maintained even if the power is supplied intermittently.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The same parts as those in the conventional example are denoted by the same reference numerals. In FIG. 1, reference numeral 12 denotes a disk that makes one rotation in association with one reciprocation of the membrane of the membrane gas meter, 13 denotes a plurality of magnets arranged on the outer periphery of the disk 12, and 11 denotes a detection element which is near the disk 12. At a fixed position to detect a change in the magnetic field. 16 is a power control means, 17 is a sampling means,
Reference numeral 18 denotes a latch means, 19 denotes a gate means, and 20 denotes a detection device constituted by means indicated by reference numerals of the detection elements 11, 16, 17, 18, and 19. The signal from the detection device 20 is integrated and displayed by the integrating means 14. Detection element 11
2 will be described with reference to FIG. In FIG. 2, 1
Is a conversion element, which is composed of a magnetoresistive element whose resistance value changes according to the strength of the magnetic field indicated by reference numerals 2, 3, 4, and 5. 6 is a comparator, 7 is a feedback resistor, 8 is a power supply terminal,
9 is an output terminal, 10 is a common terminal, 15 is a control terminal, 11
Is a detection element. The detecting element 11 is configured as a monolithic IC on the same silicon substrate. When the control terminal 15 is at a high level and when it is at a low level, the threshold level at which the output of the output terminal 9 changes according to the strength of the magnetic field. Therefore, by controlling the control terminal 15 from the outside, it is possible to provide a hysteresis characteristic.

Next, the operation of the detecting device 20 having the above configuration will be described with reference to FIG. FIG.
FIG. 4 is a timing chart for explaining the operation of FIG. In FIG. 3, a signal A is a signal that is output to the output terminal 9 of the detection element 11 when power is continuously applied to the power supply terminal 8 of the detection element 11. The signal B is an output of the power supply control means 16 and supplies power intermittently to the power supply terminal 8 of the detection element 11. The sampling means 17 samples the output signal from the detection means 11 at the timing of the signal C. The signal D sampled by the sampling means 17 is latched by the latch means 18 to become an output signal E. The gate means 19 opens at the timing of the output signal B of the power supply control means 16 and transmits the output signal E of the latch means 18 to the control terminal 15 of the detection element 11. Therefore, the control terminal 15 of the detecting element 11
Is applied with a signal F.

In this embodiment, a monolithic IC is considered as the detecting element 11. However, the magnetoresistive element 1 and the comparator 6 are composed of separate elements, and are configured like a so-called hybrid IC in which they are mounted on the same substrate. It does not matter.

In the present embodiment, a positive power supply is considered as the power supply terminal of the detecting element 11, but a negative power supply may be used.

[0012]

As described above, according to the detecting apparatus of the present invention, the output level of the detecting element at the previous sampling timing is controlled in accordance with the intermittent operation timing controlled by the power supply control means. Since the detection element is fed back to the terminal 15, the detection element has a hysteresis characteristic, so that both power saving and integration without malfunction due to chattering can be realized at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram of a detection device according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a detection element used in the apparatus.

FIG. 3 is a signal timing chart for explaining the operation of the detection device.

FIG. 4 is a circuit configuration diagram of a conventional detection element.

FIG. 5 is a block diagram when a conventional detection element is used in a gas meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conversion element 6 Comparator 8 Power supply terminal 9 Output terminal 10 Common terminal 11 Detection terminal 15 Control terminal 16 Power supply control means 17 Sampling means 18 Latch means 19 Gate means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-135728 (JP, A) JP-A-56-135122 (JP, A) JP-A-3-206917 (JP, A) JP-A-3-135 242512 (JP, A) JP-A-3-242513 (JP, A) JP-A-58-8121 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01F 15/075 G01F 3 /twenty two

Claims (1)

(57) [Claims] 1. A converter for converting a change in a physical quantity into a voltage change, and a comparator for determining whether an output from the converter has exceeded a certain level, and supplying power to the converter and the comparator. A detection element having a power terminal for controlling the output of the comparator, a control terminal for controlling a judgment level of the comparator, a power control means connected to a power terminal of the detection element for controlling supply power, A sampling means connected to an output terminal of the element and sampling an output from the detection element in synchronization with a power control timing from the power control means; and a power control from the power control means connected to a control terminal of the detection device Gate means for opening and closing the gate in synchronization with the timing; and latching the output of the sampling means. Detecting device constituted by a latch means for outputting the serial gate means.