JPH0534080Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention A-1. Field of Industrial Use This invention relates to a device that transmits a signal from a sensor such as an industrial measuring instrument or a water meter to a receiver.

A-2 Prior art and its problems In the well-known data transmission device disclosed in Japanese Utility Model Application Publication No. 58-164096, an electronic meter, which is a sensor, and a receiver on the reading side are connected by an electric wire.

Therefore, there was a problem that electrical noise entered the sensor from this electric wire, which was a signal line, and destroyed data such as set values and integrated values of the electronic circuit, or caused malfunction. Furthermore, the format of the signal transmitted from the sensor is fixed, and there is a problem in dealing with receivers of different formats.

B. Structure of the invention B-1 Means for solving the problem In order to solve the above problems, the device of this invention includes a support member 1a for the light emitting diode 3 in the case 1 of an electronic water meter, and a supporting member 1a for the light emitting diode 3. The plug 1b attached to the lower end of the optical fiber cable 5 is connected to the lower end of the optical fiber cable 5 to form an integral unit, and this is detachably attached so that the lower end of the optical fiber 4 faces the diode 3. The upper end is connected to a housing case 7 for an optical-to-electrical converter installed at a distance from the water meter case 1, and the electric signal from the case 7 is transmitted to a receiver via an electric cable 11. The present invention is characterized in that a signal from a sensor such as an electronic water meter is transmitted to a receiver.

RO-2 Example In Fig. 1, 1 is the case of an electronic water meter, 2 is the window glass, and 3 is a light emitting diode, which is a format that determines the amount of water used and is stored in the electronic circuit of the water meter. It is sent as an optical pulse code signal. Reference numeral 4 denotes an optical fiber, whose lower end faces the light emitting diode 3 and is removably attached to the case 1. Reference numeral 5 denotes an optical fiber cable having an optical fiber 4, the upper end of which is connected to the case 7 through an optical connector 6. 8 is a photodiode facing the upper end of the optical fiber 4; 9 is an electronic circuit;
10 is a battery, 11 is an electronic cable, and the end of the core wire of this electric cable 11 is soldered to the electronic circuit board 9a. Further, the photodiode 8, electronic circuit 9, and battery 10 are mounted on an electronic circuit board 9a and fixed with a filler filled in the case.

As will be described later, the electronic circuit 9 includes a low power consumption amplifier circuit for amplifying the output of the photodiode 8, and a microcomputer (hereinafter referred to as microcomputer) for converting the format of the output signal of this amplifier circuit.
and has.

Figure 2 shows an electronic circuit, 8 is a photodiode, R1 to R11 are resistors, C1 to C5 are capacitors, Q1 to Q3 are transistors, IC2 is a buffer, X1 is a crystal oscillator, T1 and T2 are electronic cables 11. These terminals are connected as shown in the figure.

When a light pulse is input to the photodiode 8, a current flows through the resistor R1, and the waveform shown in FIG. 3a appears at point A. This voltage is applied to the gate of the voltage effect transistor Q1 through the capacitor C1, and its drain current increases, so that the voltage at point B becomes the waveform shown in FIG. 3b and is amplified by one stage. The voltage at point B becomes the waveform shown in FIG. 3B and is amplified by one stage. The voltage at point B is applied to transistor Q2 through capacitor C4.
, its collector current increases and C
The waveform at the point will be as shown in Figure 3C, and will be at a level that can be detected by a CMOS digital circuit. This signal is waveform-shaped by buffer IC2 and input to input SI of low current consumption CMOS one-chip microcomputer IC1. This microcomputer converts the input serial data into another predetermined format and outputs it serially from the output terminal D0.

The output voltage signal is applied to the gate of the enhancement type field effect transistor Q3, and its drain is connected as an output terminal to an external receiver 13 together with a terminal T2 via an electronic cable 11. Terminal T
1 is connected to the input terminal D1 of the microcomputer IC1 through the resistor R11, and by operating the switch S of the receiver 13, the terminal T1 is set to high level (3V or more).
When this happens, the microcomputer IC1 detects this, uses it as a start signal, operates according to a predetermined program, and the microcomputer outputs a signal. Transistor Q3 operates as an output buffer.

The current consumption in the example is when the microcontroller sends data.
It was 4μA, and 2μA in parts other than the microcontroller.

The conditions at this time are that the optical pulse width t1 is 2.5 μSec, the optical pulse period is 33 mSec, and the voltage of the battery 7 is 3V. Therefore, even if data is constantly transmitted, it can be operated for more than 10 years with a 1000mAH lithium battery.
In the above embodiment, the battery is built in the case 8, but the battery 14 built in the receiver 13 may be used to supply power to the transistors Q1 to Q3, the microcomputer, etc.

Effects of the invention Since the sensor and receiver are optically coupled and electrically isolated, the sensor is no longer destroyed or malfunctions due to electrical noise entering from the signal line.

Also, it has become easier to use one type of sensor to support receivers of different formats. In particular, in this invention, one end of the photodiode or optical fiber on the transmitting side is removably attached to the water meter case using parts such as a mounting member, a cap, and a plug, making it easy to mount watertightly to the meter case. However, since the optical/electrical conversion device is provided apart from the sensor, the electronic circuit section can be provided in a good environment, which is practically effective.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a main part of an embodiment of this invention, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is a diagram showing signal waveforms. 1...Sensor (electronic water meter) case, 3...Light emitting diode, 4...Optical fiber, 5...Optical fiber cable, 8...Photodiode, Q1-Q2...Transistor constituting the amplifier, IC1 ...microcomputer,
IC2...Battery, 7...Battery, 11...Electronic cable, 13...Receiver.

Claims (1)

[Scope of utility model registration request] A support member 1a for the light emitting diode 3 and a plug 1b attached to the lower end of the optical fiber cable 5 are connected to the case 1 of the electronic water meter by a cap 1c to form an integral body. The lower end of the fiber optic cable 5 is detachably attached so as to face the diode 3, and the upper end of the optical fiber cable 5 is connected to a housing case 7 for an optical/electrical converter installed apart from the water meter case 1. 1. A device for transmitting a signal from a sensor such as an electronic water meter to a receiver, characterized in that an electric signal from a sensor such as an electronic water meter is transmitted to a receiver via an electric cable 11.