JPH06124396A - No power supply type measuring instrument - Google Patents

Abstract

PURPOSE:To provide the no power supply type measuring instrument which is greatly reduced in power consumption by simplifying the circuit constitution and performs continuous measuring operation sufficiently with a small-sized solar battery. CONSTITUTION:The measuring instrument consists of the solar battery 1, a power circuit 2 which accumulates the output voltage of the solar battery 1 and outputs a specific voltage, a diode 3 which lowers and supplies the output voltage of the power source circuit 2 to an electric power supply control circuit 4, an information measuring circuit 6 equipped with a sensor 5 which detects information on the amount, temperature, pressure, etc., of water, and an LED driving circuit 8 which drives an LED 7 with the output signal of the information measuring circuit 6. An operating voltage of 1.5-2V is applied from the electric power supply control circuit 4 to the information measuring circuit 6 for a period of 100 miliseconds at a period of 10 seconds to place the information measuring circuit 6 in operation and information detected by the sensor 5 is converted into a pulse signal to drive the LED 7 with pulses. A blinking light signal from the LED 7 is sent to the measuring use load of a center information monitor system through an optical fiber 9 to display measurement information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parasitic measuring device installed at a remote location, and more particularly to a passive measuring system for converting information measured at a remote location into an optical signal and transmitting it to a measuring load. It relates to the device.

[0002]

2. Description of the Related Art For example, in a petroleum plant, a terminal device (measuring device) equipped with a sensor for detecting information such as the water content, temperature, and pressure of crude oil is installed in a tank at a remote location where crude oil is stored. Information detected by this sensor,
For example, whether or not the crude oil in the tank is maintained in an appropriate state is sent via a transmission cable to a measurement load, which is a measuring instrument such as a moisture meter, thermometer, and pressure gauge in the central information monitoring system. I try to monitor it all the time.

In such a field-installed measuring device, it is often difficult to supply a power supply voltage from the outside for the purpose of increasing installation safety and explosion-proof safety. For this reason,
Generally, a solar cell is used as a power source of a measuring device installed on site.

[0004]

However, the above-mentioned field-installed measuring device has to continuously measure and transmit information to the measuring load regardless of day or night. On the other hand, there is a limit to the capacity of power that can be supplied by a solar cell, which makes continuous measurement at night difficult. Therefore, it is conceivable to use a large-capacity solar cell, but this causes the power supply circuit of the measuring device to become large, resulting in a significant cost increase, and the installation location of the large-capacity solar cell becomes a problem. There are drawbacks.

Therefore, an object of the present invention is to provide a passive system which simplifies the circuit structure, reduces the size and cost, and significantly reduces the current consumption, so that a small solar cell can sufficiently perform continuous measurement. It is to provide a measuring device.

[0006]

The above-mentioned object is achieved by the measuring system of the passive type according to the present invention. In summary, the present invention provides a solar cell, a power supply circuit for accumulating the output voltage of the solar cell and outputting it at a predetermined voltage, and a constant operating voltage supplied through a means for lowering the output voltage from the power supply circuit. A power supply control circuit, and an information detection means for detecting information on an object to be measured, the information measurement circuit operating by power supply from the power supply control circuit, and a drive for driving a light emitting element by an output signal from the information measurement circuit. A circuit and an optical transmission means for transmitting an optical signal output from the light emitting element to a measurement load, and the operating voltage is supplied from the power supply control circuit to the information measuring circuit for a very short period at a predetermined cycle. A pulse signal corresponding to the information of the object to be measured is output from the information measuring circuit to blink the light emitting element only during the time when the operating voltage is being supplied, and the blinking optical signal is transmitted to the optical transmission means. A measuring device of the passive type, characterized in that so as to transmit to the measuring load through.

[0007]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the basic configuration of an embodiment of a passive measuring apparatus according to the present invention. The measuring device of this embodiment is
The solar cell 1, a power supply circuit (secondary battery) 2 that accumulates the output voltage of the solar cell 1 and outputs it at a predetermined voltage, and lowers the output voltage of the power supply circuit 2 and supplies it to the power supply control circuit 4. Power supply voltage lowering means, in this embodiment, four diodes 3 connected in series, and a sensor 5 for detecting information such as water content, temperature, pressure, etc., and information measurement operated by power supply from the power supply control circuit 4 The circuit 6 and an output signal from the information measuring circuit 6 cause a light emitting element, L in this embodiment.
The LED drive circuit 8 drives an ED (light emitting diode) 7.

In the present embodiment, as shown in FIG. 2, the power supply control circuit 4 outputs 100 at a period of 10 seconds (SEC).
A voltage of 1.5 to 2 V (volt) is supplied to the information measuring circuit 6 only for a millisecond (mS) time, and the information measuring circuit 6 is operated for a period of 100 milliseconds in a cycle of 10 seconds. Information such as the water content, temperature, and pressure detected by the sensor 5 is converted into a pulse signal, and this pulse signal is supplied to the LED drive circuit 8 to pulse-drive the LED 7 to blink it. The blinking light signal from the LED 7 is transmitted through the optical fiber 9 to a measurement load, which is a measuring instrument such as a moisture meter, a thermometer, and a pressure gauge of the central information monitoring system.

In the load for measurement, for example, a microcomputer detects the frequency of the pulse signal from the blinking of light within a fixed time (100 milliseconds in this example), and based on the detected frequency, the corresponding water content, temperature, pressure, etc. The value of the measured information of is calculated and displayed.

As described above, when the information measuring circuit 6 is operated for a very short period of time at a short fixed period such as 10 seconds, and the pulse signal is generated to drive the LED 7 to blink, the sensor 5 and the information measuring circuit are driven. 6, LED7 and LED
Since the current consumed in the drive circuit 8 is very small, the solar cell 1 and the power supply circuit 2 having a relatively small power supply capacity are provided.
Even if is used, continuous measurement with no power supply is sufficiently possible, and the problem of interrupting measurement at night does not occur. Also,
Since the period is as short as 100 milliseconds but is as short as 10 seconds, the measurement data detected by the sensor 5 is transmitted substantially continuously and no problem occurs.

Next, the information measuring circuit 6 which consumes extremely little current and is suitable for use in the passive measuring apparatus according to the present invention will be described.

For example, as a sensor for detecting the concentration of a component in a liquid phase such as the amount of water in crude oil, a moisture (gas) sensor having a capacitance changing type electric characteristic or a resistance changing type electric sensor is used. Moisture (gas) sensors that have specific characteristics are often used. As shown in FIGS. 3 and 4, these sensors are, for example, a C-MOS type first Schmitt inverter 21, a resistor R1 inserted in a feedback circuit of the inverter 21, and an input of the first inverter 21. It is used as an oscillating frequency determining element of the CR oscillating circuit 20 including an electrostatic capacity element (capacitor) C1 connected to the side.

That is, in FIG. 3, a capacitance change type sensor Ch whose capacitance changes according to the change of the concentration of the object to be measured such as moisture is provided with the input side of the first inverter 21. The CR oscillation circuit 20 is configured by being inserted in series with the capacitive element C1, and the capacitance of the sensor Ch changes according to the change in the concentration of the measured object, whereby the CR oscillation circuit 20.
The oscillation frequency is changed correspondingly to generate a pulse signal corresponding to the concentration of the object to be measured.

Further, in FIG. 4, a resistance change type sensor Rh whose electric resistance value changes in response to a change in the concentration of an object to be measured such as moisture is inserted in the feedback circuit of the first inverter 21. The CR oscillation circuit 20 is configured by inserting a resistance element for determining the oscillation frequency in place of R1, and the electric resistance value of the sensor Rh changes in accordance with the change of the concentration of the object to be measured. The frequency is correspondingly changed to generate a pulse signal corresponding to the concentration of the object to be measured.

Further, as shown in FIG. 5, a sensor GS having an electric characteristic in which the capacitance component C and the electric resistance component R are changed according to the change in the concentration of an object to be measured such as water is used, and the same is used. The first, second and third three switches X of the configuration,
When used as a capacitance change type sensor with Y and Z, as shown in FIG. 3, this sensor GS is connected in series between the input side of the first inverter 21 and the capacitance element C1. Further, when it is used as a variable resistance type sensor, as shown in FIG. 4, this sensor GS is switched and connected so as to be inserted in the feedback circuit of the first inverter 21 in place of the resistor R1. There is also proposed a configuration that constitutes the CR oscillation circuit 20 shown in FIGS. 3 and 4.

The first, second and third switches X, Y,
Z has one movable contact XC, YC, ZC and two fixed contacts X0 and X1, Y0 and Y1, Z0 and Z1, respectively, and the first switch X has a movable contact XC whose resistance R2 is for removing DC voltage. Is connected to the connection point of the electrostatic capacitance element C1 and the first fixed contact X0 is not connected, and the second fixed contact X1 is connected to the input side of the first inverter 21. In addition, the movable contact YC of the second switch Y is connected to the other terminal of the sensor GS, and the first fixed contact Y0 is connected to the connection point between the resistor R2 for removing the DC voltage and the electrostatic capacitance element C1. , The second fixed contact Y1 is the third switch Z
Of the second fixed contact Z1. Furthermore, the third
The switch Z has a movable contact ZC of the first inverter 2
1 is connected to the output side, and the first fixed contact Z0 is connected to the resistor R1.
It is connected to the.

In the above structure, the three switches X,
When the movable contacts XC, YC, ZC of Y, Z are connected to the first fixed contacts X0, Y0, Z0 as shown in the figure, the resistor R1 is inserted in the feedback circuit of the first inverter 21. , The sensor GS is connected in series with the capacitive element C1 on the input side of the first inverter 21, and the sensor G
A capacitance measurement type circuit configuration in which a resistor R2 for removing a DC voltage is connected in parallel between both ends of S, and the oscillation frequency changes in accordance with the capacitance value of the same sensor GS as in FIG. The oscillator 20 is configured.

On the other hand, the movable contacts XC, YC, ZC of the three switches X, Y, Z are the second fixed contacts X1, Y.
1, the sensor GS is inserted in the feedback circuit of the first inverter 21 instead of the resistor R1, and the resistor R2 for removing the DC voltage on the input side of the first inverter 21 is connected. Is shorted by the first switch X,
Since the capacitive element C1 is connected to the input side of the first inverter 21 through the first switch X, the CR oscillator 20 whose oscillation frequency changes corresponding to the electric resistance value of the sensor GS same as that in FIG. Composed.

The pulse output signal from each CR oscillation circuit 20 shown in FIGS. 3 to 5 is supplied to a second Schmitt inverter 22 of the same C-MOS type as the first Schmitt inverter 21, and then from the second Schmitt inverter 22. Generates a pulse voltage of the same frequency F ₀ which is the inverse of the pulse waveform of the first Schmitt inverter 21.

The operation mode of the C-MOS type Schmitt inverters 21 and 22 will be briefly described as follows.
Both Schmitt inverters have two threshold voltages, a high level threshold voltage V _TH and a low level threshold voltage V _TL , and generate a high level output voltage V _H when the input voltage is lower than the high level threshold voltage V _TH. Further, when the input voltage reaches the high level threshold voltage V _TH , the output voltage switches from the high level V _H to the low level V _L , and the low level is maintained until the input voltage drops to the low level threshold voltage V _TL. Of the output voltage V _L is held, and when the input voltage drops to the low level threshold voltage V _TL , the output voltage switches from the low level V _L to the high level V _H. Therefore, C
The R oscillating circuit 20 outputs a pulse voltage having a cycle corresponding to charging / discharging of the capacitance element or the capacitance of the capacitance element and the series circuit of the sensor.

FIG. 6 shows the relationship between the power supply voltage and the consumption current when the resistance is 1 MΩ and the capacitor is 10 μF in the CR oscillation circuit 20 using the C-MOS type Schmitt inverters 21 and 22. From the characteristics of FIG. 6, it is understood that the current consumption is remarkably reduced when the power supply voltage is lowered. For example, when the power supply voltage is reduced from 5V to 1.5V, it can be seen that the current consumption is reduced from about 1 mA to about 2 μA, which is actually 1/500. Therefore, if such a CR oscillating circuit 20 is used in the information measuring device 6 of this embodiment, the current consumption becomes extremely small together with the periodical driving of the information measuring device 6 described above. It is possible to sufficiently perform continuous measurement without power supply using the solar cell 1 and the power supply circuit 2 having a relatively small capacity.

On the other hand, as shown in FIG. 7, the illuminance (amount of light), which is adapted to detect the deterioration of oil, lubricating oil, etc., based on the illuminance or the amount of light incident on a photodetecting element such as a photodiode or phototransistor, The current consumption of the frequency conversion type measuring circuit is also extremely low. This measuring circuit includes a photodiode PD which is a light detecting element, a capacitor C which is a capacitance type load, an analog switch 23 and a first C-MOS type Schmidt inverter 21, and an illuminance (light quantity) -frequency conversion circuit ( Oscillator circuit) 30, and the photodiode PD and the capacitor C are analog switches 2
A current I _P flowing in the photodiode PD proportional to the illuminance or the amount of incident light is stored in the capacitor C via the analog switch 23 and is converted into the voltage V _C. The voltage V _C stored in the capacitor C is the first Schmitt inverter 21 of the C-MOS type.
Is converted into a pulse signal.

On the other hand, the analog switch 23 has two fixed contacts x ₀ and x ₁ and one movable contact x, the movable contact x is connected to the capacitor C, and the first fixed contact x ₀ is connected to the photodiode PD. Connected, and the second fixed contact x ₁ is connected to the discharge resistor R. The movable contact x of the analog switch 23 has the first fixed contact x ₀ when the high level output voltage V _H is applied from the first Schmitt inverter 21 through the control line 21a.
When the low-level output voltage V _L is applied, the movable contact x is connected to the second fixed contact x ₁ .

In the above structure, since the first C-MOS type Schmitt inverter 21 performs the above-mentioned operation, in the initial state in which no current flows in the photodiode PD and therefore no charge is stored in the capacitor C, the first Since the output of the Schmitt inverter 21 is at the high level V _H , the movable contact x of the analog switch 23 is connected to the first fixed contact x ₀ . When the measurement of the amount of light is started, a current I _P flows through the photodiode PD and the capacitor C is charged. When the charging voltage V _C of the capacitor C reaches the high level threshold voltage V _TH of the first Schmitt inverter 21, this Schmitt inverter 2
The output voltage of 1 switches from the high level V _H to the low level V _L. As a result, the movable contact x of the analog switch 23 is switched to the second fixed contact x ₁ side, and the charging voltage V _C of the capacitor _C is discharged via the resistor R. When the charging voltage V _C of the capacitor C drops to the low level threshold voltage V _TL of the first Schmitt inverter 21 due to discharging, the output voltage of the Schmitt inverter 21 switches from the low level V _L to the high level V _H. As a result, the movable contact x of the analog switch 23 is again connected to the first fixed contact x _0, and the charging current flows through the capacitor C. After that, the same operation is repeated, and as a result, the output voltage of the first Schmitt inverter 21, that is, the output voltage V ₁ from the light quantity-frequency conversion circuit 30 is a pulse of frequency F ₀ corresponding to the charging / discharging cycle of the capacitor C. It becomes a waveform.

The pulse output voltage V ₁ of the first Schmitt inverter 21 is supplied to the same C-MOS type second Schmitt inverter 22 as the first Schmitt inverter 21, and the first Schmitt inverter 22 outputs the first Schmitt inverter 22.
A pulse voltage of the same frequency F ₀ is generated by inverting the pulse waveform of the Schmitt inverter 21.

FIG. 8 shows the relationship between the power supply voltage and the consumption current of the measuring circuit using the light quantity-frequency conversion circuit 30 of FIG. It can be seen from the characteristics of FIG. 8 that the current consumption is significantly reduced when the power supply voltage is lowered. For example, if the power supply voltage is 5
It can be seen that when the voltage is reduced from V to 1.5 V, the current consumption is reduced from about 2 mA to about 5 μA, which is actually 1/400. Therefore, such a light quantity-frequency conversion circuit 3
If 0 is used for the information measuring device 6 of this embodiment, the current consumption becomes extremely small together with the periodical driving of the information measuring device 6 described above, and similarly, the solar cell 1 and the power supply circuit having a relatively small power supply capacity are also provided. It is possible to sufficiently perform continuous measurement of the parasitic power supply using 2.

By the way, the power supply circuit 2 and the power feeding control circuit 4
Since the power supply voltage is constantly supplied to these devices, it is necessary to reduce their current consumption as much as possible. In this embodiment,
A CR oscillation using a 3-terminal regulator with a small self-consumption current of about 1 μA for the power supply circuit 2 and a power supply control circuit 4 using a C-MOS type Schmidt inverter as shown in FIGS. It consists of a circuit and a one-shot multivibrator circuit. Further, a solar cell 1 having an output voltage of 3 to 4 V and an output current of 100 to 200 μA is used, and the power supply voltage from the power supply circuit 2 is reduced to 1.5 V by the diode 3 and supplied to the power supply control circuit 4. As shown in FIG. 2, the power supply control circuit 4 supplies a power supply voltage of 1.5 V to the information measuring circuit 6 for a period of 100 milliseconds in a cycle of 10 seconds. As a result, the current consumption of the power supply circuit 2 and the power supply control circuit 4 could be suppressed to 10 μA or less.

On the other hand, the CR oscillation circuit shown in FIGS. 3 to 5 is used as the information measuring circuit 6, and the LED 7 is driven by a pulse signal to cause a blinking optical signal to pass through the optical fiber 9 to the moisture meter of the central information monitoring system. , A thermometer and other measuring devices such as a measuring load, and a microcomputer for a certain time (1
The frequency of the pulse signal is detected from the blinking of the light within 00 milliseconds), and the value of the measured information such as the amount of water and the temperature corresponding to the detected frequency is calculated and displayed. The measured values could be displayed continuously. In this case, the current consumption in the information measuring circuit 6 and the LED drive circuit 8 could be suppressed to several μA.

Further, the blinking optical signal transmitted by the optical fiber 9 is received and supplied to the measuring load, and at the same time, the received blinking optical signal is reflected to separate optical fibers as shown by the broken line in FIG. When the data was transmitted to the solar cell 1 by 10 and the solar cell 1 was operated, continuous measurement of information could be performed without exposing the solar cell 1 to sunlight.

In this way, the solar cell 1 is connected to the optical fiber 10
If it is activated by the light transmitted through (not limited to the received blinking light signal, but it can be sufficiently activated by the transmission of weak light), the whole measuring device must be installed in a dark place. Even in the situation, the measuring apparatus of this embodiment has an advantage that it can continuously measure information without power supply from the outside and without power supply.

In the above embodiments, the case where the present invention is applied to a petroleum plant has been mainly described, but it goes without saying that the non-feeding measuring device according to the present invention is not limited to this. Also, not only information such as the amount of water in crude oil, but also the concentration of water in the gas phase such as humidity, the concentration in the liquid phase such as the amount of water in lubricating oil, and other various gases and liquids The present invention can also be applied to the case of measuring the concentration of a certain component.

Furthermore, the present invention is for measuring the stains or deterioration of various oils and lubricating oils, and the stains or deteriorations of various liquids and gases through which light from a light source can pass (that is, pollutants or deterioration). It is needless to say that the present invention can be applied to the case of measuring the concentration of deterioration products and the like or the case of measuring the illuminance (light quantity) of the reflected light from the measured object that reflects the light from the light source.

The above embodiment is merely an example of the present invention, and the circuit configuration, the elements to be used, etc. can be arbitrarily changed as necessary. For example, the power supply from the power supply control circuit 4 does not have to be performed at a cycle of 10 seconds, and the power supply time is not limited to 100 milliseconds. Further, the power supply voltage lowering means 3 is not limited to the diode, and any voltage lowering means that consumes less current can be used. Further, the CR oscillation circuit may be configured by using an inverter other than the C-MOS type Schmidt inverter or another circuit element, or by using a light emitting element other than the LED, a light other than the photodiode may be used. Of course, a detection element may be used.

[0035]

As described above, according to the passive type measuring device of the present invention, the current consumption can be extremely reduced and the circuit structure can be simplified.
It is possible to reduce the size and cost of the entire apparatus and continuously measure unpowered power using a solar cell and a power supply circuit having a small power supply capacity. Also,
By energizing the solar cell with the light transmitted through the optical fiber, continuous measurement can be performed without power even when installed in a dark place, and the selection range of the installation location of the measurement device is widened. It has a great effect.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a basic configuration of an embodiment of a parasitic measurement device according to the present invention.

FIG. 2 is a waveform diagram showing an example of a power supply voltage supplied from an electric power supply control circuit of the measuring apparatus shown in FIG. 1 to an information measuring circuit.

FIG. 3 is a circuit diagram showing a specific example of a CR oscillation circuit including a sensor that can be applied to the information measurement circuit of the measurement apparatus shown in FIG. 1 as an oscillation frequency determining element.

4 is a circuit diagram showing another specific example of a CR oscillation circuit including a sensor applicable to the information measurement circuit of the measurement apparatus shown in FIG. 1 as an oscillation frequency determining element.

5 is a circuit diagram showing still another specific example of the CR oscillation circuit including a sensor applicable to the information measurement circuit of the measurement apparatus shown in FIG. 1 as an oscillation frequency determining element.

FIG. 6 is a characteristic diagram showing the relationship between the power supply voltage and the consumption current of the CR oscillation circuit shown in FIGS.

7 is a circuit diagram showing a specific example of an illuminance (light quantity) -frequency conversion circuit applicable to the information measuring circuit of the measuring device shown in FIG.

8 is a characteristic diagram showing a relationship between a power supply voltage and a consumption current of the illuminance (light quantity) -frequency conversion circuit shown in FIG.

[Explanation of symbols]

 1 Solar Battery 2 Power Supply Circuit 3 Power Supply Voltage Lowering Means 4 Power Supply Control Circuit 5 Sensor 6 Information Measuring Circuit 7 LED 8 LED Drive Circuit 9, 10 Optical Fiber 20 CR Oscillation Circuit 21, 22 C-MOS Schmitt Inverter 23 Analog Switch 30 Illuminance (Light intensity) -frequency conversion circuit

Claims (3)

[Claims] 1. A solar cell, a power supply circuit that accumulates the output voltage of the solar cell and outputs the voltage at a predetermined voltage, and a power supply that is constantly supplied with an operating voltage through a means for lowering the output voltage from the power supply circuit. A control circuit, an information measuring means for detecting information of an object to be measured, an information measuring circuit operated by power feeding from a power feeding control circuit, and a drive circuit driving a light emitting element by an output signal from the information measuring circuit, An optical transmission means for transmitting an optical signal output from the light emitting element to a measurement load, and the operation voltage is supplied from the power supply control circuit to the information measurement circuit for a very short period of time in a predetermined cycle. Only while the voltage is being supplied, the information measuring circuit outputs a pulse signal corresponding to the information of the measured object to blink the light emitting element, and the blinking optical signal is transmitted through the optical transmission means. Note: A non-feeding type measuring device characterized by being transmitted to a measuring load. 2. The measuring device according to claim 1, wherein the solar cell is energized by light transmitted by an optical transmission means. 3. The information measuring circuit includes the information detecting means as a frequency determining element and C as an active element.
The measuring device according to claim 1 or 2, wherein the measuring device comprises a CR oscillation circuit including a MOS type Schmitt inverter.