JP3999695B2 - Sensor measurement system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensor measurement system for measuring a physical quantity applied from each measurement object at each measurement position far away from each other with a fiber measurement sensor.
[0002]
[Prior art]
When pressure is applied to the outer peripheral surface of the optical fiber or when the optical fiber is locally bent, the transmission loss of light in the optical fiber changes. Further, even when the optical fiber is locally heated and cooled, the light transmission loss changes. A fiber measurement sensor using such physical characteristics of an optical fiber is proposed in Patent Document 1, for example.
[0003]
FIGS. 7A and 7B are schematic cross-sectional views of the fiber measurement sensor 1 as the water immersion detection sensor proposed in Patent Document 1. FIG. As shown to Fig.7 (a), the fiber 3 is penetrated by the container 2 in which many water-permeable holes were formed. In the container 2, the water-absorbing expansion material 4 is accommodated, and a convex portion 5 is formed. When the surroundings of such a fiber measurement sensor 1 are filled with water, the water absorbing and expanding material 4 absorbs water and expands. Then, as shown in FIG. 7B, the fiber 3 is lifted, abuts against the convex portion 5, and is locally bent. As a result, the transmission loss of the fiber 3 increases. Therefore, if the change in the transmission loss can be detected by any method, the fiber measurement sensor 1 can detect flooding.
[0004]
This fiber measurement sensor 1 is an inundation detector for communication optical cables because it does not require electric power, is not easily affected by lightning, and can be installed on a remote measurement target using an optical fiber. The use of is proposed. In addition to inundation detection, it is also applied to the measurement of the water level at each position of the river, the distortion measurement of tunnels and embankments, and the snow gauge and rain gauge in remote areas.
[0005]
A sensor measurement system that measures a physical quantity (water immersion amount) applied from each measurement object at each measurement position (each position of a communication optical cable) far away from each other using the fiber measurement sensor 1 having such a configuration is, for example, shown in FIG. The configuration is as shown in FIG.
[0006]
In FIG. 8, a pulsed waveform of measurement light a having a constant pulse width is applied to an optical fiber 7 at a constant period Ta from an optical pulse tester (hereinafter abbreviated as OTDR) 6. Each measurement position of the optical fiber 7 (each distance d from the OTDR 6) ₁ , D ₂ , D _Three , ..., d _n ), A plurality (n) of fiber measurement sensors 1 provided in the measurement object are inserted. Specifically, the fiber 3 in FIG. 7A is inserted at each measurement position of the optical fiber 7. A terminator 8 is attached to the other end of the optical fiber 7. Further, the OTDR 6 is connected to a measurement control device 9 that controls the measurement operation of the entire sensor measurement system.
[0007]
In the sensor measurement system having such a configuration, when the measurement light a having a pulse wave shape is applied from the OTDR 6 to the optical fiber 7 with a constant period Ta, the measurement light a is propagated on the optical fiber 7 toward the terminator 8. In this propagation process, each distance d ₁ , D ₂ , D _Three , ..., d _n It passes through the fiber 3 of each fiber measuring sensor 1 installed at the position.
[0008]
Then, in the process in which the measurement light a propagates through the optical fiber 7 and each position in the fiber 3 of each fiber measurement sensor 1, backscattered light propagating in the OTDR 6 direction is generated. Each backscattered light generated at each position is multiplexed and input to the OTDR 6 as reflected light b. In the OTDR 6, the reflected light b obtained by collecting the backscattered light generated at each input position is shown in FIGS. 9 and 10, the horizontal axis is the distance d from the OTDR 6, and the vertical axis is the reflected light level (light (Intensity) is converted to a reflected waveform c and sent to the measurement control unit 9.
[0009]
In the reflected waveform c shown in FIGS. 9 and 10, as the distance d from the OTDR 6 becomes longer, the attenuation increases and the level of the reflected waveform c decreases.
[0010]
FIG. 9 shows a reference waveform e which is a reflected waveform c output from the OTDR 6 in a state where physical quantities such as stress and heating / cooling are not applied to each fiber measurement sensor 1. FIG. 10 shows a measurement waveform f that is a reflection waveform c output from the OTDR 6 when each fiber measurement sensor 1 is actually measured in the measurement environment.
[0011]
When comparing the reference waveform e of FIG. 9 and the measurement waveform f of FIG. ₁ When some physical quantity is applied to the fiber measurement sensor 1 at, the transmission loss of the fiber 3 increases, and this distance d in the optical fiber 7 ₁ The level of backscattered light from each farther position is reduced. As a result, the distance d in the measurement waveform f ₁ The reflected light level at each further distant position is lowered.
[0012]
Accordingly, the measurement control device 9 is configured so that the distance d of each fiber measurement sensor 1 in the reference waveform e in FIG. ₁ , D ₂ , D _Three , ..., d _n Each reference level L _S1 , L _S2 , L _S3 ..., L _Sn Remember. Then, the measurement control device 9 sends each reference level L _S1 , L _S2 , L _S3 ..., L _Sn And the distance d of each fiber measurement sensor 1 in the measurement waveform f of FIG. ₁ , D ₂ , D _Three , ..., d _n Each measurement level L ₁ , L ₂ , L _Three ..., L _n And each difference (L _S1 -L ₁ ), (L _S2 -L ₂ ), (L _S3 -L _Three ), ..., (L _Sn -L _n ) And each distance d at which this difference is equal to or greater than a predetermined threshold value ₁ , D ₂ , D _Three , ..., d _n It is determined that some physical quantity exceeding the allowable value is applied to the fiber measurement sensor 1 at the shortest distance d from the OTDR 6.
[0013]
[Patent Document 1]
Japanese Examined Patent Publication No. 7-69248
[0014]
[Problems to be solved by the invention]
However, the sensor measurement system using the plurality of fiber measurement sensors 1 and the OTDR 6 shown in FIG.
[0015]
That is, the difference between each reference level and each measurement level obtained at the time of measurement is calculated, and the fiber measurement sensor having the shortest distance d from OTDR 6 among the distances in which this difference is equal to or greater than a predetermined threshold. It is determined that some physical quantity exceeding the allowable value is applied to 1.
[0016]
In this method, each reference level and each measurement level at each distance farther than the fiber measurement sensor 1 having the shortest distance d from the OTDR 6 among the distances in which the difference is equal to or greater than a predetermined threshold value. The differences are all equal to or greater than the threshold value as shown in FIG. 10 regardless of whether or not an allowable physical quantity is applied to each fiber measurement sensor 1.
[0017]
Therefore, each distance d of the optical fiber 7 ₁ , D ₂ , D _Three , ..., d _n When a physical quantity more than an allowable value is simultaneously applied to a plurality of fiber measurement sensors 1 among n fiber measurement sensors 1 inserted in the position, OTDR 6 of these plurality of fiber measurement sensors 1 It is determined that an allowable physical quantity is applied to only one fiber measurement sensor 1 with the shortest distance d, and the remaining fiber measurement sensors 1 are normal because an excessive physical quantity is not applied. Misjudged.
[0018]
The present invention has been made in view of such circumstances, and by calculating the difference waveform between the reference waveform and the measurement waveform and the amount of change in the difference at each distance in the difference waveform, each optical fiber An object of the present invention is to provide a sensor measurement system capable of accurately evaluating a physical quantity applied to each fiber measurement sensor even when a physical quantity is simultaneously applied to a plurality of fiber measurement sensors inserted at distance positions.
[0019]
[Means for Solving the Problems]
In order to solve the above-described problems, a sensor measurement system according to the present invention includes a plurality of fiber measurement sensors that are provided in measurement objects that are spaced apart from each other and that change according to a physical quantity to which transmission loss with respect to incident light is applied. An optical fiber that connects fiber measurement sensors in series, and an optical pulse that measures and outputs a reflected waveform as a function of the distance from one end of the optical fiber by applying measurement light having a pulse waveform from one end of the optical fiber A test waveform, a reference waveform memory that stores a reflected waveform output from the optical pulse tester as a reference waveform when no physical quantity is applied to each fiber measurement sensor, and an optical pulse tester that performs measurement for each measurement target. The difference calculation unit that calculates the difference waveform between the reference waveform and the measurement waveform using the output reflected waveform as the measurement waveform, and the difference calculation unit In minute waveform Amount of change between immediately before and after the placement distance of each fiber measurement sensor The difference change amount As The difference change amount calculation unit to be calculated, and each difference change amount calculation unit calculated by this difference change amount calculation unit Arrangement Based on the difference change in distance, The arrangement distance And a physical quantity evaluation means for evaluating a physical quantity applied to the fiber measurement sensor disposed in the.
[0020]
In the sensor measurement system configured as described above, a reference waveform output from the OTDR in a state where no physical quantity is applied to each fiber measurement sensor is stored in the reference waveform memory.
[0021]
Then, a differential waveform between the measurement waveform output from the OTDR and the reference waveform at the time of measurement is calculated. Further, the change amount of the difference at each distance in the difference waveform is calculated. When a physical quantity such as pressure is applied to each fiber measurement sensor inserted at each distance of the optical fiber, the level (reflected light level) at the corresponding distance of the measurement waveform output from the OTDR rapidly decreases.
[0022]
A sudden drop in the level (reflected light level) at each distance in this measured waveform is detected by differentiating the differential waveform by distance, in other words, by calculating the amount of change in the differential waveform at each distance. Is possible. That is, even if a physical quantity such as pressure is applied to each fiber measurement sensor at a plurality of distances on the optical fiber, they can be detected independently.
[0023]
The magnitude of the physical quantity such as pressure applied to each fiber measurement sensor corresponds to the rapidity (change) of the change (decrease) in the level (reflected light level) at the corresponding distance in the measurement waveform. In other words, it can be converted from the amount of change in the difference at the corresponding distance.
[0024]
In another sensor measurement system according to the present invention, a plurality of fiber measurement sensors that are provided in measurement objects that are separated from each other and change according to a physical quantity to which a transmission loss with respect to incident light is applied, and each of the fiber measurement sensors are provided. An optical fiber tester that applies measurement light having a pulse waveform from one end of the optical fiber and measures and outputs a reflected waveform as a function of the distance from the optical fiber; A reference waveform memory that stores a reflected waveform output from the optical pulse tester as a reference waveform when no physical quantity is applied to each fiber measurement sensor, and output from the optical pulse tester during measurement for each measurement target A difference calculation unit that calculates a difference waveform between the reference waveform and the measurement waveform using the reflected waveform as a measurement waveform, and a difference wave calculated by the difference calculation unit In Amount of change between immediately before and after the placement distance of each fiber measurement sensor The difference change amount As A difference change amount calculation unit to be calculated, a plurality of thresholds according to the degree of abnormality with respect to the difference change amount, and a threshold memory for storing a display format when the difference change amount is equal to or greater than the corresponding threshold, and stored in the threshold memory Each using multiple thresholds Arrangement Determining the amount of change in distance as normal or multiple abnormalities, The arrangement distance A threshold comparison / determination unit that outputs a normal quantity or a plurality of abnormalities of the physical quantity applied to the fiber measurement sensor disposed in the optical fiber, and a determination result of the physical quantity applied to each fiber measurement sensor determined by the threshold comparison / determination unit A measurement result history memory for storing a plurality of measurements, and a normal or a plurality of abnormalities of each fiber measurement sensor stored in the measurement result history memory in accordance with a display format stored in the threshold memory. And a display editing unit for displaying in time series.
[0025]
In the sensor measurement system configured as described above, even if a physical quantity such as pressure is applied to each fiber measurement sensor at a plurality of distances on the optical fiber according to the same operation principle as that of the above-described invention, they are independently applied. It can be detected.
[0026]
Furthermore, the sensor measurement system of the present invention is provided with a plurality of threshold values according to the degree of abnormality with respect to the difference change amount and a threshold memory for storing a display format when the difference change amount is equal to or more than the corresponding threshold value. . Then, the calculated change amount of each difference is determined to be normal or a plurality of abnormalities. Further, the determination result of the physical quantity applied to each fiber measurement sensor is stored in the measurement result history memory over a plurality of measurements. Then, the normality or a plurality of abnormalities of each fiber measuring sensor is displayed in time series on the display according to the display format designated by the abnormalities.
[0027]
Therefore, the monitor of this sensor measurement system can confirm at a glance the time series history of the degree of normality or abnormality of each measurement object measured by each fiber measurement sensor.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a sensor measurement system according to an embodiment of the present invention. The same parts as those of the conventional sensor measurement system shown in FIG. In the sensor measurement system of this embodiment, the case where the water level (measurement object) in each position of the river is measured will be described as an example.
[0029]
Measurement light a having a pulse shape having a constant pulse width is applied to the optical fiber 7 at a constant period Ta from a pulse light source 20 of an OTDR (optical pulse tester) 10. Each measurement position of the optical fiber 7 (each distance d from the OTDR 10) ₁ , D ₂ , D _Three , ..., d _n ), A plurality (n) of fiber measurement sensors 11 provided in each measurement target (water level at each position of the river) are inserted. In the fiber measurement sensor 11, when a water pressure corresponding to the water level is applied to the fiber incorporated in the fiber measurement sensor 11, the transmission loss of the fiber changes. A terminator 8 is attached to the other end of the optical fiber 7.
[0030]
When the pulse-wave-shaped measurement light a is applied from the OTDR 10 to the optical fiber 7 at a constant period Ta, the measurement light a propagates on the optical fiber 7 toward the terminator 8. In this propagation process, the measurement light a is each distance d ₁ , D ₂ , D _Three , ..., d _n It passes through the fiber of each fiber measurement sensor 11 installed at the position. Then, backscattered light propagating in the OTDR 10 direction is generated in the process in which the measurement light a propagates through each position in the fiber of the optical fiber 7 and each fiber measurement sensor 11. Each backscattered light generated at each position is multiplexed and input to the OTDR 10 as reflected light b.
[0031]
The reflected light b, which is input into the OTDR 10 and collects the backscattered light generated at each position, enters the photoelectric converter 14 in the reflected waveform measurement unit 13 via the optical coupler 12. The reflected light b is converted into an electric signal by the photoelectric converter 14, amplified by the amplifier 15, converted into a digital electric signal by the A / D converter 16, and input to the averaging circuit 17.
[0032]
The averaging circuit 17 averages the electric signal of the reflected light b of the optical fiber 7 inputted for every fixed period Ta for a plurality of periods Ta, and the horizontal axis shown in FIGS. And a reflected waveform g having the vertical axis as the reflected light level is calculated and sent to the control unit 18.
[0033]
The control unit 18 displays and outputs the averaged reflected waveform g to the display device 19 and sends it to the information processing device 21 configured by, for example, a personal computer (PC). Further, the control unit 18 sends an instruction to the pulse generator 20a to control the pulse width and period Ta of the pulse signal applied from the pulse generator 20a to the pulse light source 20. The pulsed light source 20 outputs pulsed waveform measuring light a having the pulse width and period Ta of the input pulse signal to the optical fiber 7.
[0034]
In the information processing apparatus 21 configured by a personal computer (PC), the input reflected waveform g is temporarily stored in the measurement control unit 22. In the reference waveform memory 23, the reflected waveform g measured in a state where no physical quantity such as stress is applied to each fiber measurement sensor 11 in this sensor measurement system is stored as the reference waveform e shown in FIG. ing. On the other hand, in the measurement waveform memory 24, the measurement waveform f shown in FIG. 2B, which is the reflected waveform g output from the OTDR 10 during actual measurement, is temporarily stored in each measurement sensor 11 in the measurement environment. Is done.
[0035]
Comparing the reference waveform e in FIG. 2 (a) with the measured waveform f in FIG. 2 (b), in this embodiment, the distance d ₁ , Distance d _Three A certain physical quantity (water pressure) is applied to each of the fiber measurement sensors 11 in FIG. 1, the fiber transmission loss in the fiber measurement sensor 11 increases, and the distance d in the optical fiber 7 increases. ₁ The level of backscattered light from each farther position is reduced, and the distance d in the optical fiber 7 is further reduced. _Three The level of backscattered light from each farther position is further reduced. As a result, the reflected light level L in the measurement waveform f is equal to the distance d. ₁ , Distance d _Three Suddenly drops in
[0036]
The difference calculation unit 25 subtracts the measurement waveform f shown in FIG. 2B stored in the measurement waveform memory 24 from the reference waveform e shown in FIG. The differential waveform h shown in 2 (c) is calculated and written into the differential waveform memory 26.
[0037]
In this embodiment, the reflected light level L of the measurement waveform f is the distance d. ₁ , Distance d _Three The difference value of the difference waveform h is the distance d. ₁ , Distance d _Three In steps, the other parts are flat.
[0038]
The difference change amount calculation unit 27 is configured so that each distance d at which each fiber measurement sensor 11 in the difference waveform h shown in FIG. 2C stored in the difference waveform memory 26 is installed. ₁ , D ₂ , D _Three , ..., d _n The change amount E of the difference shown in FIG. ₁ , E ₂ , E _Three ... E _n Is calculated and written to the difference change amount memory 28.
[0039]
Specifically, the differential waveform h, which is a function of the distance d shown in FIG. 2C, is differentiated by the distance d to obtain a differential waveform i shown in FIG. 2D, and each distance in the differential waveform i is obtained. d ₁ , D ₂ , D _Three , ..., d _n The difference value E ₁ , E ₂ , E _Three ... E _n It is said. Each difference change amount E ₁ , E ₂ , E _Three ... E _n Is each distance d ₁ , D ₂ , D _Three , ..., d _n This corresponds to the physical quantity (water pressure corresponding to the water level in this embodiment) applied to each of the fiber measurement sensors 11 arranged in the.
[0040]
In this embodiment, the distance d ₁ , Distance d _Three Change E ₁ , E _Three Is very large and other distances d ₂ , D _n Change E ₂ , E _n Is almost zero.
[0041]
The difference change amount display unit 29 stores the difference change amount E of each fiber measurement sensor 11 written in the difference change amount memory 28. ₁ , E ₂ , E _Three ... E _n And the water level D is a physical quantity ₁ , D ₂ , D _Three ... D _n And output to the display 30.
[0042]
As shown in FIG. 3, the threshold memory 32 includes a plurality of threshold values X corresponding to the degree of abnormality with respect to the difference change amount E. ₁ , X ₂ , X _Three The display format when the difference change amount E is equal to or greater than the corresponding threshold is stored.
In this embodiment, three types of abnormalities of “limit abnormality”, “normal abnormality”, and “minor abnormality” and “normal” are set, and the respective threshold values, “red”, “orange” are set. , “Yellow”, and “white” display colors are set.
[0043]
Each threshold value X in the threshold value memory 32 ₁ , X ₂ , X _Three And the display format (display color) can be arbitrarily set by the administrator of the sensor measurement system by operating the threshold setting unit 33.
[0044]
The threshold comparison determination unit 31 includes a plurality of threshold values X stored in the threshold memory 32. ₁ , X ₂ , X _Three The difference change amount E of each fiber measurement sensor 11 stored in the difference change amount memory 28 using ₁ , E ₂ , E _Three ... E _n Are determined as three types of abnormalities, “normal” or “limit abnormality”, “normal abnormality”, and “minor abnormality”, and the determination result is normal or a plurality of abnormalities of the physical quantity applied to each fiber measurement sensor Are additionally written in the measurement result history memory 34.
[0045]
As a result, the determination result of the physical quantity applied to each fiber measurement sensor 11 determined by the threshold comparison determination unit 31 is stored in the measurement result history memory 34 in time series over a plurality of measurement executions. .
[0046]
The display editing unit 35 displays the normality or a plurality of abnormalities of each fiber measurement sensor 11 stored in the measurement result history memory 34 in a time series on the display 30 with the display color stored in the threshold memory 32. . In FIG. 4, each fiber measurement sensor (A ₁ , A ₂ , A _Three , A _Four A ... _n ) The normal or abnormal history table 36 for every 11 is shown.
[0047]
As shown in the history table 36 of FIG. 4, the monitor can check the history of normality or abnormality for each fiber measurement sensor 11 by looking at the display 30.
[0048]
The difference change amount display unit 29, the threshold comparison determination unit 31, and the threshold memory 32 are arranged at each distance position d based on the difference change amount E at each distance d calculated by the difference change amount calculation unit 27. The physical quantity evaluation means for evaluating the physical quantity D applied to the fiber measurement sensor 11 is configured.
[0049]
And the measurement control part 22 of the information processing apparatus 21 performs the setting process of a reference waveform according to the flowchart shown in FIG.
First, each fiber measurement sensor 11 is brought into a no-load state where no physical quantity is applied. Specifically, the worker raises each fiber measurement sensor 11 from the water surface at each position of the river (S1). Next, the OTDR 10 is activated to obtain a reflected waveform g (S2). The reflected waveform g is written into the reference waveform memory 23 as the reference waveform e shown in FIG. 2A (S3).
[0050]
In addition, the measurement control unit 22 of the information processing apparatus 21 is in a state where each fiber measurement sensor 11 is actually placed in a measurement environment according to the flowchart shown in FIG. The evaluation process of the water level (physical quantity) in the state installed in each measurement position is executed.
[0051]
In this state, the OTDR 10 is activated to obtain a reflected waveform g (Q1). This reflected waveform g is written into the measured waveform memory 24 as a measured waveform f shown in FIG. 2B (Q2). Next, the difference calculation unit 25 is activated, the measurement waveform f is subtracted from the reference waveform e, the difference waveform h shown in FIG. 2C is calculated, and written to the difference waveform memory 26 (Q3).
[0052]
The difference change amount calculation unit 27 is activated, and the fiber measurement sensor 11 in the difference waveform h is provided. ₁ , D ₂ , D _Three , ..., d _n The change amount shown in FIG. 2D at one of the n distances is obtained and written as the difference change amount E into the difference change amount memory 28 (Q4). The difference change amount display unit 29 is activated, the difference change amount E is converted into a water level D which is a physical quantity, and is displayed on the display 30 (Q5).
[0053]
The threshold value comparison / determination unit 31 is activated, and this difference change amount E is set to each threshold value X in the threshold value memory 32. ₁ , X ₂ , X _Three Compared with, normal / abnormal and the degree of abnormality are determined (Q6). This determination result (measurement result) is added and written to the measurement result history memory 34 (Q7).
[0054]
If there is an uncalculated distance in which the fiber measurement sensor 11 is provided in the difference waveform h (Q8), the process returns to Q4, and the difference change amount E with respect to the corresponding distance is calculated.
[0055]
All distances d at which the fiber measurement sensor 11 is provided in the differential waveform h ₁ , D ₂ , D _Three , ..., d _n When the writing process of the determination result (measurement result) in the measurement result history memory 34 is completed (Q8), the display editing unit 35 is activated and each determination result (measurement result) stored in the measurement result history memory 34 is activated. Is edited (Q9). The display editing unit 35 displays a time series history of normality or a plurality of abnormalities of each fiber measurement sensor 11 in a display color specified in the abnormalities in the history table 36 format shown in FIG. (Q10).
[0056]
In addition, in the flowchart of this FIG. 6, d provided with the fiber measurement sensor 11 in the differential waveform h. ₁ , D ₂ , D _Three , ..., d _n The normal / abnormal and the degree of abnormality were determined for each of the n distances of n. ₁ , D ₂ , D _Three , ..., d _n Total difference change E in ₁ , E ₂ , E _Three ... E _n It is also possible to determine the normality / abnormality and the degree of abnormality collectively.
[0057]
In the sensor measurement system configured in this way, each distance d from the OTDR 10 of the optical fiber 7 ₁ , D ₂ , D _Three , ..., d _n The reference waveform e output from the OTDR 10 in a state where no physical quantity (water pressure corresponding to the water level) is applied to each of the fiber measurement sensors 11 provided in is stored in the reference waveform memory 23.
[0058]
Then, as shown in FIGS. 2A, 2B, and 2C, a difference waveform h between the measurement waveform f output from the OTDR 10 and the reference waveform e when the measurement is performed on each measurement target (water level) is calculated. The Further, as shown in FIG. 2D, each distance d in the differential waveform h ₁ , D ₂ , D _Three , ..., d _n Difference change amount E ₁ , E ₂ , E _Three ... E _n Is calculated.
[0059]
As mentioned above, each distance d ₁ , D ₂ , D _Three , ..., d _n Difference change amount E ₁ , E ₂ , E _Three ... E _n Corresponds to a physical quantity such as water pressure applied to the fiber measurement sensor 11 inserted at the corresponding distance position. ₁ , E ₂ , E _Three ... E _n From each water level D ₁ , D ₂ , D _Three ... D _n Are individually calculated and displayed on the display 30.
[0060]
Thus, even if physical quantities such as pressure are applied to each fiber measurement sensor 11 at a plurality of distances on the optical fiber 7, these physical quantities can be detected independently.
[0061]
Further, in the threshold memory 32, a plurality of threshold values X corresponding to normal and abnormal levels with respect to the difference change amount E are stored. ₁ , X ₂ , X _Three In addition, display colors of “white”, “red”, “orange”, and “yellow” when the difference change amount E is normal and each threshold value or more are stored. Further, the determination result of the physical quantity applied to each fiber measurement sensor 11 is stored in the measurement result history memory 34 over a plurality of measurements.
[0062]
Then, the normality or a plurality of abnormalities of each of the fiber measurement sensors 11 is displayed on the display device 30 in time series as the history table 36 shown in FIG. 4 according to the display color designated by the abnormalities.
[0063]
Therefore, the monitor of this sensor measurement system can confirm at a glance the time-series history of each measurement object (water level at each position in the river) measured by each fiber measurement sensor 11 as normal or abnormal.
[0064]
In addition, this invention is not limited to embodiment mentioned above. In the sensor measurement system of the embodiment, the water level at each position of the river was measured. However, in addition to the water level measurement, inundation detection at each position of the communication optical cable, tunnel and levee strain measurement, snow meter and rainfall at remote locations Needless to say, it can be applied to totals.
[0065]
【The invention's effect】
As described above, in the sensor measurement system of the present invention, the difference waveform between the reference waveform and the measurement waveform and the change amount of the difference at each distance in the difference waveform are calculated, and the fiber measurement sensor is calculated from the difference change amount. The physical quantity applied to is evaluated.
[0066]
Therefore, even if a physical quantity is simultaneously applied to a plurality of fiber measurement sensors inserted at each distance position of the optical fiber, the physical quantity applied to each fiber measurement sensor can be accurately evaluated.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of a sensor measurement system according to an embodiment of the present invention.
FIG. 2 is a waveform diagram for explaining a measurement principle in the sensor measurement system of the embodiment.
FIG. 3 is a view showing stored contents of a threshold memory formed in the sensor measurement system of the embodiment.
FIG. 4 is a diagram showing a history table displayed on the display of the sensor measurement system of the embodiment.
FIG. 5 is a flowchart showing a reference waveform setting process operation in the information processing apparatus of the sensor measurement system according to the embodiment;
FIG. 6 is a flowchart showing a measurement processing operation in the information processing apparatus of the sensor measurement system according to the embodiment;
FIG. 7 is a diagram showing an example of a fiber measurement sensor
FIG. 8 is a block diagram showing a schematic configuration of a conventional sensor measurement system.
FIG. 9 is a diagram showing a reference waveform measured by OTDR
FIG. 10 is a diagram showing a measurement waveform measured by OTDR
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 7 ... Optical fiber, 8 ... Terminator, 10 ... OTDR (optical pulse tester), 11 ... Fiber measurement sensor, 12 ... Optical coupler, 13 ... Reflection waveform measurement part, 17 ... Averaging circuit, 18 ... Control part, 19 , 30 ... Display, 21 ... Information processing device, 22 ... Measurement control unit, 23 ... Reference waveform memory, 24 ... Measurement waveform memory, 25 ... Difference calculation unit, 26 ... Difference waveform memory, 27 ... Difference change amount calculation unit, 28 ... Difference change amount memory, 29 ... Difference change amount display unit, 31 ... Threshold comparison determination unit, 32 ... Threshold memory, 33 ... Threshold setting unit, 34 ... Measurement result history memory, 35 ... Display editing unit, 36 ... History table

Claims (2)

A plurality of fiber measurement sensors (11) provided in each measurement object spaced apart from each other and changing according to a physical quantity to which a transmission loss with respect to incident light is applied;
An optical fiber (7) for connecting the fiber measuring sensors in series;
An optical pulse test in which measurement light (a) having a pulse waveform is applied from one end of the optical fiber, and a reflected waveform (g) as a function of the distance (d) from one end of the optical fiber is measured and output. A vessel (10);
A reference waveform memory (23) for storing, as a reference waveform (e), a reflected waveform (g) output from the optical pulse tester in a state where no physical quantity is applied to each of the fiber measurement sensors;
A difference calculation unit that calculates a difference waveform (h) between the reference waveform and the measurement waveform, with the reflected waveform (g) output from the optical pulse tester when the measurement is performed on each measurement target as the measurement waveform (f) (25) and
Difference change amount calculator for calculating an amount of change between immediately before and after placement distance of the difference calculation unit wherein each fiber measuring sensor in the calculated difference waveform as a difference variation (E) and (27),
Physical quantity evaluation means (29, 31, 32) for evaluating the physical quantity applied to the fiber measuring sensor arranged at the arrangement distance based on the difference change quantity at each arrangement distance calculated by the difference change quantity calculation unit. When,
Sensor measurement system with A plurality of fiber measurement sensors (11) provided in each measurement object spaced apart from each other and changing according to a physical quantity to which a transmission loss with respect to incident light is applied;
An optical fiber (7) for connecting the fiber measuring sensors in series;
An optical pulse test in which measurement light (a) having a pulse waveform is applied from one end of the optical fiber, and a reflected waveform (g) as a function of the distance (d) from one end of the optical fiber is measured and output. A vessel (10);
A reference waveform memory (23) for storing, as a reference waveform (e), a reflected waveform (g) output from the optical pulse tester in a state where no physical quantity is applied to each of the fiber measurement sensors;
A difference calculation unit that calculates a difference waveform (h) between the reference waveform and the measurement waveform, with the reflected waveform (g) output from the optical pulse tester when the measurement is performed on each measurement target as the measurement waveform (f) (25) and
Difference change amount calculator for calculating an amount of change between immediately before and after placement distance of the difference calculation unit wherein each fiber measuring sensor in the calculated difference waveform as a difference variation (E) and (27),
A threshold memory (32) for storing a plurality of thresholds according to the degree of abnormality with respect to the difference change amount and a display format when the difference change amount is equal to or greater than a corresponding threshold value;
Using a plurality of threshold values stored in the threshold memory, a difference change amount at each arrangement distance is determined to be normal or a plurality of abnormalities, and a determination result is applied to a fiber measurement sensor arranged at the arrangement distance. A threshold comparison / determination unit (31) that outputs the normal physical quantity as normal or a plurality of abnormalities;
A measurement result history memory (34) for storing the determination result of the physical quantity applied to each fiber measurement sensor determined by the threshold comparison determination unit over a plurality of measurement implementations;
A display editing unit (35) that displays the normality or the plurality of abnormalities of each fiber measurement sensor stored in the measurement result history memory in time series on the display (30) according to the display format stored in the threshold memory. And a sensor measurement system.

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