JPH1019956A - Method and equipment for discriminating object to be discriminated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operation efficiency without necessitating an operation of switchover of signals and discrimination of conductors even when two discriminating methods of a voltage discrimination system and a current discrimination system are used in combination simultaneously. SOLUTION: In a method wherein signals of different frequencies are impressed from a transmitter 20 on a target cable 1 out of a plurality of cables having a plurality of conductors 2 and a signal component of each frequency is detected selectively on the desired reception end side of the cables in a plurality so as to discriminate the target cable, voltage signals of specified frequencies supplied with a constant voltage from oscillating circuits 11 and 12 and a constant-current signal of a specified frequency supplied with a constant current from a supply part 13 are synthesized by a synthesizing circuit 14 and impressed directly on the same conductor 2a of the target cable, while the synthesized signal is detected from the cable selected by a receiver 20 and discrimination is made as to whether the cable is the target cable or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object to be identified which is laid between devices and which identifies a target cable to be identified among a plurality of conductive objects, for example, a plurality of cables, each of which includes a plurality of conductors. The present invention relates to a method and an apparatus for identifying an object.

[0002]

2. Description of the Related Art Conventionally, this kind of cable is composed of a communication cable, a power cable and the like, and is laid in large numbers through a trough or a cable duct for a tunnel or a railway. When maintaining a specific cable or removing an unnecessary cable from these cables, it is necessary to identify a target cable from a plurality of cables at a desired position far from a certain cable end.

Therefore, as a conventional identification means, first, a plurality of frequency signals are supplied to a target cable using an electrostatic coupling method, and a signal electrode is applied to one cable selected by a cable laying line. The target cable is detected by determining whether the frequency signal can be detected from the cable. Next, switching to the current identification method supplies a constant current signal to the conductor of the target cable, and detects whether the constant current signal is flowing through the selected cable to identify the target cable.

[0004]

However, in the above switching method, the signal switching cycle is usually set to several hundred msec to several seconds, and the work time for identifying one cable is 5 to 5 times the switching cycle. More than 6 times
There was a problem that the work efficiency at the time of cable identification became very poor.

A method of simultaneously supplying a voltage signal and a current signal from the same transmitter to different conductors of the same cable can also be considered. In this method, each supply conductor is separated to separate the voltage signal and the current signal. To detect
The conductor identification work of the cable is required at both ends of the target cable, which requires a separate device for identifying the conductor, which increases the cost and lowers the work efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. Even when two identification methods, that is, a voltage identification method and a current identification method, are used at the same time, the operation can be performed without requiring signal switching operation and conductor identification. An object of the present invention is to provide a method and an apparatus for identifying an object to be identified, which can improve the efficiency. It is another object of the present invention to accurately measure loop resistance.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a conductive object including a plurality of cables each including a plurality of conductors therein is provided.
A signal having a different frequency is applied from a transmitting end to an object to be identified (a target cable) to be identified, and signal components of the respective frequencies are selectively detected at a desired receiving end of the plurality of cables and the target signal is detected. In the method for identifying an object to be identified for identifying a cable, a first signal (constant voltage signal) of at least one specific frequency supplied with a constant voltage and at least one specific frequency different from the frequency of the constant voltage signal And a second signal (constant current signal) supplied with a constant current, and directly applied to a desired same conductor of the target cable. In other words, a constant voltage signal and a constant current signal having different frequencies are combined, and applied to the same conductor of the target cable directly from the transmitting end, and the receiving end of the cable receives an electrostatic charge from a cable selected from a plurality of cables. Using the coupling, the constant voltage signal is detected, and the cable is clamped using a clamp method to detect the constant current signal, thereby identifying whether the selected cable is the target cable.

According to a second aspect of the present invention, the transmission end and the reception end are grounded to form a feedback loop of the constant current signal, and a loop resistance of the target cable is monitored, and when the loop resistance is within a predetermined range. And controlling the current value of the constant current signal to a constant value. In other words, in order to reduce the power supply voltage, the constraint that the loop resistance is within a certain range is necessary, and only when the loop resistance is within that range, the constant current signal is accurately controlled to a certain value. I do.

According to a third aspect of the present invention, a signal having a different frequency is applied from a transmitter to a target cable from among a plurality of cables each including a plurality of conductors therein, and a signal component of each frequency is applied to a desired cable of the plurality of cables. In a device for identifying an object to be identified, which is detected at a receiving end and identifies the target cable, the transmitter includes a constant voltage supply unit that supplies a first signal of at least one specific frequency with a constant voltage; A constant current supply unit that supplies a second signal of at least one specific frequency different from the frequency of the first signal at a constant current, and the first and second signals (the constant voltage signal and the constant current signal) that are supplied, Combining means for combining and applying directly to the same desired conductor of the target cable. That is, the transmitter directly applies a composite signal of a constant voltage signal and a constant current signal having different frequencies to the same conductor of the target cable, and the receiver is selected from a plurality of cables at the receiving end side of the cable. A signal electrode is applied to the cable, and a constant voltage signal of the specific frequency is detected by coupling capacitance between the signal electrode and the cable conductor, and the cable is clamped by a clamp type current sensor (clamper). The constant current signal of the specific frequency is detected by using the amperage integration principle, and whether or not the selected cable is the target cable is identified.

According to a fourth aspect of the present invention, a loop forming means for forming a feedback loop of the constant current signal by grounding a transmitting end and a receiving end from the transmitter, and the target cable at a transmitting end side from the transmitter. And a control means for monitoring the loop resistance and controlling the current value of the constant current signal to a constant value according to the loop resistance. That is, the control means controls the constant current signal that fluctuates due to the loop resistance to a constant value.

According to a fifth aspect of the present invention, the transmitter includes a loop resistance indicator, detects a voltage corresponding to the second signal supplied with the constant current, and determines a loop resistance value proportional to the voltage value. Measure and display. In other words, by quantitatively measuring and displaying the loop resistance value with the loop resistance display,
To be able to select appropriate ground resistance improvement measures.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for identifying an object to be identified according to the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an identification device using the identification method of an object to be identified according to the present invention. In the figure, a target cable 1 to be identified is, for example, a signal cable having a plurality of core wires 2 inside and covering the outer periphery thereof with an insulating layer 3. The target cable 1 is one of a plurality of cables laid between devices via a trough, a duct, or the like.

The discriminating apparatus according to the present embodiment is configured such that one end of a conductor (core wire or shield layer) of a target cable 1 (hereinafter referred to as a “transmission end”).
And a transmitter 10 for directly applying a composite signal obtained by combining a voltage signal and a current signal of a predetermined frequency to a conductor.
At a desired position for identification in the middle of the longitudinal direction of the cable (hereinafter, referred to as a “desired receiving end”). Receiver 2 to identify whether there is
0. In order to strengthen the electrostatic coupling, the conductor of the target cable 1 to which the transmitter 10 is connected may be either a bundled core wire or a shield layer if there is a shield layer. Assume that the transmitter 10 is connected to the bundled core 2 of the target cable.

The transmitter 10 has a specific frequency determined in advance by a voltage identification method, for example, two frequencies of 390 Hz and 1940 Hz.
Voltage signal oscillation circuits 11 and 12 for oscillating a constant voltage signal of a channel, a current signal supply unit 13 for supplying a constant current of a specific frequency, for example, 40 Hz, which is predetermined by a current identification method, A constant voltage signal and a constant current signal are synthesized and applied directly to the core wire 2 of the target cable 1 via the fixed resistor R1, and the synthesizing circuit 14 is connected to the ground.

The current signal supply unit 13 is connected between the constant frequency oscillating circuit 13a that oscillates a 40 Hz signal and the combining circuit 14 and the core 2, and the , A band pass filter (BPF) 13b for taking in a 40 Hz signal, and a 40 Hz input from the BPF 13b.
A correction circuit 13c for correcting the phase and amplitude of the signal, an adder 13d for adding the 40 Hz signal from the constant frequency oscillation circuit 13a and the correction circuit 13c, and a constant for constantly controlling the current value of the 40 Hz signal to, for example, 5 mA. Current control circuit 13e
And an amplitude limiting circuit 13f for limiting the amplitude of the current-controlled signal and supplying it to the synthesizing circuit 14.

The current signal supply unit 13 configured as described above
Thus, the 40 Hz signal supplied from the constant frequency oscillation circuit 13a is fed back to obtain a difference between the current values, thereby performing constant current control. In addition, 40Hz taken in by BPF13b
The signal is 40 Hz output from the constant frequency oscillation circuit 13a.
Since the signal, the phase, and the amplitude are shifted, the correction is performed by the correction circuit 13c.

At the other end of the target cable 1, an arbitrary core is connected to the ground via a fixed resistor R, and the current of a signal applied to the cable 1 is transmitted through the cable, the fixed resistor and the ground. To form a feedback loop. In the present embodiment, the resistance value of the fixed resistor R is set to 100Ω to prevent the voltage signal applied by the arbitrary core wire and the grounding resistor of the ground terminal from being short-circuited to the ground.

In this case, if the ground resistance of the ground terminal becomes extremely large for some reason, the constant frequency oscillation circuit 13a
Signal increases from the loop resistance proportional to its ground resistance. However, the power supply voltage of the transmitter of the present embodiment uses ± 15 V in order to ensure the safety of the worker. This power supply voltage is commonly used for supplying the voltage signal and the current signal. For this reason, the transmitter 10 controls the output voltage level of the voltage signal to be constant, but the voltage level of the 40 Hz signal fluctuates according to the loop resistance. If the voltage level of the 40 Hz signal is too high, the output voltage level of the composite signal may be saturated. Therefore, in this embodiment, in order to avoid this saturation, a circuit for limiting the voltage level of the 40 Hz signal is provided in the constant current control circuit 13e so that the cable can be identified within a range where the output voltage level of the transmitter 10 is not saturated. Guarantees the supply of signal current.

On the other hand, the receiver 20 is provided, for example, at a desired receiving end in a trough, and includes a voltage identification unit 21 based on a voltage identification system shown in FIG. 2 and a current identification unit 40 based on a current identification system shown in FIG. Consists of When the operator completes the application of the composite signal and the ground connection at the other end of the cable,
With the receiver 20, the cable is identified at the desired receiving end. First, an operator selectively applies the signal electrode 22 of the voltage identification unit 21 to the shield layer of one of the cables in the installation route at the desired receiving end. Then, the signal electrode 2 is input by the input circuit 23.
The voltage signal in the cable is detected by the coupling of the capacitance between the cable 2 and the cable core, and is amplified by the amplifier circuit 24. This voltage signal has the same frequency as that of the voltage signal of the transmitter 10.
The signals are input to the PFs 25 and 26 and are separated and smoothed into two kinds of specific frequency signals of 390 Hz and 1940 Hz, respectively.

Next, the specific frequency signals are converted into DC voltages V1 and V2 by AC / DC converters 27 and 28, respectively, and then compared with threshold values (reference voltage values) set in advance by comparators 29 and 30. Is done. Further, the voltage signal amplified by the amplifier circuit 24 is branched and, for example, the reference frequency 8
The signal is input to a 0 Hz high-pass filter (HPF) 31, separated as a total signal component, converted to a DC voltage VT by an AC / DC converter 32, and then input to a noise level calculator 33. In the noise level calculation unit 33,
By subtracting the signal voltages V1 and V2 converted by the AC / DC converters 27 and 28 from the input total signal voltage VT, a voltage VN = VT-V1-V2 of a noise component is calculated and output to the comparator 29. ing.

In the present embodiment, the method of setting the determination reference for the signal voltage levels of the two DC components by the comparators 29 and 30 is performed as follows. V1> K · V2 + VN V2> VREF where K · V2 + VN, VREF: a threshold value (discrimination reference voltage value) set in each of the comparators 29 and 30, and in this embodiment, VRE
F = fixed at 0.5V VN: Total voltage level of detected noise component (2 channels applied (390Hz, 1940Hz) in detected signal)
K: the set proportional coefficient, K = 0.67 in the present embodiment. Therefore, if both of the two-channel signals are larger than the above-described determination criterion, the output level of the AND circuit 34 Is “1”
The output level is input to the display unit 35 as a detection signal, and a lamp is turned on or a buzzer is sounded to identify that the target cable for which signal detection is being performed is the target cable 1. it can.

Next, the target cable is clamped using the clamper 41 of the current discriminating section 40, and a signal current in the cable is detected. The detected signal current in the cable is taken in from the input circuit 42 via the amplifier 43,
The reference frequency is input to the BPF 44 having a frequency of 40 Hz. Next, in the detected signal current, only a specific frequency component of 40 Hz is extracted as a voltage corresponding to the current level by the BPF 44. The signal voltage at this specific frequency of 40 Hz
The voltage is converted into a DC voltage Vt by an AC / DC converter 45, and is further compared with a determination reference level Vref generated by a determination reference circuit 54 by a comparator 46. The detected signal current is supplied to the LPF 51 having a cut frequency of 120 Hz.
Then, the DC voltage Vt1 corresponding to the total signal current is obtained via the AC / DC converter 52. Then, the noise level calculator 53 calculates the DC voltage Vt,
From Vt1, a voltage level Vn corresponding to the noise component is obtained.
= Vt1-Vt, and the discrimination reference circuit 54 obtains a discrimination reference level Vref based on the voltage level Vn.

The determination reference level Vref is set as follows. Vref = K ・ Vs + J ・ Vn, where Vs: a voltage value corresponding to the current level of the signal applied from the transmitter 10 to the target cable 1 J, K: a set proportional coefficient, and in this embodiment, J = 1.
0, K = 0.8 The comparator 46 compares the DC voltage Vt from the AC / DC converter 45 with the determination reference level Vref from the determination reference circuit 54 under the condition of Vt ≧ Vref.

Therefore, if the DC voltage Vt is equal to or greater than the determination reference Vref, the detection signal from the comparator 46 is displayed on the display unit 48.
To generate a lighting of a lamp or a buzzer, it is possible to identify that the target cable for which signal detection is being performed is the target cable 1. As described above, in the present embodiment, the voltage signal of the specific frequency according to the voltage identification method and the constant current signal of the specific frequency according to the current identification method are combined and simultaneously applied to the same conductor. Operation is not required, and the work time is shortened, and the work efficiency can be improved.

Further, in the present embodiment, the identification of the target cable is double-checked by the voltage identification method and the current identification method, so that the reliability of the identification device can be greatly improved. It should be noted that the method of setting the determination reference of the voltage identification method of the present invention is not limited to the embodiment, and for example, V1> (V2 + VN)
/ K, V2> VREF + VN / K, or V1> K.V2 + VN, V2> VREF + VN.

In this embodiment, the constant current signal supplied to the synthesizing circuit has one kind of frequency. However, the present invention is not limited to this, and a plurality of constant current signals having two or more kinds of frequencies are supplied. It is also possible. In this case, the transmitter has a means for controlling each current value to be constant, and the receiver separates the detected current signal through a BPF using each specific frequency as a reference frequency and checks its level. Identify the cable by Thus, in this embodiment, it is possible to suppress erroneous determination due to the noise of the commercial frequency that is usually most used, and it is possible to improve the reliability of the identification device.

In the present invention, the clamper and the voltage type voltage discriminating unit can be integrally formed. In this case, the connection between the cable and the connector can be omitted, and the number of parts and cost can be reduced. Incidentally, in the constant current control circuit, the signal voltage is controlled in proportion to the loop resistance in order to control the constant current signal to be constant. However, in a portable identification device, it is desirable that the power supply voltage is low. Therefore, it is necessary to restrict the loop resistance. Normally, the identification device has a loop resistance of 800Ω
The following working conditions are defined. In the conventional identification device, a method is used in which a warning is issued when the loop resistance exceeds 800Ω, and the operator immediately takes action to improve the loop resistance upon recognizing the warning.

However, in such a method, since the loop resistance cannot be quantitatively recognized, it is difficult to determine how much improvement is required. Therefore, in the present invention, as shown in the second embodiment of FIG. 4, a loop resistance indicator 15 for measuring and displaying the loop resistance is provided in the transmitter. The same components as those of the transmitter shown in FIG. 1 are denoted by the same reference numerals for convenience of explanation.

An AC / DC converter 16 which branches between the BPF 13b and the correction circuit 13c and takes in a voltage corresponding to a signal current level of 40 Hz;
It comprises a linear correction circuit 17 for linearly correcting the DC voltage level from the AC / DC converter 16 and a liquid crystal display section 18 for displaying a loop resistance value proportional to the DC voltage. The fixed resistance R1 and the core 2 of the target cable 1
Is connected in parallel between the switch S and the resistor R2. When a cable is identified, the switch is turned on, and the resistor R2 is short-circuited by the switch S to generate a 5 mA constant current signal. Flows into the BPF 13b. In the present embodiment, in order to set the measurement range of the loop resistance to 0 to 2000 Ω, for example, the resistance R 2 is fixed to the fixed resistance R 1 of 33 Ω.
Is set to 66Ω.

When the loop resistance is measured, the switch S is turned off by pressing the switch S, and a constant current signal is output to the BPF 13b via the resistors R1 and R2. In this case, the total resistance of the resistors R1 and R2 is 99Ω,
The current value of the constant current signal is constantly controlled to 1/3 of 1.6 mA, and the voltage corresponding to this signal current level is proportional to the change in the loop resistance. Therefore, in the loop resistance indicator 15 of the present embodiment, this signal current component is
b, a DC voltage component corresponding to the signal current level is taken in by the AC / DC converter 16 and the linear correction circuit 17, and the DC voltage component is further displayed on the liquid crystal display unit 18 in correspondence with the loop resistance. . Then, when the measurement of the loop resistance is completed, when the switch S is released and turned on, the transmitter returns to the normal cable identification state.

As described above, in the present embodiment, the transmitter is provided with the loop resistance indicator for measuring the loop resistance, and only when the loop resistance exceeds the limit range, the switch is pressed to measure the actual loop resistance and the liquid crystal display is displayed. In this case, an appropriate ground resistance improvement measure can be selected from the difference between the measured loop resistance value and the limit value. For example, if the limit is 800Ω and the actual loop resistance measured is 900
In the case of Ω, the improvement can be achieved by a simple treatment of spraying water around the ground rod, and the actual loop resistance value is several K.
In the case of Ω, it is possible to judge that fundamental improvement measures such as the length of the earthing rod and the insertion place must be taken.

The object to be identified is a steel wire used as a tension wire for a bridge or the like, in addition to a cable such as an ordinary electric wire, for example, an iron pipe, a plastic pipe with an iron wire wound on a plastic pipe, or a bridge. A long conductive object such as a wire (steel wire) and a metal-reinforced fluid transport pipe can be identified by the present invention.

[0033]

As described above, according to the first aspect of the present invention,
Then, from among a plurality of conductive objects in which a plurality of conductors are respectively included, signals having different frequencies are applied to an object to be identified from a transmitting end side, and a signal component of each frequency is applied to a desired receiving end. In the method of identifying the object to be identified by detecting the object by the side, the first signal of at least one specific frequency supplied with a constant voltage and at least a frequency different from the frequency of the first signal. Since the signal is synthesized with a second signal supplied at one specific frequency and supplied with a constant current, and is directly applied to a desired same conductor of the object to be identified, two identification methods of a voltage identification method and a current identification method are used. Even at the same time, the work efficiency can be improved without the need for signal switching operation or conductor identification.

According to a second aspect of the present invention, the transmission end and the reception end are grounded to form a feedback loop of the second signal, and the loop resistance of the object to be identified is monitored, and the loop resistance is within a predetermined range. In this case, since the current value of the second signal is controlled to a constant value, it is possible to guarantee the supply of a signal current that can identify the cable within a range where the output voltage level on the transmission side is not saturated.

According to the third aspect, a signal having a different frequency is applied from the transmitter to the object to be identified from among the plurality of conductive objects in which the plurality of conductors are respectively included,
In the apparatus for identifying the object to be identified, which detects the signal component of each frequency on the desired receiving end side and identifies the object to be identified, the transmitter includes at least one first frequency of at least one specific frequency.
Constant-voltage supply means for supplying a constant signal to the first signal; constant-current supply means for supplying a second signal having at least one specific frequency different from the frequency of the first signal; And a synthesizing means for synthesizing the second signal and applying the signal directly to the same desired conductor of the object to be identified, so that the transmitting side simultaneously uses two identification methods of the voltage identification method and the current identification method. This eliminates the need for a signal switching operation and eliminates the need for conductor identification at the receiving end, thereby improving work efficiency.

According to a fourth aspect of the present invention, a loop forming means for forming a feedback loop of the second signal by grounding a transmitting end and a receiving end from the transmitter, and the identification means on the transmitting end side from the transmitter. Control means for monitoring the loop resistance of the object and controlling the current value of the second signal to a constant value according to the loop resistance, so that the constant current signal fluctuating due to the loop resistance is Can be controlled to a constant value.

According to a fifth aspect of the present invention, the transmitter detects a voltage corresponding to the second signal supplied with the constant current, and measures and displays a loop resistance value proportional to the voltage value. , The loop resistance can be accurately measured, and an appropriate ground resistance improving measure can be selected based on the measured loop resistance value.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a first embodiment of an identification device using an identification method of an identification target according to the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an example of a voltage identification unit in the receiver shown in FIG.

FIG. 3 is a block diagram showing a schematic configuration of an example of a current identification unit in the receiver shown in FIG.

FIG. 4 is a block diagram showing a schematic configuration of a second embodiment of the transmitter in the identification device according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 object to be identified (target cable) 2 core wire 3 insulating layer 10 transmitter 11, 12 voltage signal oscillation circuit 13 current signal supply unit 14 synthesis circuit 15 loop resistance display 20 receiver 21 voltage identification unit 40 current identification unit

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Kunio Kuroda, Inventor 1-2-2, Ikenota, Taito-ku, Tokyo Japan Denka Kogyo Co., Ltd.

Claims (5)

[Claims] 1. A signal having a different frequency is applied from a transmitting end to an object to be identified from among a plurality of conductive objects in which a plurality of conductors are respectively included, and a signal component of each frequency is applied. In the method for identifying an object to be identified by selectively detecting the object to be identified by a desired receiving end side of the conductive object, a first signal of at least one specific frequency supplied with a constant voltage is provided. At least one different from the frequency of the first signal
A method for identifying an object to be identified, comprising synthesizing a second signal supplied at a specific frequency and supplied with a constant current, and applying the synthesized signal directly to a desired same conductor of the object to be identified. 2. The method according to claim 1, wherein the transmitting end and the receiving end are grounded to form a feedback loop of the second signal, and a loop resistance of the object to be identified is monitored. The method according to claim 1, wherein the current value of the second signal is controlled to a constant value. 3. A signal having a different frequency is applied to an object to be identified from a plurality of conductive objects in which a plurality of conductors are respectively included from a transmitter, and a signal component of each frequency is applied to the object. An identification device for identifying an object to be identified by selectively detecting the object at a desired receiving end side of the conductive object, wherein the transmitter defines a first signal of at least one specific frequency. Constant voltage supply means for supplying a voltage; constant current supply means for supplying a constant current of a second signal having at least one specific frequency different from the frequency of the first signal; and the first and second supplied signals Synthesizing means for synthesizing a signal and directly applying the signal to a desired same conductor of the object to be identified. 4. A loop forming means for forming a feedback loop of the second signal by grounding a transmitting end and a receiving end from the transmitter, and forming a feedback loop of the second signal from a side of the transmitting end from the transmitter. 4. The apparatus according to claim 3, further comprising control means for monitoring a loop resistance and controlling a current value of the second signal to a constant value according to the loop resistance. apparatus. 5. The transmitter includes a loop resistance indicator for detecting a voltage corresponding to the second signal supplied with the constant current and measuring and displaying a loop resistance value proportional to the voltage value. The apparatus for identifying an object to be identified according to claim 4, characterized in that: