JP2005114561A - Cable search device and cable search method - Google Patents

Abstract

A cable search device and a cable search method capable of searching for a cable with high accuracy from an arbitrary point of the cable.
A transmitter 10 that outputs a digital signal current, a current transformer 20 that induces a current corresponding to the digital signal current from the transmitter 10 in a cable 40 to be searched by electromagnetic induction, and a current transformer 20 and a receiver 30 that detects a magnetic field generated by a current induced in the cable 40 by the power supply 20.
[Selection] Figure 1

Description

  The present invention relates to a cable search device and a cable search method, and more particularly to a cable search device and a cable search method for searching for a terminal from the middle of a cable.

  For example, a large number of cables housed in racks and ducts are laid in the factory and on the track. Such cables will need to be replaced or removed over time. In such a case, the cable search device is used to search where each cable is connected.

  A conventional cable search device of this type includes a transmitter and a receiver. The transmitter is used, for example, to inject an analog signal current into a cable from a distribution board on the power source side or a load connection terminal on the load side.

The receiver detects a magnetic field generated by electromagnetic induction by the signal current injected into the cable. The cable search is performed by following the cable laying path while checking whether the receiver can detect the magnetic field generated by the cable into which the signal current is injected by the transmitter (see, for example, Patent Document 1).
JP 2002-122627 A

  However, the transmitter used in the conventional cable search device is an electromagnetic induction type that detects the magnetic field generated by the analog signal current injected into the cable. It is easily affected by external noise generated by the connected devices, and the cable search accuracy is low.

  Also, when re-installing or removing a cable, each cable is effective by opening a rack or duct at a certain point (for example, the middle point of the cable) and checking the connection destination of each cable accommodated there. You may want to find out if there is. However, in the conventional cable search apparatus, since it is necessary to inject the signal current flowing through the cable from the terminal, such a case cannot be dealt with.

  Then, the subject of this invention is providing the cable search apparatus and cable search method which can perform a cable search with high precision from the arbitrary points of a cable.

  In order to solve the above problems, the present invention has the following configuration. According to a first aspect of the present invention, there is provided a cable search device including a transmitter that outputs a digital signal current, and a current transformer that induces a current corresponding to the digital signal current from the transmitter to a cable to be searched by electromagnetic induction. And a receiver for detecting a magnetic field generated by a current induced in the cable by a current transformer.

  According to the cable search device of the present invention, the current is induced in the cable by electromagnetic induction using the current transformer, and the presence or absence of the cable is detected by detecting the magnetic field generated based on the induced current. Since the detection and the search are performed, the cable search can be started from an arbitrary position of the cable by installing the current transformer at an arbitrary position.

  In addition, since the current induced in the cable is a current corresponding to the digital signal current, the receiver can identify the presence or absence of the cable by digital signal processing. As a result, it is difficult to be affected by external noise, and a cable search with high accuracy is possible.

  In the cable search device according to a second aspect of the present invention, the current transformer is configured in an annular shape that can be divided in the radial direction, and is arranged so as to surround the cable.

  According to the cable search device of the second aspect of the present invention, it is easy to attach the current transformer to the cable, and the cable search work can be performed efficiently.

  In the cable search device according to the invention of claim 3, the current transformer is arranged between both ends of the cable.

  According to the cable search device of the invention of claim 3, the rack or duct is opened at a point other than both ends of the cable, for example, at an intermediate point of the cable, and the connection destination of each cable accommodated therein can be checked. It becomes possible.

  According to a fourth aspect of the present invention, there is provided a cable search method that generates a digital signal current, induces a current corresponding to the generated digital signal current in a cable to be searched by electromagnetic induction, and is induced in the cable. The magnetic field generated based on the current is detected, and the cable is searched.

  According to the cable search method of the invention of claim 4, the cable is induced by electromagnetic induction, and the presence or absence of the cable is detected by detecting the magnetic field generated based on the induced current, and the search is performed. Since the current is induced at an arbitrary position of the cable, the search can be started from an arbitrary position of the cable. Further, since the current induced in the cable is a current corresponding to the digital signal current, the presence or absence of the cable can be identified by digital signal processing. As a result, it is difficult to be affected by external noise, and a cable search with high accuracy is possible.

  The cable search method according to the invention of claim 5 is characterized in that the induction of the current according to the digital signal current is performed between both ends of the cable.

  According to the cable search method according to the invention of claim 5, the rack or duct is opened at a point other than both ends of the cable, for example, at the middle point of the cable, and the connection destination of each cable accommodated therein is examined. It becomes possible.

  ADVANTAGE OF THE INVENTION According to this invention, the cable search apparatus and cable search method which can perform a cable search with high precision from the arbitrary points of a cable can be provided.

  Specifically, according to the present invention, the presence or absence of the cable is detected by inducing a current in the cable by electromagnetic induction at an arbitrary position of the cable and detecting a magnetic field generated based on the induced current. Since the search is performed, the search can be started from an arbitrary position of the cable. Further, since the current induced in the cable is a current corresponding to the digital signal current, the presence of the cable can be identified by digital signal processing. As a result, it is difficult to be affected by external noise, and a cable search with high accuracy is possible.

  Hereinafter, a cable search device and a cable search method according to embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a cable search apparatus according to an embodiment of the present invention. The cable search apparatus includes a transmitter 10, a current transformer 20, and a receiver 30.

  The transmitter 10 generates and outputs a digital signal current. More specifically, as shown in FIG. 3, the transmitter 10 is a digital signal by superimposing a predetermined signal wave on a carrier frequency of 33.3 kHz when the switch 13 is operated. A microprocessor 15 that generates current and a transmission output unit 17 that transmits and outputs a digital signal current generated by the microprocessor 15 are provided.

  The transmitter 10 includes an outlet 11 into which the plug 21 of the current transformer 20 is inserted. The digital signal current generated by the transmitter 10 is sent to the current transformer 20 via the outlet 11.

  The current transformer 20 is configured in a ring shape that can be divided in the radial direction, and a cable 40 to be searched is inserted into a hollow portion of the ring. Details of the current transformer 20 will be described later.

  The receiver 30 includes an antenna 31, a switch 33, a microprocessor 35, and a receiving unit 37 shown in FIG. The antenna 31 detects a magnetic field generated by the current flowing through the cable 40 and sends it to the microprocessor 35 via the receiving unit 37.

  Microprocessor 35 processes the signal from antenna 31 to identify the strongest signal. The display unit 50 displays the identification result from the microprocessor 35. The voice output unit 60 outputs the identification result from the microprocessor 35 by voice.

  The microprocessor 35 holds the peak of the received signal and identifies only the strongest signal based on this peak, and the reception sensitivity switching unit that switches the reception sensitivity between the high range and the low range according to the strength of the signal. 353.

  The reception sensitivity switching unit 353 has a low range switch and a high range switch (not shown). The low range switch is used when the antenna 31 of the receiver 30 is directly applied to the cable 40, and the high range switch is used in other cases.

  FIG. 2 is a plan view showing a detailed structure of the current transformer 20. The current transformer 20 includes a C-shaped first ferrite core 22 and a C-shaped second ferrite core 23.

  A coil 24 is wound around the center portion of the C-shaped first ferrite core 22, and the contraction tube 25 covered on the coil 24 contracts, whereby the coil 24 is fixed to the first ferrite core 22. Yes.

  A digital signal current is supplied to the coil 24 from the transmitter 10 via the plug 21. Further, bands 26a and 26b made of SUS material are attached to the two open ends of the first ferrite core 22, and parts of the snap locks 27a and 27b made of SUS material are attached to the bands 26a and 26b, respectively. ing.

  Further, a shrink tube 28 is put on the center of the C-shaped second ferrite core 23, and bands 29a and 29b made of SUS material are attached to the two open ends, and a snap lock is attached to the bands 29a and 29b. Each other part of 27a, 27b is attached, respectively.

  In addition, marks M1 and M2 are added to one open end of each of the first ferrite core 22 and the second ferrite core 23 in order to display the polarity.

  Next, an operation in the case of performing a cable search using the cable search apparatus according to the embodiment of the present invention configured as described above will be described.

  When searching for a cable from an arbitrary position, first, the user opens the snap locks 27 a and 27 b of the current transformer 20, so that the C-shaped first ferrite core 22 and the second ferrite core 23 2 are opened. Divide into two.

  The divided C-shaped first ferrite core 22 and the second ferrite core 23 sandwich the cable 40 to be searched among the plurality of cables so that the marks M1 and M2 are on the same side. Then, the snap locks 27a and 27b are stopped. Thereby, as shown in FIG. 2, the state where the cable 40 was inserted in the hollow part of the annular core is formed.

  Next, the plug 21 of the current transformer 20 is inserted into the outlet 11 of the transmitter 10. After that, when the transmitter 10 is turned on and the switch 11 is pressed, the microprocessor 15 generates a digital signal current by superimposing a predetermined signal wave on the carrier frequency of 33.3 kHz, and the transmission output unit 17 Transmits a digital signal current generated by the microprocessor 15. That is, the transmitter 10 generates a digital signal current and supplies it to the current transformer 20.

  In the current transformer 20, when a digital signal current supplied from the transmitter 10 flows through the coil 24, a magnetic flux is generated in an annular magnetic path formed by the first ferrite core 22 and the second ferrite core 23.

  By electromagnetic induction based on the generated magnetic flux, a current is induced in the cable 40 arranged in the hollow portion of the current transformer 20, and a current corresponding to the digital signal current supplied from the transmitter 10 flows in the cable 40. . A magnetic field is generated around the cable 40 by the current flowing through the cable 40. The distribution of the generated magnetic field is indicated by a dotted line in FIG.

  In this state, the user brings the antenna 31 of the receiver 30 closer to the plurality of cables at a position away from the position where the current transformer 20 is installed (for example, near the end of the cable). As a result, the antenna 31 detects a magnetic field generated by the current flowing in the cable 40 and sends it to the microprocessor 35.

  In the microprocessor 35, the peak hold unit 351 holds the peak of the signal from the antenna 31. For example, when there are a cable 40 and two other cables and a transmitter is installed in the cable 40, the signal level from the cable 40 is higher than the signal level from the other cables A and B. For this reason, the peak hold unit 351 holds the signal from the cable 40 as a peak. That is, the strongest signal is identified by this peak, and a strong signal sound is output to the audio output unit 60 and blinked on the display unit 50 such as an LED. Since signals from the other cables A and B are smaller than signals from the cable 40, they are not blinked on the display unit 50. Therefore, it can be determined that the cable whose blinking is recognized on the display unit 50 is the cable 40 in which the current transformer 20 is installed.

  Further, the reception sensitivity switching unit 353 switches the reception sensitivity between the high range and the low range in accordance with the strength of the signal. Normally, in a transmitter that holds a search range of more than 6 km, in cable identification over a short distance (0 to about 20 m), the search is performed in a low reception sensitivity state with a low range, thereby facilitating the work.

  As described above, according to the cable search device according to the embodiment, a current is induced in the cable 40 by electromagnetic induction using the current transformer 20, and a magnetic field generated based on the induced current is detected by the receiver 30. Thus, the presence / absence of the cable 40 is displayed, so that a rack or duct is opened at an arbitrary point other than both ends of the cable 40, for example, at an intermediate point of the cable 40, and each cable 40 accommodated therein You can check the connection destination.

  Further, the transmitter 10 generates a digital signal current and supplies the digital signal current to the current transformer 20, and the current transformer 20 induces a current in the cable 40 in accordance with the digital signal current. The presence of the cable can be identified by processing. As a result, it is difficult to be affected by noise transmitted as an analog signal from the outside, and the cable search can be performed with high accuracy.

The inventors conducted a cable search test using a cable search apparatus as shown in FIG. Tests were performed on two types of cables: (1) 6 kV CV 8 mm ² and (2) VV 3c × 2.6 mm. The CV cable has a shield, and the VV cable has no shield. Each cable length was 30 m. As a test result, a signal from the current transformer 20 was induced in both the conductor and shield of the electric wire, and the target cable could be searched regardless of the presence or absence of the shield.

It is a block diagram which shows the structure of the cable search apparatus which concerns on embodiment of this invention. It is a top view which shows the structure of the current transformer used with the cable search apparatus which concerns on embodiment of this invention. It is a block diagram of the configuration of a transmitter provided in the cable search device. It is a block diagram of the configuration of a receiver provided in the cable search device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Transmitter 11 Outlet 13, 33 Switch 15, 35 Microprocessor 17 Transmission output part 20 Current transformer 21 Plug 22 1st ferrite core 23 2nd ferrite core 24 Coil 25, 28 Contraction tube 26a, 26b, 29a, 29b Band 27a, 27b Click lock 30 Receiver 31 Antenna 37 Receiver 40 Cable 50 Display unit 60 Audio output unit 351 Peak hold unit 353 Reception sensitivity switching unit

Claims (5)

A transmitter that outputs a digital signal current;
A current transformer for inducing a current corresponding to a digital signal current from the transmitter to a cable to be searched by electromagnetic induction; and
A receiver for detecting a magnetic field generated based on a current induced in the cable by the current transformer;
A cable search device comprising:   The cable search device according to claim 1, wherein the current transformer is configured in an annular shape that can be divided in a radial direction, and is arranged so as to surround the cable.   The cable search device according to claim 1, wherein the current transformer is disposed between both terminals of the cable. Generate digital signal current,
A current corresponding to the generated digital signal current is induced in the cable to be searched by electromagnetic induction,
A cable search method, wherein a magnetic field generated based on a current induced in the cable is detected and the cable is searched. The cable search method according to claim 4, wherein the induction of the current according to the digital signal current is performed between both ends of the cable.

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