JPH11133091A - Cable anomaly detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect anomalies in a cable simply by inputting a high-frequency signal to a cable to be inspected and determining on the basis of its reflection signal. SOLUTION: At the time of inspection, a high-frequency signal from a high-frequency generator 10 is inputted to a directional converter 8 → a change-over switch 7 → lines 7 → a cable connection changing device 4 → signal transmitting cables 5. On the other hand, a high-frequency reflection signal from the signal transmitting cables 5 and a terminal block 6 is inputted to the cable connection changing device 4 → the lines 7 → the change-over switch 7 →the directional converter 8 → a determining device 9. By calculating a reflection coefficient on the basis of the reflection signal, the determining device 9 can simply determines the presence or absence of phenomena such as a breakage, a short circuit, an insulation failure in each signal transmitting cable 5, grasp the situations, and determine anomalies in each signal transmitting cable 5. In addition, by placing the cable connection changing device 4, it is possible for a single workman to perform inspection by remote control even on long signal transmitting cables.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable abnormality detecting device for detecting an abnormality in a signal transmission cable.

[0002]

2. Description of the Related Art FIGS. 5 and 6 are diagrams for explaining a conventional signal cable abnormality detecting method. As shown in FIG. 5, when detecting disconnection, insulation or the like of the signal transmission cable 5 connected to the measuring instrument 2 and the terminal block 6, conventionally, the signal transmission cable 5 is first removed from the measuring instrument 2 and the terminal block 6. Then, as shown in FIGS. 6A and 6B, a tester or a resistance measuring device 15 is provided at both ends of the signal cable core wire 51.
The disconnection was inspected by measuring the resistance of the core wire 51 at 2,153. Similarly, the core wire 51 and the shield wire 5
The insulation test was performed by measuring the resistance between the two.

FIG. 7 shows a TDR apparatus (time domain reflectometer:
It is a figure for explaining a signal cable abnormality detection method by time-domain reflectometer). Conventionally, as shown in FIG. 7, a method of applying a rectangular pulse voltage from the TDR device 16 and observing a reflected voltage waveform in the middle of the signal transmission cable 5 (hereinafter, referred to as a TDR method) is used.

[0004]

However, the method described above,
For example, in the case of an inspection method using a tester or the like, since it takes time to remove the cable, it is difficult for one operator to perform the inspection when the cable installation distance is long.
Further, in the TDR method, the reflected voltage of the same level is returned to the measuring end from the two connection points of the cable with respect to the pulse voltage applied to the test cable, so that the reflected waveform becomes complicated and it is difficult to clarify.

For example, as shown in FIG. 8A, when the signal transmission cable 5 is normal, the terminal block 17 and the terminal block 1 are connected.
8 gives the reflected voltage. Since nothing is connected after the terminal block 18, the reflected voltage remains output.
If a disconnection occurs near the terminal block 18, whether the reflected voltage is caused by the disconnection or if the terminal block 18
It is difficult to distinguish whether the signal is from a computer.

As shown in FIG. 8 (b), the voltage reflected from the part of the signal transmission cable 5 which is about to be disconnected, the part where insulation is reduced, the terminal blocks 17, 18 and the like are measured. Therefore, the entire reflected voltage waveform becomes complicated, and it becomes difficult to clarify the waveform. SUMMARY OF THE INVENTION An object of the present invention is to provide a cable abnormality detecting device for easily detecting a cable abnormality.

[0007]

Means for Solving the Problems To solve the above problems and achieve the object, a cable abnormality detecting device of the present invention is configured as follows. (1) The cable abnormality detection device of the present invention is configured to input a high-frequency signal to a cable to be inspected and detect an abnormality of the cable to be inspected based on a reflected signal. (2) The cable abnormality detection device of the present invention is the device described in (1) above, and further includes means for switching a connection state of the cable under test between a normal state and a test state.

[0008]

FIG. 1 is a block diagram showing a configuration of a measurement system to which a cable abnormality detecting device according to an embodiment of the present invention is applied. In FIG. 1, a plurality of detectors 1 are connected to a cable connection switching device 4 via measuring devices 2 respectively. The cable connection changer 4 is connected to the terminal block 6 via three signal transmission cables 5, is connected to the connection changeover controller 3, and is connected to the changeover switch 7 via three lines 71. Have been. The changeover switch 7 is connected to the determination device 9 and the high frequency generator 10 via the directional converter 8.

In FIG. 1, a high-frequency signal oscillated from a high-frequency generator 10 at the time of an abnormality inspection is transmitted to a signal transmission cable 5 by a cable connection switching device 4 via a directional converter 8, a changeover switch 7 and a line 71. Is entered. On the other hand, the high-frequency reflection signals from the signal transmission cable 5 and the terminal block 6 are input to the determination device 9 via the cable connection changer 4, the line 71, the changeover switch 7, and the directional converter 8.

FIG. 2 is a perspective view showing the structure of the cable connection switching device 4. In the cable connection switching device 4, the rotation axis of the motor 13 installed on the slide table 12 is
A terminal mounting plate 14 is mounted. Normally, three terminals 14 on one plate 141 of the terminal mounting plate 14
11, the corresponding signal transmission cables 5 are connected one by one. The signal terminals from the corresponding measuring instruments 2 are connected one by one to the three terminals 1421 of the other plate 142 of the terminal mounting plate 14.

The terminal mounting plate 14 is rotated in the direction from a to b or from b to a by the driving of the motor 13, and the slide table 12 is moved in the direction from c to d or from d to c by a drive unit (not shown). . The terminal connection is switched by the cable connection switching device 4 having such a configuration between a normal signal transmission and a cable inspection as described later.

As shown in FIG. 1, the cable abnormality detecting device includes a cable connection switching device 4 provided in the middle of a normal signal transmission line. The connection between a signal line from each measuring instrument 2 and a line 71 for transmitting a high-frequency signal to the signal transmission cable 5 is switched. When the inspection of the signal transmission cable 5 is performed, the slide table 12 shown in FIG. 2 is moved in the direction of c by the signal from the connection switching controller 3 so that the signal transmission cable 5 and the signal line from the measuring instrument 2 are connected. Separate from the terminals of the plates 141 and 142, respectively.

Next, the terminal mounting plate 14 is rotated in the direction from a to b, and then the slide table 12 is moved in the direction d. Thereby, the three terminals 142 of the plate 142
1, one signal transmission cable 5 is connected to each. Also, one line 71 is connected to each of the three terminals 1411 of the plate 141. That is, each signal transmission cable 5 and each line 71 are connected via the cable connection switch 4 so as to form a pair one by one. This makes it possible to input a high-frequency signal from the high-frequency generator 10 to each signal transmission cable 5.

FIG. 3 is a flowchart showing the operation procedure of the cable abnormality detecting device. In a state where the normal measurement is being performed, when a cable inspection instruction is given from an input unit (not shown) in step S1, step S1 is performed.
At 2, the connection switching controller 3 generates a signal to the cable connection switcher 4. Then, in step S3, the cable connection switching device 4 makes the slide table 12 operable,
Move from d to c. As a result, the connected signal line from the measuring instrument 2 and the signal transmission cable 5 are disconnected.

Next, in step S4, the cable connection switch 4 drives the motor 13 to rotate the terminal mounting plate 14 in the direction from a to b. Then, in step S5, the cable connection switching device 4 moves the slide table 12 in the direction from c to d. Thereby, each line 71 and each signal transmission cable 5 are connected as described above.

Subsequently, in step S6, the high-frequency generator 10 generates a high-frequency signal under the control of a control unit (not shown).
This high-frequency signal is supplied to a directional converter 8, a changeover switch 7,
The signal is transmitted to one corresponding signal transmission cable 5 via one line 71 and the cable connection switching device 4. Next, in step S7, the judging device 9 sends the reflection signal from the one signal transmission cable 5 to the cable connection switch 4, the one line 71, the changeover switch 7, and the directional converter 8
To enter through. Then, the judging device 9 detects an abnormality of the one signal transmission cable 5 from the input reflected signal,
In step S8, the location where the abnormality has occurred is determined.
Next, in step S9, the changeover switch 7 sets the next line 1
Change the switch to 7.

In step S10, the above-described steps S7 and S7 are repeated until the inspection of all the signal transmission cables 5 is completed.
To S9. When the inspection of all the signal transmission cables 5 is completed in Step S10, Step S11
Then, the control unit controls the high frequency power of the high frequency generator 10 to O
Set to FF. Then, in step S12, the cable connection switching device 4 moves the slide table 12 from d to c,
In step S13, the motor 13 is turned on, and the terminal mounting plate 14 is rotated from b to a. In step S14, the slide table 12 is moved from c to d. This returns to the normal connection state described above. After that, the processes after step S1 are performed again. If no cable inspection instruction is given in step S1, step S15
Then, continue the normal measurement.

FIGS. 4A to 4E are diagrams showing reflected signals input to the determination device 9. FIG. When a high-frequency pulse is applied as shown in FIG. 4A, the signals from the changeover switch 7, the cable connection switch 4 and the terminal block 6 are normally output as shown in FIG. ´4
', 6'. But signal transmission cable 5
At the time of disconnection, 7 ', 4' as shown in FIG.
And a signal from the disconnected portion is detected. Further, when the signal transmission cable 5 is short-circuited, a signal is detected from a short-circuited point of 7 ', 4' as shown in FIG. Also, when the insulation of the signal transmission cable 5 is poor, FIG.
As shown in (e), signals from 7 ', 4', and 6 'and insulation failure locations are detected.

As described above, by inputting the high-frequency signal to each signal transmission cable 5 and observing the reflected waveform,
Since a reflection signal as shown in FIG. 4 is obtained, the determination device 9
By calculating the reflection coefficient on the basis of the reflection signal, the presence or absence of the phenomenon such as disconnection, short circuit, insulation failure and the like of each signal transmission cable 5 can be easily grasped, and the abnormality of each signal transmission cable 5 is determined. be able to. Also, by installing the cable connection switching device 4 as described above,
Even a long signal transmission cable can be inspected by one operator by remote control.

It should be noted that the present invention is not limited to only the above-described embodiment, and can be implemented with appropriate modifications without departing from the scope of the invention. (Summary of Embodiment) The configuration, operation and effect shown in the embodiment are summarized as follows. [1] The cable abnormality detection device described in the embodiment
A high-frequency signal is input to the cable under test (5), and an abnormality of the cable under test (5) is detected based on the reflected signal.

Therefore, according to the cable abnormality detecting device, the location where the abnormality has occurred in the cable (5) is
It can be grasped simply and quickly based on the reflection signal of the high frequency signal. [2] The cable abnormality detecting device according to the embodiment is the device according to the above [1], and means (4) for switching a connection state of the cable under test (5) between a normal state and a test state. Is provided.

Therefore, according to the cable abnormality detecting device, even when the distance of the cable (5) is long, it is possible to easily perform the inspection by remote operation by one operator, and the work efficiency is improved, Inspection time can be reduced.

[0023]

According to the cable abnormality detecting device of the present invention, the location where the abnormality has occurred in the cable can be easily and quickly grasped based on the reflection signal of the high frequency signal. ADVANTAGE OF THE INVENTION According to the cable abnormality detection apparatus of this invention, even when the distance of a cable is long, it becomes possible to perform an inspection easily by remote control by one worker, and work efficiency improves and inspection time can be shortened. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a measurement system to which a cable abnormality detection device according to an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a configuration of a cable connection switching device according to the embodiment of the present invention.

FIG. 3 is a flowchart showing an operation procedure of the cable abnormality detection device according to the embodiment of the present invention.

FIG. 4 is a diagram showing a reflected signal according to the embodiment of the present invention.

FIG. 5 is a diagram for explaining a signal cable abnormality detection method according to a conventional example.

FIG. 6 is a diagram for explaining a signal cable abnormality detection method according to a conventional example.

FIG. 7 is a diagram for explaining a signal cable abnormality detection method by a TDR device according to a conventional example.

FIG. 8 is a diagram showing a reflection signal according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Detector 2 ... Measuring instrument 3 ... Connection switching controller 4 ... Cable connection switching machine 5 ... Signal transmission cable 6 ... Terminal block 7 ... Changeover switch 8 ... Directional converter 9 ... Judgment device 10 ... High frequency generator 11 ... Pedestal 12 ... Slide table 13 ... Motor 14 ... Terminal mounting plate

Claims (2)

[Claims] 1. A cable abnormality detecting device which inputs a high-frequency signal to a cable to be inspected and detects an abnormality of the cable to be inspected based on a reflected signal thereof. 2. The cable abnormality detecting device according to claim 1, further comprising means for switching a connection state between the normal state and the inspection state of the cable to be inspected.