JPH0622424A - Identifying method for object to be identified - Google Patents

Abstract

(57) [Summary] [Purpose] Accurately identify a predetermined object to be identified from among multiple objects to be identified without being affected by the capacitance between conductive objects to be identified such as cables. . [Structure] A signal voltage V _S from an oscillating section 10 is applied to a target cable A, and a detecting section 2 by an electrostatic coupling method
In the method of identifying an object to be identified in which the detection voltage is detected from the target cable A by 0 and the target cable A is detected, the target cable A is disconnected from the ground, and the oscillator 10 and the cables B to D are not used. Each of the cables is grounded and the sensitivity of the detection unit 20 is adjusted according to the level of the detection voltage detected by the detection unit 20 so that the signal voltage is not detected from a cable other than the target cable A. The target cable A is detected without misjudgment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of identifying a conductive object to be identified, for example, an object to be identified for identifying a predetermined cable from a plurality of cables accommodated in a railway trough.

[0002]

2. Description of the Related Art Normally, a railway trough accommodates dozens of cables, and some of these cables cannot be used due to their longevity or failure due to aging. Sometimes In this state,
When laying a new cable, it is often impossible to lay a new cable unless the unnecessary cable is removed. However, in such a case, it is extremely difficult to remove unnecessary cables because it is not known which cables are needed and which cables are not needed, and accidentally accidentally removing used cables. There has also been a need for a device that can open a trough lid at any location to search for a particular cable.

Conventionally, in response to the above demand, a signal voltage is directly applied to the core wire of the cable to be removed, and the signal voltage is detected through an electrode capacitively coupled to the cable to identify the cable. There was a way.

[0004]

However, in an actual trough, there are dozens of cables, which are usually to be identified, in a very random manner, and electrostatic coupling is present between these cables. In some cases, the capacitance between adjacent cables may be larger than the capacitance existing between the signal electrode of the detection unit and a predetermined target cable. In such a case, due to the influence of the electrostatic capacitance between the cables, the applied signal is also detected from the cable adjacent to the target cable, which causes a phenomenon in which the target cable cannot be detected from the identification target cable. There was a problem.

The present invention has been made in view of the above problems, and provides a cable identification method capable of accurately identifying a target cable from a plurality of cables without being affected by the capacitance between the cables. The purpose is to provide.

[0006]

In order to achieve the above object, according to the present invention, a signal voltage from an oscillator is directly applied to a predetermined object to be identified from among a plurality of electrically conductive objects to be identified. In the method of identifying an object to be identified, the signal voltage is detected from the object to be identified by a detection unit by an electrostatic coupling method, and the object to be identified is detected. Is not grounded, and the unused object to be identified is grounded from the oscillator and the object to be identified, and a sensitivity adjusting means is provided in the detector to detect the detected signal voltage. There is provided a cable identification method for detecting the predetermined object to be identified by adjusting the sensitivity of the sensitivity adjusting unit according to the level.

[0007]

Function: A signal voltage is applied from a grounded oscillating unit to a target cable, which is a predetermined object to be identified that is not grounded, and the gain of the signal detected by a non-contact detection unit of capacitive coupling. Adjustment is performed to detect the signal voltage. Therefore, the signal voltage is not detected from cables other than the target cable, and the target cable can be accurately identified without making an erroneous determination.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to the drawings of FIGS.
Explain. 1 to 3 illustrate the principle of the present invention.
For this reason, the three types of typical situational principle diagrams and their
Equivalent circuit, and these figures show
The effect of capacity is analyzed theoretically. In these figures, A
~ D is a cable to be identified, the cable A is the eye
It is a standard cable. In addition, in (a) of FIG. 1 to FIG.
The cross sections of cables A to D are shown respectively, and
Bulls A to D are core wires A ₁~ D₁And shield layer A₂~ D₂
It consists of and. These cables A to D are long
In parallel with each other.
It In each of the above figures, the connection between adjacent cables is
For the sake of explanation, all capacities are the same to simplify the problem.
Same C_TAnd its impedance is Z.

First, the detection of the target cable A in FIG.
A case will be described. In Figure 1 (a), earth ground
From the oscillated portion 10 to the core wire A of the target cable A₁Direct to
In addition, a specific voltage signal (for example, the signal voltage V_S) Is applied,
Core wire A of cable A₁Coupling between the electrode and the signal electrode 21
Capacity C_A(See FIG. 1 (b))
Detect a specific voltage signal. Where the coupling capacitance C_AInn of
Pedestal Z_CA, Input Impeder of the detection circuit described later
Z_IN, The detection voltage of the specific voltage signal is V _INage,
Actually V_INZ to prevent saturation of_IN≪Z_CAThen,
From the equivalent circuit of Fig. 1 (b), the detected voltage V_INAnd ask for V_IN= V_S・ Z_IN/ (Z_IN+ Z_CA) = V_S・ Z_IN/ Z_CA … (1). In addition, the detection unit 20 includes in the detected signal.
Signal voltage of three types of frequencies (hereinafter, "frequency
Number signal ". ) Level is target cable A
Discrimination, in other words, detection voltage V_INTarget by the size of
Determine if it is cable A.

Here, the signal voltage V_STo be large enough
To achieve this, one important constraint is the target cable
A core wire A₁, Shield layer A₂Or all of the exterior is ground
Must not be grounded. Because the signal
Pressure V_SIf the conductor part that applies
Influence of the internal impedance of the vibration unit 10 (usually about 50Ω)
Then, the signal potential level of cable A becomes close to zero.
As a result, the detection voltage V _INIs also near zero, the target cave
This is because it becomes impossible to identify the rule A.

Next, the case of discriminating between the target cable A and the cable B having a large coupling capacity in FIG. 2 will be described. In this case, as shown in Fig. 2 (a), the cable B is
It is adjacent to the target cable A, grounded, and its impedance is Z _B. In this equivalent circuit shown in FIG. 2B, the electrostatic coupling capacitance between the core wire B ₁ of the cable B and the signal electrode 21 is C _B , and its impedance is Z _CB.
And When the detection voltage V _IN in this case is calculated, V _IN = [Z _B · Z _CB / {Z (Z _B + Z _CB ) + Z _B · Z _CB }] · [V _S · Z _IN / Z _CB ] ... (2 ). The impedances Z and Z _CB cannot be artificially changed, depending on the arrangement of the cables in the trough. Therefore, the value of the detection voltage V _IN greatly changes depending on the impedance Z _B. In addition, since the cable in use always uses a certain AC power source and is grounded, the impedance Z _B is at most on the order of 10 KΩ. Impedance Z, Z _CB is usually 1
Since it is on the order of 0 MΩ, Z _B << Z _CB and Z _B
<< Z is clear. The detection voltage V _IN obtained by the equation (2) can be simplified as V _IN = (Z _B / Z) · (V _S · Z _IN / Z _CB ) ... (3). Here, V _IN of V _IN «formula of formula (3) (2)
Therefore, even if the signal electrode 21 contacts the cable B, the detection unit 20 does not generate the detection voltage V _IN from the cable B,
The target cable A and the cable B can be reliably distinguished.

Here, in order to make the detection voltage V _IN of cables other than the target cable sufficiently small, it is necessary to surely ground the oscillator 10 as one of the important limiting conditions. Because the impedance Z _B is the oscillation unit 10
Impedance between earth and ground (this impedance is
It can be said that the value of 1 KΩ is sufficiently small. ) Is included, and if the oscillator 10 is not grounded,
When the signal electrode 21 contacts all cables,
This is because the detection voltage V _IN is generated for each.

The reason why the detection voltage V _IN is generated in each case is that in the above case, the impedance Z _B becomes close to infinity and the cables in the trough become very long, so that the coupling capacitance between the cables becomes large. Is sufficiently larger than the electrostatic coupling capacitance C _B , and as a result, Z _B >> Z, Z _B >>
Z _CB, since the Z«Z _CB, the detected voltage V _IN of the formula (2) _{is, V IN = V S · Z} IN / (Z CB + Z IN) = V S · Z IN / Z CB ... (4) Can be simplified. V _IN of the formula (4) is substantially equal to the V _IN of the formula (1). Therefore, the target cable cannot be identified.

Next, when the cable B is not in use,
The determination of the target cable A will be described. In this case, when there are two cables A and B in the trough, the impedance Z _B shown in FIG. 2 is close to infinity, which is the same as the situation expressed by the equation (4).
It is difficult to reliably identify B and B. Therefore, if the conductor of the cable B is grounded, the impedance Z _B
Becomes close to zero, the detection voltage V _IN from the cable B also becomes close to zero, and the target cable A and the cable B can be easily identified. Therefore, also in this case, in order to sufficiently reduce the detection voltage V _IN of the unused cable B other than the target cable, grounding the cable B is one important condition.

However, in a real situation, it is more complicated and there are dozens of cables in the trough, the majority of which are in use. It is also difficult to easily ground all unused cables. Therefore, in the present invention, the situation of the embodiment as shown in FIG. 3 will be examined. In this embodiment, there are unused cables A and B in the trough, both cables are arranged next to each other and have a large coupling capacitance with each other. The cables C and D existing around the cables A and B are all in use. Under such circumstances, each cable C, D
The impedances to the ground of the cables are Z _C and Z _D , respectively, and the coupling capacitances between the cables B and C and the cables B and D are C _{T as} described above, and the impedance thereof is Z.

In this case, in this equivalent circuit shown in FIG. 3B, the cables C and D in use are Z _C << Z, Z _D <<.
Z, and the impedances Z _C and Z _D can be ignored, so the voltage V _{B of the} cable _B and the signal voltage V _S
And the relationship between the detection voltage V _IN and the signal voltage V _S are: V _B = V _S · Z _CB / (Z + 3Z _CB ) ... (5) V _IN = V _S · {Z _CB / (Z + 3Z _CB )} · Z _IN / Z _CB = V _S · Z _IN / (Z + 3Z _CB ) ... (6), and the level of the detection voltage V _IN from the cable B is less than 1/3 of the level of the detection voltage V _IN from the target cable. It was found from equations (1) and (6) that there is no such thing. Therefore, even if the cable B not in use is not grounded, the level of the detection signal V _IN from the cable B is 1 / the level of the detection signal V _IN from the target cable due to the influence of the surrounding cable in use. It is 3 or less, and in such a case, the target cable A can be identified by appropriately adjusting the sensitivity of the detection unit 20.

Based on the above verification, in the present invention, when the target cable is identified by using, for example, the electrostatic coupling type cable identification device shown in FIG. . (1) Disconnect the cable to be removed from the connection terminal or the ground. (2) If an unused cable exists in the oscillator circuit and the trough to be worked, the shield layer of the above cable (or the core of each bundled cable if there is no shield layer) is grounded. To do.

(3) However, if there are special circumstances, the target cable can be identified by adjusting the sensitivity of the detection unit, which will be described later, without grounding to ground. As described above, FIG. 4 is a block diagram showing the configuration of the identification device using the cable identification method according to the present invention. In addition, in FIG.
For the convenience of description, the same components as those shown in FIGS. 1 to 3 are designated by the same reference numerals.

In the figure, a target cable A includes a shield layer A ₂ and a core wire A ₁ which is insulation-coated with the shield layer A _2.
And is separated from the ground according to the above-mentioned restriction condition (1). In addition, the cables other than the target cable A existing in the trough are grounded when they are not used according to the above-mentioned restriction condition (2). The identification device applies the frequency signal of a specific frequency to the core wire A ₁ of the target cable A, and the target housed with the trough lid opened at an arbitrary position away from the oscillator 10. A detection unit 20 for identifying the cable by detecting the signal voltage of the applied frequency signal with or without contact with the cable A.

The oscillating section 10 synthesizes the sine wave oscillating circuits 11 to 13 for oscillating different kinds of frequency signals, and the core signals A _{1 of the} target cable A by synthesizing these frequency signals.
Voltage signal synthesizing / applying circuit 14 to be applied to
_The clip 15 is sandwiched by ₁ and applies a voltage signal from the voltage signal synthesizing / applying circuit 14 to the core wire A ₁ . In this case, the clip 15 can be connected to the shield layer A ₂ .

The sine wave oscillating circuits 11 to 13 are grounded respectively according to the above-mentioned restriction condition (2) and, for example, a frequency 875 which is a frequency which is not often used normally.
Three types of sine wave frequency signals of [Hz], 3.7 [KHz], and 10 [KHz] are oscillated. Note that the oscillator circuit according to the present invention may use, for example, a circuit that oscillates a specific frequency signal at regular time intervals, in addition to this embodiment.

The voltage signal synthesizing / applying circuit 14 synthesizes the above three types of frequency signals and outputs them as a voltage signal. The detection unit 20 includes a signal electrode 21 made of a metal plate arranged in the vicinity of the target cable A that is insulated and a detection circuit 22 that is connected to the signal electrode 21 and that detects a voltage signal from the core wire A _1. An amplifier circuit 2 capable of amplifying the voltage signal and adjusting the gain of the amplification based on the above-mentioned restriction condition (3).
3, a signal identifying circuit 24 for identifying the target cable A from the amplified voltage signal, and the identified target cable A
And a display circuit 32 for displaying.

In the detection section 20, the signal electrode 21 and
Core A of target cable A₁In between, but very small,
There is a certain capacitance, and with this capacitance coupling,
Line A ₁Input to the detection circuit 22 to detect the voltage of
A buffer circuit with a very high impedance, in this example
Is a voltage using, for example, a field effect transistor
Detects the voltage signal using the flormer circuit. In addition, above
The voltage signal includes 875 [Hz] and 3.7 [K] described above.
In addition to the three types of signal frequency components, Hz] and 10 [KHz]
Contains, for example, 50 [Hz] and other noise components.
ing.

The magnitude of the voltage signal detected by the detection circuit 22 has the following main factors (1) The distance between the signal electrode 21 and the core wire A ₁ (2) The dielectric constant of the insulating layer material of the target cable A ( 3) It changes with the impedance of the detection circuit 22. Therefore, in order to cope with such a change, the amplifier circuit 23 for amplifying the voltage signal is required. Further, the amplifier circuit 23 has another important role. It has a role to search for a target cable from dozens of cables in the same trough, and the amplification circuit 23 has gain adjustment (sensitivity adjustment) for this role.
Is set to be possible.

The sensitivity is one criterion for the level of the detection signal V _IN , and the higher the sensitivity, the lower the required signal level of the detection signal V _IN . That is, the sensitivity means how far away the signal electrode 21 is from the target cable A to reliably identify the target cable A. In the case of a specific practical machine, the sensitivity of When it is high, the detection signal is generated even if the signal electrode 21 is slightly separated from the target cable A, so that the target cable A can be identified without adjusting the sensitivity. However, if there is an unused cable and the cable cannot be grounded as shown in the above condition (3),
There is a circumstance that the unused cable cannot be distinguished from the target cable. Therefore, it is indispensable to appropriately adjust the sensitivity of the amplifier circuit 23 based on the limiting condition (3).

As the sensitivity adjusting mechanism of the amplifier circuit 23, for example, the following two embodiments can be considered. (Embodiment 1) As the sensitivity adjusting mechanism, it is conceivable that a knob for continuously adjusting the detection sensitivity is provided and the sensitivity level adjusted by the knob is continuously displayed on the liquid crystal panel. In this example, when the panel display is set to 0.3V, for example, when the detected signal level exceeds 0.3V, a predetermined light or sound detection signal is output. (Embodiment 2) As another example, it is conceivable to provide a knob for stepwise adjusting the sensitivity according to the rotational position. In this example, for example, the ranks of sensitivity are set to 1 to 6, and the signal levels for generating the detection signals are set to 0.3V, 0.6V, 1.2V, 2.4V, 4.
Signal detection is performed at 8V and 9.6V.

The signal identifying circuit 24 includes band-pass filters 25 to 27 that pass three types of specific frequency signals from the above voltage signals, and smoothing of each frequency signal that has passed the band-pass filters 25 to 27. And smoothing / comparator circuits 28 to 30 for comparing each frequency signal with a reference signal, and an AND circuit 31 for performing a logical product operation of the comparison result.

The band pass filters 25 to 27 correspond to the sine wave oscillating circuits 11 to 13, and the frequency oscillated from the sine wave oscillating circuits 11 to 13 is 875 [Hz],
Three types of frequency signals of 3.7 [KHz] and 10 [KHz] are detected respectively. The noise components included in the voltage signal are removed by the bandpass filters 25 to 27.

The smoothing / comparator circuits 28 to 30 are
It is provided corresponding to the band pass filters 25 to 27, and compares each smoothed frequency signal with a predetermined reference signal,
That is, it is determined whether each frequency signal is above or below a predetermined threshold level set in each of the circuits 28 to 30, and when the frequency signal is larger than the reference signal,
The output to the AND circuit 31 is set to "1".

The AND circuit 31 is provided for smoothing each of the above three.
When the outputs from the comparator circuits 28 to 30 are both "1", the output is set to "1". This AND circuit 3
The output of 1 is 3 oscillated by the sine wave oscillation circuits 11 to 13.
This indicates that a type of frequency signal has been detected. The display circuit 32 has a lamp and a buzzer (not shown). When the output of the AND circuit 31 is "1", the lamp is turned on and the buzzer is sounded so that the cable close to the signal electrode 21 displays the frequency signal. The applied target cable A is indicated.

Next, a method of adjusting the sensitivity by using the sensitivity adjusting mechanism of the second embodiment will be specifically described. First, the signal voltage is applied from the oscillator 10 to the target cable, and then the sensitivity of the amplifier circuit 23 of the detector 20 is adjusted. In this case, it is desirable that the adjustment place is in the vicinity of the place where the signal voltage is applied so that it can be determined whether or not the cable in contact with the signal electrode 21 is the target cable A.

As a procedure for adjusting the sensitivity, first, the sensitivity is set to rank 1 and the signal electrode 21 is brought into contact with all the cables. Here, for all cables, the detection unit 2
If no detection signal is generated from 0, the target cable A
Check the voltage application status and the disconnection status from the ground. When the detection signal generated from the detection unit 20 is only the target cable A, the sensitivity is set to rank 3,
Contact the target cable A.

Here, when the detection signal is generated from the detection unit 20, it indicates that the sensitivity is appropriate, and the sensitivity adjustment is ended. When the detection signal is not generated, the sensitivity rank is increased and the sensitivity is adjusted until the detection signal is generated. For multiple cables,
When the detection signal is generated from the detection unit 20, it indicates that the cables other than the target cable A in which the detection signal is generated are unused and are not grounded. In this case, first, the rank of sensitivity is lowered only for the target cable A until the detection unit 20 generates a detection signal. For example, if the rank at that time is set to 3, then the rank of the sensitivity is further lowered by 2 steps to make the sensitivity 5 and it is checked whether or not a detection signal is generated from the detection unit 20 to the target cable A.

If the detection unit 20 can identify the target cable, the sensitivity adjustment is ended. If the target cable cannot be identified, make sure that the conductor of the unused cable is grounded. When the above work is completed, the target cable A is identified at a desired trough position, and the cables existing in the trough are checked one by one to find the target cable A. This saves the trouble of checking the cables one by one from the beginning and saves a lot of work time.

Therefore, in this embodiment, the signal voltage is applied to the target cable which is not grounded from the grounded oscillation section, and the signal voltage is applied to the gain-adjusted capacitive coupling detection section. Since the detection is performed, the signal voltage is not detected from cables other than the target cable, and the target cable can be accurately identified without making an erroneous determination.

The sensitivity of the detection unit for finding a specific cable can be increased by increasing the gain of the amplifier circuit 23 as described above, but the present invention is not limited to this. For example, in order to adjust the threshold level of the reference signals of the smoothing / comparator circuits 28 to 30, that is, in order to increase the sensitivity, it is possible to adjust the threshold level so as to be lowered.

Further, in the present embodiment, the composite signal used is a composite of three types of frequency signals, but the present invention is not limited to this, and a composite of two or four or more types of frequency signals is used. May be. In addition to the cables such as ordinary electric wires, the objects to be identified are, for example, iron pipes, steel wire armored plastic pipes in which iron wires are wound around plastic pipes, and steel stranded wires (steel wires used as tension wires for bridges, etc. Wires, and long conductive materials such as metal-reinforced fluid transportation pipes can be identified by the present invention.

[0038]

As described above, according to the present invention, the signal voltage from the oscillating unit is directly applied to the predetermined object to be identified from among the plurality of electrically conductive objects to be identified. In the method of identifying an object to be identified, which detects the signal voltage from the object to be identified by a detection unit using an electrostatic coupling method, and detects the object to be identified, the object to be identified is grounded. In addition, the object to be identified, which is not used among the oscillator and the object to be identified, is grounded, and a sensitivity adjusting unit is provided in the detector, depending on the level of the detected signal voltage. Since the sensitivity of the sensitivity adjusting means is adjusted to detect the predetermined object to be identified, the predetermined object to be identified can be accurately identified from a plurality of cables without being affected by the capacitance between the cables. This Can.

[Brief description of drawings]

FIG. 1 is a principle diagram of a typical situation and its equivalent circuit for explaining the principle of a method of identifying an object to be identified according to the present invention.

FIG. 2 is a principle diagram of another typical situation and its equivalent circuit for explaining the principle of the method for identifying an object to be identified according to the present invention.

FIG. 3 is a principle diagram of another typical situation and an equivalent circuit thereof for explaining the principle of the method for identifying an object to be identified according to the present invention.

FIG. 4 is a block diagram showing a configuration of an identification device using the cable identification method according to the present invention.

[Explanation of symbols]

10 oscillating section 11 to 13 sine wave oscillating circuit 14 potential signal synthesis and application circuit 15 clips 20 detector 21 signal electrode 22 detection circuit 23 amplifier circuit 24 signal identifying circuit 32 display circuit A target cable B~D cable A ₁ to D ₁ Core wire

Claims (1)

[Claims] 1. A signal voltage from an oscillating unit is directly applied to a predetermined object to be identified from among a plurality of electrically conductive objects to be identified, and the predetermined object is detected by a detection unit using an electrostatic coupling method. Detecting the signal voltage from the identification object,
A method for identifying an object to be identified for detecting the object to be identified, wherein the object to be identified is not grounded to earth, and the object to be identified is unused from the oscillator and the object to be identified. Each of the objects is grounded, and the detection section is provided with a sensitivity adjusting means, and the sensitivity of the sensitivity adjusting means is adjusted according to the level of the detected signal voltage to detect the predetermined object to be identified. And a method of identifying an object to be identified.