A cable conductor comprehensive tester

Abstract

The invention belongs to the technical field of cable detection, and discloses a cable conductor comprehensive tester, which adopts an imaging method and a comprehensive diagnosis of multiple electrical parameters to comprehensively measure parameters such as the effective cross-sectional area of ​​the cable conductor, the DC resistance of the long conductor, the DC resistance of the conductor per unit length, the capacitance of the long cable, the capacitance of the cable per unit length, and the ambient temperature; specifically, the effective cross-sectional area of ​​the cable end face is accurately measured by collecting the cable end face image, and compared with the traditional method of measuring the "diameter" of the cable using a caliper, the measurement accuracy is greatly improved, and there is no restriction on the shape and type of the measured cable; the DC resistance of the cable is measured by a resistance measurement module, the resistance per unit length is calculated by the nominal length, and the actual length of the cable conductor is calculated by comparing the resistance value of the long conductor with the resistance value of the intercepted reference conductor; the capacitance of the cable is measured by a capacitance measurement module, and the actual length of the cable is calculated by comparing the cable capacitance with the capacitance of the intercepted reference cable.

Description

Technical Field

[0001] The invention belongs to the technical field of cable detection, and more specifically, relates to a comprehensive tester for cable conductors. Background Art

[0002] The quality and quantity of cables invested in projects are of great significance to power supply safety. If unqualified cables are used for lighting, air conditioning and other circuits in various buildings and railway projects, it will bury huge safety hazards for the projects. The current market size of the cable industry has reached trillions of yuan, but the quality of cable products is not optimistic. For example, the cable core wires of some cable products are "shrunk and slimmed down" to make them "thick at both ends and thin in the middle", the rubber layer is thick and the core wire is thin, which reduces the conductor cross-sectional area of ​​the cable, the conductor ratio of the alloy cable does not meet the standard, the conductor density is uneven, and the cable length is less than its nameplate length. The existing method of calculating the resistance value per unit length by measuring the DC resistance of the cable conductor and then calculating the cable length, or the method of using DC resistance to reversely infer the conductor cross-sectional area, causes less damage to the cable, but it is easy to miss defective products whose cable length and cross-sectional area change in proportion.

[0003] The traditional method of using a caliper to measure the conductor diameter and calculate the cross-sectional area has a large error due to the fact that the cable conductor is not a regular circle and there are gaps when multiple strands are twisted. The existing twisted pair cable detection technology disclosed in the patent document with application number CN200910261930 generates relative movement between a cable including multiple conductors and a magnetic field, detects the electrical signal induced in the conductor in response to the magnetic field, senses the change in the electrical signal caused by the relative movement, and detects defects in the cable through the change. This detection method focuses more on the detection of the breakage or splicing of the core wire inside the cable, and cannot detect the uniformity of the cross-sectional area of ​​the cable core wire. An accurate non-destructive testing device is urgently needed to meet the detection needs of cable conductors at the engineering site. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a cable conductor comprehensive tester, which aims to provide an accurate detection means for cable conductor parameter detection and compliance determination.

[0005] To achieve the purpose of the present invention, according to one aspect of the present invention, a cable conductor comprehensive tester is provided, comprising a main control unit, an imaging module, an imaging module interface and a power supply interface;

[0006] Among them, the imaging module communicates with the main control unit through the imaging module interface. The imaging module is used to take a cross-section image of the cable conductor under test. The main control unit calculates the cross-sectional area of ​​the cable conductor based on the acquired image and obtains the length of the cable conductor based on the cross-sectional area. The power supply interface is used to connect to an external power supply to power other units or modules.

[0007] Preferably, the above-mentioned cable conductor comprehensive tester further includes a capacitance measurement module and a capacitance test interface;

[0008] One side of the capacitance test interface is connected to the capacitance measurement module, and the other side is used as the external interface of the cable conductor comprehensive tester for connecting to the device under test for capacitance measurement; the capacitance test module and the main control unit have a connection relationship for signal interaction.

[0009] Preferably, the above-mentioned cable conductor comprehensive tester further includes a resistance measurement module and a resistance test interface;

[0010] One side of the resistance test interface is connected to the resistance measurement module, and the other side is used as another external interface of the cable conductor comprehensive tester for connecting to the device under test for resistance measurement; the resistance test module also has a connection relationship with the main control unit for signal interaction.

[0011] Preferably, the imaging module of the above-mentioned cable conductor comprehensive tester includes an optical imaging system and an imaging fixture; the optical imaging system is used to capture the image of the cross-section of the cable under test, and one or more groups of imaging fixtures arranged on the optical imaging system lens barrel are used to fix the test piece so that the central axis of the test piece is parallel to the optical axis of the optical imaging system lens.

[0012] Preferably, the imaging module of the above-mentioned cable conductor comprehensive tester further includes a distance baffle, which fits the cross section of the cable under test so that the distance between the tested device and the lens of the optical imaging system is fixed to obtain a high-resolution image.

[0013] Preferably, the imaging module of the above-mentioned cable conductor comprehensive tester also includes a diffuser plate and a light source; the diffuser plate and the light source are arranged on the side of the optical imaging system lens away from the device under test, and are used to provide a uniform illumination light source for the device under test, thereby obtaining a clear, high-resolution image.

[0014] Preferably, the above-mentioned cable conductor comprehensive tester also includes a human-computer interaction unit having a connection relationship with the main control module for signal interaction; the main control unit sends the interface image of the test piece collected by the imaging module to the human-computer interaction unit for display; the human-computer interaction unit is also used to receive input detection parameters and send them to the main control unit, and is used to display the cable conductor cross-sectional area and cable conductor length calculated by the main control unit.

[0015] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0016] The cable conductor comprehensive tester provided by the present invention adopts the method of taking an image of the cross-sectional area of ​​the cable conductor and calculating the effective cross-sectional area of ​​the cable conductor according to the image obtained by the image taking; the cable resistance and capacitance are measured by a parallel capacitance measurement module and a resistance measurement module; and the main control unit further obtains the DC resistance of the cable conductor per unit length, the cable capacitance per unit length and other groups of parameters required for cable conductor parameter detection and compliance determination according to a preset algorithm and the measured resistance and capacitance through calculation; the means of obtaining the cross-sectional area of ​​the cable conductor by imaging greatly improves the measurement accuracy and precision of the cross-sectional area of ​​the cable conductor compared with the traditional method of using a caliper to measure the "diameter" of the cable, and there is no restriction on the shape and type of the measured cable; on the other hand, the comprehensive tester integrates multi-parameter detection means into one, and one device can meet the needs of multi-parameter detection of cables on the engineering site, and the actual measurement results show that the cable conductor comprehensive tester has greatly improved the measurement accuracy of the cable conductor capacitance, resistance and cable length. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of the principle of the cable conductor comprehensive tester provided by the present invention.

[0018] Figure 2 It is a schematic diagram of the imaging module principle in the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] The cable conductor comprehensive tester provided by the present invention adopts imaging method and comprehensive diagnosis of multiple electrical parameters to measure parameters such as effective cross-sectional area of ​​cable conductor, DC resistance of long conductor, DC resistance of conductor per unit length, capacitance of long cable, capacitance of cable per unit length and ambient temperature. The cross-sectional area test is specifically to accurately measure the effective cross-sectional area of ​​the cable end face by collecting the image of the cable cross section. There are many methods for obtaining the effective cross-sectional area of ​​the cable end face by processing and calculating the cable end face image. In the present invention, the processing and calculation are performed according to the algorithm built into the main control unit; the algorithm in a specific embodiment is based on the difference between the imaging grayscale of the cable conductor material and the cable coating layer, and the number of pixels I occupied by the grayscale of the cable conductor is calculated, and the actual area s of a single pixel of the image of the cable cross section is calculated according to the imaging parameters of the image of the cable cross section, so as to obtain the total cross-sectional area measurement value S=Is of the cable conductor.

[0021] Compared with the traditional method of using a caliper to measure the "diameter" of the cable, this method of obtaining the cross-sectional area measurement value of the cable conductor by imaging the cross-section of the cable conductor avoids the measurement error caused by the irregular circle of the cable conductor core wire and the existence of gaps when multiple strands are twisted. The cross-sectional area measurement accuracy is greatly improved, and there is no restriction on the shape and type of the measured cable.

[0022] The cable conductor comprehensive tester provided by the present invention measures the DC resistance of the tested cable through a precision resistance measurement module, and then calculates the resistance per unit length according to the nominal length through a preset algorithm through a main control module, and obtains the measured value of the cable conductor length by comparing the resistance value of the long conductor with the resistance value of the intercepted reference conductor. Similarly, the capacitance of the tested cable is measured through a precision capacitance measurement module, and then the measured value of the cable conductor length is obtained by comparing the capacitance of the long cable with the capacitance of the intercepted reference cable through a preset algorithm through a main control module.

[0023] Reference Figure 1 , a cable conductor comprehensive tester provided by an embodiment includes a resistance measurement module, a capacitance measurement module, a main control unit, an imaging module, an imaging module interface, a resistance test interface, a capacitance test interface and a power supply interface;

[0024] Among them, one side of the capacitance test interface is used as an external interface of the comprehensive tester for connecting to the device under test for capacitance measurement, and the other side is connected to the capacitance measurement module; one side of the resistance test interface is used as another external interface of the comprehensive tester for connecting to the device under test for resistance measurement, and the other side is connected to the resistance measurement module; the capacitance test module and the resistance test module are both electrically connected to the main control unit; the imaging module communicates with the main control unit through the imaging module interface, and the imaging module is used to take an image of the cross-section of the cable conductor under test, and the main control unit calculates the cross-sectional area of ​​the cable conductor based on the obtained image, and obtains the length of the cable conductor based on the cross-sectional area; the power supply interface is used to connect to an external power supply to power other units or modules.

[0025] Reference Figure 2 The imaging module in the embodiment includes an optical imaging system, an imaging fixture, a fixed-distance baffle, a diffuser, and an LED lamp as a light source; the optical imaging system lens module is KS10A411, and the specific parameters are shown in Table 1. The inner diameter of the lens barrel is 35 mm and the length is 60 mm. The two sets of imaging fixtures arranged on the lens barrel are used to fix the object under test so that the central axis of the object under test is parallel to the optical axis of the lens. The imaging fixture can be one or more sets, and different imaging fixtures can be selected according to the actual cross-sectional area measurement requirements of the cable to be tested; the fixed-distance baffle fits the cross-section of the object under test so that the distance between the object under test and the lens is fixed to obtain a high-resolution image, and the diffuser and LED lamp provide a uniform illumination light source for the object under test, thereby obtaining a clear, high-resolution image. The processor of the main control unit processes a single image for no more than 2 seconds.

[0026] Table 1 Lens optical parameters

[0027]

[0028]

[0029] In a specific example, the optical imaging system of the imaging module has 10 million pixels, and the photosensitive element type is CMOS; the module size is 38mmX38mm (±1mm); the photosensitive size is 1 / 2.3”; the adjustable parameters include brightness, contrast, hue, saturation, clarity gamma, white balance, backlight contrast, and exposure value; the adjustable resolution range includes: 640×480, 1024×768, 1280×720, 1280×960, 1600×1200, 1920×1080, 2048×1536, 2592×1944, 3264×2448, 3648×2736; the focus mode is adjustable, manual focus or fixed focus.

[0030] The resistance measurement module has a wide resistance test range of 10mΩ to 200kΩ with seven test ranges; the test speed is variable: slow 2.5 times / second, fast 10 times / second; it has a zeroing function.

[0031] The measurement frequency of the capacitance measurement module is 10kHz, 1kHz, 120Hz, and 100Hz. The test signal level is 1.0V, 0.3V, and 0.1V. The range mode is hold and automatic. The measurement speed includes fast and slow. It has short-circuit clearing and open-circuit clearing functions. The equivalent mode includes series connection and parallel connection (PAr). The internal resistance of the signal source is 30Ω or 100Ω.

[0032] The error of measuring the effective cross-sectional area of ​​the cable conductor by using the cable conductor comprehensive tester provided in the embodiment is less than 3%; the accuracy of the cable DC resistance measurement is ±0.05%+2 digits, and it has a temperature correction function; the error of the conductor length obtained according to the resistance measurement is less than 1%; the cable capacitance measurement accuracy can reach 0.1%, and the error of the conductor length measured according to the capacitance is less than 1%.

[0033] The cable conductor comprehensive tester provided by the present invention introduces image recognition technology and combines multiple electrical parameter measurements according to actual cable testing needs. It measures parameters such as the cross-sectional area, resistance per unit length and length of the cable conductor through a variety of means, providing users with a more effective and accurate means for cable conductor detection.

[0034] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A cable conductor comprehensive tester, characterized in that: It includes a main control unit, an imaging module, an imaging module interface and a power supply interface; the imaging module communicates with the main control unit through the imaging module interface, the imaging module is used to take a cross-section image of the measured cable conductor, the main control unit calculates the cross-sectional area of ​​the cable conductor according to the obtained image, and obtains the length of the cable conductor according to the cross-sectional area; the power supply interface is used to connect to an external power supply to power the main control unit and the imaging module; The imaging module includes an optical imaging system and an imaging fixture; the optical imaging system is used to collect images of the cross-section of the cable under test, and one or more imaging fixtures arranged on the optical imaging system lens barrel are used to fix the tested piece so that the central axis of the tested piece is parallel to the optical axis of the optical imaging system lens, the imaging module also includes a fixed-distance baffle, the fixed-distance baffle fits the cross-section of the cable under test, so that the distance between the tested piece and the optical imaging system lens is fixed to obtain a high-resolution image, the imaging module also includes a diffuser and a light source; the diffuser and the light source are arranged on the side of the optical imaging system lens away from the tested piece, and are used to provide a uniform illumination light source for the tested piece, thereby obtaining a clear, high-resolution image; it also includes a capacitance measurement module and a capacitance test interface; one side of the capacitance test interface is connected to the capacitance measurement module, and the other side is used as an external interface of the cable conductor comprehensive tester, which is used to connect to the tested piece for capacitance measurement; the capacitance measurement module and the main control unit have a connection relationship for signal interaction; it also includes a resistance measurement module and a resistance test interface; One side of the resistance test interface is connected to the resistance measurement module, and the other side is used as another external interface of the cable conductor comprehensive tester for connecting to the device under test for resistance measurement; the resistance test module also has a connection relationship with the main control unit for signal interaction.

2. The cable conductor comprehensive tester according to claim 1, characterized in that: It also includes a human-computer interaction unit that has a connection relationship with the main control module for signal interaction; the main control unit sends the interface image of the test piece collected by the imaging module to the human-computer interaction unit for display; the human-computer interaction unit is also used to receive input detection parameters and send them to the main control unit, and is used to display the cable conductor cross-sectional area and cable conductor length calculated by the main control unit.

Images