Facility and test method for cable assembly

Abstract

The invention relates to a facility (1) for cable assembly and a test method, the facility having a conductor support (30) which is provided for transporting and holding at least one conductor (40), a time-domain reflectometry measuring device (10) which is provided for performing a high-frequency measurement, and a contact device (20) which is movable relative to the conductor (40) and the time-domain reflectometry measuring device (10) and which is connected to the time-domain reflectometry measuring device (10) via a high-frequency connection (12), wherein the contact device (20) is designed to contact the conductor (40) in a high-frequency manner. The invention also relates to a test method for cable assembly at the facility (1).

Description

Technical Field

[0001] The present invention relates to a facility for assembling cables and a testing method for assembling cables at the facility. Background Technology

[0002] In automated cable assembly, with at least one plug automatically secured to the conductor, the DC characteristics of the assembled conductor are tested using a cable detector in the final process step of the prior art. DC characteristics include continuity, short circuit, and / or insulation. In the prior art, conductor length determination is only performed randomly in a manual process step, which involves opening the cable coil and measuring the conductor length. Testing of the conductor assembled on one side is also performed only on a DC basis using short circuit and insulation tests. However, high-frequency characteristics (such as reflection, impedance, and / or running time) cannot be tested using the cable detectors of the prior art.

[0003] Publication text KR 20 200 065 167 A relates to an apparatus for measuring the length of a cable wound on a roller (particularly a heavy-duty cable reel). Here, a TDR (Time Domain Reflectometry) length sensor is fixed to the internal open end of the cable inside the reel and measures the remaining length of the cable on the roller.

[0004] Publication US 2005 052 190 A1 relates to a digital TDR system. This publication describes how the length of a cable still wound on a roller can be determined. The accuracy of the TDR system is improved by performing multiple measurements and determining an average value.

[0005] Publication US 2013 162 262 A1 relates to a system for testing wire harnesses. The system includes one or more TDR engines and is capable of sequentially applying TDR excitation to branches of the wire harness and collecting the resulting TDR waveforms. The waveforms are analyzed to determine whether the wire harness meets quality standards. In particular, a wire harness assembly (wire harness clamp) is used to couple the wire harness to the system. For coupling, an operator presses each clamp or bracket of the wire harness into a support within the wire harness assembly.

[0006] Public document WO 2014 204 484 A1 relates to the determination of the length of a cable wound on a roller. To determine the length, measurements are performed within the ultrasonic range.

[0007] The apparatuses and systems described in the prior art have the disadvantage of being unsuitable for integration into automated process flows. In particular, the connection between the conductor to be tested and the measuring device is not described or performed in a manual step. Furthermore, the systems are not suitable for measuring short conductors, i.e., conductors with lengths in the lower centimeter range. Finally, the conductors in the prior art are only measured at one end, i.e., relative to the ground, and therefore cannot be measured in multi-core cables. Summary of the Invention

[0008] Therefore, the object of the present invention is to overcome the above-mentioned disadvantages and to provide an apparatus and method for automating high-frequency testing of wires, especially wires assembled in an assembly facility.

[0009] The above-mentioned objectives are achieved by the facility according to the invention and the testing method according to the invention. Further advantageous embodiments of the invention can be derived from the examples, description, and drawings.

[0010] The aforementioned objective is achieved in particular by a facility for cable assembly having a conductor support, a time-domain reflectometry (TD-RS) device, and a contact device. The conductor support is configured to transport and hold at least one conductor, the TD-RS device is configured to perform high-frequency measurements, and the contact device is movable relative to the conductor and the TD-RS device and is connected to the TD-RS device via a high-frequency connection, wherein the contact device is capable of contacting the conductor in a high-frequency manner.

[0011] The facility for cable assembly features an integrated testing system. It automates the assembly of conductors and performs end-to-end testing on the assembled conductors. Manual testing, including opening conductor coils and designing and measuring conductors on the cabling slab, is eliminated. Furthermore, TDR measurements can be used to identify breaks in the conductors. Overall, the testing process becomes faster and more reliable.

[0012] Preferably, the time-domain reflectometry device has at least two channels, and these channels can operate in either standalone or differential mode. In standalone mode, two conductors can be measured simultaneously. This generally reduces the testing time. In differential mode, multiple cores of the conductor can be measured against each other, thus enabling the testing of multi-core conductors.

[0013] Preferably, the time-domain reflectometry (TD-RS) device is based on a sequential equivalent time sampling method and includes a jump generator with a rise time of less than 100 ps, ​​preferably less than 70 ps, ​​and most preferably less than 65 ps, and a measurement bandwidth of greater than 5 GHz, preferably greater than 8 GHz, and most preferably greater than 10 GHz. The TD-RS device is particularly free of dead time. These parameters enable the measurement of very short signal travel times, allowing for the reverse measurement of very short conductor lengths. Measurement of short conductors is advantageous because conductors shorter than 30 cm (approximately 1 foot) are also assembled in the cable assembly. Furthermore, very high spatial (along the length direction) resolution is achieved. This high resolution enables accurate length measurement and precise identification of breaks or mechanical faults in the conductor, such as grounding clamps connected to the conductor. Measurement speeds for conductors up to 16 meters in length are less than 4 seconds.

[0014] Preferably, the wires can be wound around a coil, and even more preferably assembled on one or both sides. The wires are preferably wound around a coil to save space and facilitate handling. In automation processes, it is advantageous if the wires can remain permanently wound as a coil, as unwinding the coil takes time and unwound wires are difficult to handle. In cable assembly, the wires are assembled on one or both sides, i.e., for a permanent connection with connecting elements such as plugs or sockets. Compared to unassembled wires, the geometry of the connecting elements must be considered, especially when the wires are in contact, to provide a reliable connection.

[0015] Preferably, the connection using a high-frequency method includes the same impedance of the time-domain reflectometry device, the contact portion of the conductor, and the conductor itself. Here, "same impedance" also means approximately the same impedance, thus enabling the reception of a measurement signal (reflected signal) suitable for reliable measurement. Impedance is particularly important for high-frequency signals. When the impedance difference is too large, the transmitted measurement signal attenuates severely during the transition from one medium to another, resulting in a received measurement signal that is too weak for reliable evaluation.

[0016] Preferably, the contact device includes a contact pin subjected to spring stress. When the wire is pressed against the contact pin, the spring tension generates a sustained clamping force on the contact pin on the wire, the first wire end, or the connecting element. This ensures reliable contact between the contact pin and the wire. If the connection is merely loose, undesirable movement at the facility may cause a gap between the wire and the contact device. A gap will result in a significant impedance difference, which will negatively impact high-frequency measurements.

[0017] Preferably, the time-domain reflectometry device includes a high-frequency multiplexer. The high-frequency multiplexer enables simultaneous measurement of multiple conductors, thereby accelerating the entire testing process.

[0018] Preferably, the facility also includes a personal computer for controlling measurements and processing measurement data from the time-domain reflectometry device, and / or a programmable logic controller for controlling the automated power supply to the conductors at the contact points. In automated cable assembly, manual steps should be reduced to a minimum or ideally eliminated. The use of a personal computer and / or programmable logic controller eliminates manual steps. Automated processes are faster and generally more reliable.

[0019] In particular, the above objective is achieved through a testing method for cable assembly at a facility, the facility including at least one conductor support, a contact device, and a time-domain reflectometry device connected to the contact device via a high-frequency connection, wherein the method comprises the following steps: positioning the conductor relative to the contact device by means of the conductor support, aligning the contact device with the conductor so that the contact device can contact the conductor, testing the conductor by means of the time-domain reflectometry device, and after the test, moving the contact device in a direction away from the conductor so that the conductor can move freely by means of the conductor support.

[0020] All steps are automated, ensuring reliable testing of the wire. In particular, a reliable, high-frequency connection is achieved between the wire and the time-domain reflectometry (TD-SCDMA) measuring device through the movement of the contact device. Here, the wire holder must position the wire under test solely within the test area, with the contact device performing and monitoring the contact. By guiding the wire into the contact device, preferably with a form-fit connection, the additional positioning step is eliminated. After testing the wire, the contact device releases it, allowing the wire holder to continue its original movement, for example, in a second direction transverse to the contact device. A few, and typically one-dimensional, movements are advantageous for automation.

[0021] Preferably, the step of aligning the contact device with the wire includes pressing the contact device against the wire. Pressing the contact device, and especially the contact pin, against the wire provides a simple, reliable, and detachable connection between the wire and the contact device. Therefore, a connection can be quickly established and then released again after measurement.

[0022] Preferably, the testing steps include determining the wire length and / or the wire breakage.

[0023] Preferably, the testing steps include determining DC characteristics. In addition to high-frequency measurements, DC characteristics can also be tested. Therefore, comprehensive testing of the conductors improves the overall quality of all conductors.

[0024] Preferably, the testing method further includes the following steps: conveying the wire to subsequent process steps, and providing the subsequent wire to the contact device by means of a wire holder. Through these process steps, a closed automated testing process is established.

[0025] Preferably, the test method also includes an initial step: calibrating the test method via measurements at a conductor of a specified length. The initial step refers to performing a calibration before conducting various conductor tests. This calibration can be performed, for example, at the start of facility commissioning, the start of a new assembly line, the start of a facility shift, or other suitable / necessary times. Calibration improves the reliability of the measurements. Attached Figure Description

[0026] The embodiments are described below with reference to the accompanying drawings. Here are shown:

[0027] Figure 1 A schematic illustration shows an embodiment of a facility for cable assembly;

[0028] Figure 2 A diagram illustrating an embodiment of TDR measurement is shown; and

[0029] Figure 3 A schematic illustration of an embodiment of a circuit with respect to impedance is shown.

[0030] The embodiments are described in detail below with reference to the accompanying drawings. Detailed Implementation

[0031] Figure 1 An embodiment of a facility 1 for assembling cables or wires is shown. Facility 1 can include multiple modules configured to assemble wires 40 using at least one plug. These modules can include, for example, crimping modules for contacts and / or engagement modules for plugs. For a fast process, forwarding and processing between and at modules are automated. At the end of cable assembly, the assembled wires 40 should be tested. Figure 1 Facility 1, as shown, integrates testing into the automated process.

[0032] For the testing process, a wire holder 30, which accommodates the assembled wire 40, is introduced into the test area 50. Assembling the wire 40 is possible, but not mandatory. In the illustrated embodiment, the wire holder 30 clamps the wire 40 to securely hold and transport it. In other embodiments, other types of holding are feasible. Movement of the wire holder 30 can be achieved by a robotic arm or a conveyor belt. The test area 50 preferably features a positioning aid 52. In the illustrated embodiment, the positioning aid 52 is an aperture with an opening. For example, the opening can be circular and adapted to the maximum outer diameter of the first wire end 41. In other embodiments, the positioning aid 52 can simply include markings characterizing the test area 50. The wire holder 30 positions the wire 40, particularly the first end 41 of the wire 40, within the test area 50. In a preferred embodiment, the wire holder 30 moves the wire 40 along a second direction Y.

[0033] The first end 41 of the conductor 40 is preferably assembled, i.e., equipped with a plug. The plug is preferably a high-frequency type plug. The conductor 40 can be wound into a coil to save transport space. The second end 42 of the conductor 40 can be assembled or not. In principle, the conductor length can be arbitrary. The conductor length is particularly in the range of 2.5 cm to 16 m. Preferably, the conductor 40 for automated cable assembly is a single-wire antenna conductor with an impedance of 50 Ω or a stranded and shielded 2 / 4-wire data cable with a differential impedance of 100 Ω.

[0034] The contact device 20 contacts the lead wire 40 to be measured. The contact device 20 is capable of contacting the lead wire 40 at a high frequency, which is important for performing TDR measurements. The contact device 20 preferably has a contact pin 22 for measurement, which is elastically positioned by means of a spring element 24. The contact pin 22 is preferably of a metal design to transmit high-frequency signals. An optional guide device 28 can assist in guiding the lead wire 40 into the contact device 20. Figure 1 In this configuration, the auxiliary device 28 is formed by at least two tapered sides. Other configurations are also possible. The contact device 20 is connected to the time-domain reflectometry device 10 via a high-frequency connection 12. The high-frequency connection 12 enables the transmission of both DC and AC signals, particularly in the high-frequency range. Preferably, the high-frequency connection 12 is connected to the contact device 20 via a component 26. Component 26 particularly includes a 50Ω impedance plug-in connector.

[0035] Contact device 20 is movable relative to lead wire 40 and time-domain reflectometry device 10. For lead wire testing, contact device 20 is aligned with the first end 41 of lead wire 40. Contact device 20 is preferably movable along a first direction X, in the direction of lead wire 40 or the first lead wire end 41 arranged in test area 50. Contact device 20 moves in particular along the direction of lead wire 40 with integrated centering and fixed stops until lead wire 40 moves the elastically placed contact pin 22 and compresses spring element 24. Here, spring element 24 is only partially compressed, thereby applying pressure on contact pin 22 in the direction of lead wire 40. Spring element 24 has a working stroke, which is approximately located at the latter third of the maximum design. In alternative embodiments, other elements with a return force upon compression can be used. Through the spring mechanism, contact pin 22 is in a braking manner in a persistent contact with the first end 41 of lead wire 40, ensuring a connection using a high-frequency method. Electrical signals can be provided from assembly 26 via spring element 24 or a separate connection to contact pin 22.

[0036] In one implementation, good contact can be achieved, for example, when the contact pin moves a certain distance. Distance offset can be detected and the measurement process triggered at the time-domain reflectometry (TDR) measuring device. In particular, the end position of the contact can be detected by a sensor, and TDR measurement can be initiated.

[0037] To provide a high signal amplitude at conductor 40 and obtain a clear result signal for evaluation, a connection must be established between the time-domain reflectometry device 10 and conductor 40. For connections utilizing high-frequency methods, the impedances, i.e., wave resistances, of the time-domain reflectometry device 10, the contacts of conductors 12 and 20, and conductor 40 must have the same impedance (Z). w Z L )(See Figure 3 In the above embodiments, due to external specifications, a 50Ω impedance is used in the case of a single-wire conductor. A 50Ω impedance is standard for measuring equipment and test pieces (such as antenna wires). In coaxial conductors, the geometry, particularly between the inner and outer conductors and the dielectric, determines the wave resistance, i.e., the impedance.

[0038] The conductor 40 is tested using a time-domain reflectometry (TD-RS) device 10. To integrate the TD-RS device 10 into the production facility, a dual-channel differential TD-RS device suitable for the manufacturing environment is selected. Standard TD-RS devices are typically designed to be very large and more suitable for laboratory use. The selected TD-RS device 10 is based on a so-called "sequential equivalent time sampling" method, thus achieving virtual sampling intervals of up to 10 ps. Using these sampling intervals, the conductor 40, especially conductors with a dielectric constant of 1.7, can be resolved at a distance of approximately 1.15 mm. The TD-RS device 10 in this embodiment has a (jump) generator and a scanning module. The jump generator has a rise time of less than 65 ps, and the scanning measurement bandwidth is greater than 10 GHz. The TD-RS device 10 has no dead time, meaning that even very short conductors 40 with a length greater than 25 mm can be measured or pre-calibrated.

[0039] The domain reflective measuring device 10 can operate in standalone (single-ended) or differential mode (differential) mode, with two channels capable of measuring or inspecting multi-core conductors. The measurement time, known as the scan time, depends on the measurement mode, the number of measurement points, the length of the conductor 40, the generator frequency, and the resolution. In one embodiment, measuring two conductors 40 with 8192 data points takes approximately 0.5 seconds. In another embodiment, a standalone operation for measuring a 16-meter-long conductor 40 takes approximately 2.5 seconds. Four or eight channels can also be operated using a high-frequency multiplexer, enabling simultaneous testing of multiple conductors 40.

[0040] Figure 2 An embodiment of TDR measurement is illustrated. Measurement points are displayed on the horizontal axis, and signal amplitudes are displayed on the vertical axis. The wire length is determined by the propagation velocity and runtime through the initial reflection (steep negative amplitude) between the contact pin 22 and the first end 41 of the wire 40, particularly at the high-frequency plug (see position P1), and the total reflection (sharply rising positive amplitude) at the second end 42 of the wire 40, particularly the open, unassembled wire 40 (see position P2). Each measurement point corresponds to a specific resolution for the length of the wire 40 at a sampling rate of 10 ps. To improve accuracy, the system can be pre-calibrated using measurements of a defined length. Interruptions in the wire 40 are manifested as significant deviations from the illustrated reflection pattern and lengths below the minimum required length for the wire 40.

[0041] Using the facility 1 or the test method, DC characteristics (e.g., continuity and / or short circuit) and high-frequency characteristics (e.g., reflection, impedance and / or running time) can be determined and preferably automatically checked at the end of the line at the end of the automated assembly of the conductor 40.

[0042] In the described embodiment, a personal computer takes over control of the measurement and data processing of the time-domain reflectometry device 10. Automatic power supply is controlled via a programmable logic controller. After testing, the contact device 20 is reset to its initial position, and the lead wire 40 is further transported for subsequent processing steps, such as extraction. Identical or alternative lead wire supports 30 are positioned and subsequent lead wires 40 are held, and the process begins anew.

[0043] Reference tag list

[0044] 1. Facilities

[0045] 10 Time Domain Reflectometry Device

[0046] 12 high-frequency connections

[0047] 20 contact devices

[0048] 22 contact pins

[0049] 24 spring elements

[0050] 26 components

[0051] 28. Import auxiliary device

[0052] 30 wire support

[0053] 40 wire

[0054] 41 First end

[0055] 42 Second End

[0056] 50 test areas

[0057] 52 Positioning Auxiliary Device

[0058] P1 First Position

[0059] P2 Second Position

[0060] X First Direction

[0061] Y is the second direction.

Claims

1. A facility (1) for cable assembly, having a) a plurality of modules, which are provided for the assembly of at least one plug with a conductor wire (40); b) a forwarding and processing between and at the modules automatically; c) a time-domain reflectometry device (10), which is provided for performing high-frequency measurements; and d) a contact device (20), which is movable relative to the conductor wire (40) and the time-domain reflectometry device (10) and which is connected to the time-domain reflectometry device (10) via a high-frequency connection (12), wherein the contact device (20) is able to contact the conductor wire (40) in a high-frequency manner; e) a personal computer for controlling the measurement of the time-domain reflectometry device (10) and for processing the measurement data of the time-domain reflectometry device and a programmable logic controller for controlling the automatic feeding of the conductor wire (40) at the contact device (20); f) the conductor wire holder (30) moves transversely to the contact device (20) in a second direction (Y) and positions the conductor wire (40) in a test region (50); g) the contact device (20) for contacting the conductor wire (40) moves in a first direction (X) towards the conductor wire (40) arranged in the test region (50); and h) the contact device (20) comprises a contact pin (22) which is spring-stressed. The time-domain reflectometry device (10) has at least two channels, and the channels can be operated in a single-ended mode or in a differential mode. The time-domain reflectometry device (10) is based on the "successive equivalent time sampling" method and has a jump generator, wherein the jump generator has a rise time of less than 100 ps and a measurement bandwidth of more than 5 GHz. The conductor wire (40) can be wound onto a coil and can be assembled on one or both sides. The connection in a high-frequency manner comprises the same impedance of the contact of the conductor wire (12, 20) and of the conductor wire (40) of the time-domain reflectometry device (10). The time-domain reflectometry device (10) comprises a high-frequency multiplexer. The method has the following steps: a) automatic processing of the conductor wire (40) at the modules; b) automatic forwarding of the conductor wire (40) between the modules transversely to the contact device (20) in a second direction (Y); c) positioning of the conductor wire (40) in a test region (50) relative to the contact device (20) by means of the conductor wire holder (30) and controlling the positioning by a programmable logic controller; d) aligning of the contact device (20) in a first direction (X) towards the conductor wire (40) arranged in the test region (50) with the conductor wire (40) in order to enable the contact device (20) to contact the conductor wire (40); e) testing of the conductor wire (40) by means of the time-domain reflectometry device (10) and controlling the testing by a personal computer; and f) automatic forwarding of the conductor wire (40) between the modules transversely to the contact device (20) in a second direction (Y). ​ b) a wire carrier (30) provided for the transmission and retention of at least one wire (40); wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The facility of claim 1, wherein, ​ 3. The facility according to claim 1 or 2, wherein, ​ 4. The facility according to claim 1 or 2, wherein, ​ 5. The facility of claim 1 or 2, wherein, ​ 6. The facility of claim 1 or 2, wherein, ​ 7. A method for testing a cable assembly at a facility (1), the facility comprising at least one conductor support (30), a contact device (20) and a time-domain reflectometry measuring device (10), the time-domain reflectometry measuring device being connected with the contact device (20) via a high-frequency connection (12), wherein, ​ ​ ​ ​ ​ ​ f) after the test, moving the contact device (20) in the first direction (X), i.e. away from the conductor (40), to enable the conductor (40) to be moved freely by means of the conductor holder (30); g) further conveying the conductor (40) to a subsequent process step; and h) providing a subsequent conductor (40) to the contact device (20) by means of the same conductor holder (30) or another conductor holder.

8. The test method of claim 7, wherein, The step of aligning the contact device (20) with the conductor (40) comprises pressing the contact device (20) to the conductor (40).

9. The test method of claim 7 or 8, wherein, The step of testing comprises determining the conductor length and / or determining an interruption of the conductor (40).

10. The test method of claim 7 or 8, wherein, The step of testing comprises determining the direct current characteristic.

11. The testing method according to claim 7 or 8, further having an initial step: Calibrating the testing method via a measurement at a conductor (40) having a defined length.

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