System and method for rapidly measuring direct-current resistance of communication cable

Abstract

The invention relates to the technical field of cable testing, in particular to a communication cable direct-current resistance rapid measuring system and method.The communication cable direct-current resistance rapid measuring system comprises a digital direct-current resistance bridge, a measured conductor selection unit, a data transmission unit and a data processing unit, and the digital direct-current resistance bridge comprises a measuring input loop and a data output loop; one end of the measured conductor is connected with the measurement input loop through the conductor selection unit, and the other end is short-circuited; the data output loop is used for outputting data measured by the digital direct-current resistance bridge, and the data output loop is connected with the input end of the data transmission unit. The to-be-measured conductor and the digital direct-current resistance bridge are conducted through the to-be-measured conductor selection unit, after the to-be-measured conductor is connected to the digital direct-current resistance bridge, a current end outputs a certain current, a certain voltage drop is generated on a to-be-measured resistor, the voltage drop can give the resistance value of the resistor through circuit conversion, and the resistance value of the to-be-measured resistor is obtained. Therefore, the direct-current resistance of the communication cable can be quickly and accurately measured.

Description

Technical Field

[0001] The present invention relates to the technical field of cable testing, and in particular to a system and method for quickly measuring the direct current resistance of a communication cable. Background Art

[0002] Communication cables are used to transmit various signals or data. They are made of one or more pairs of mutually insulated wires twisted together. The number of conductors in each cable can reach dozens or even hundreds of thousands. In order to transmit signals stably and reliably, there are strict requirements for the DC resistance of each cable conductor. Generally speaking, it is necessary not only to control the resistance value per unit length under standard conditions (such as 20°C), but also to control the resistance imbalance of each communication unit. This requires measuring the resistance of each conductor one by one, and determining whether the cable conductor resistance meets the requirements through a large number of tedious manual calculations.

[0003] With the development and popularization of microcomputers and network technology, general manual calculations can be performed through computer software, thus saving manpower. However, in the communication cable resistance test, it is still necessary to manually enter the data into the office software for calculation, which only serves to replace the calculator.

[0004] Resistance measurement generally uses an ohmmeter, micro-ohmmeter or resistance meter. In order to achieve high-precision resistance measurement, the cable industry applies the bridge principle, such as various single-arm bridges and double-arm bridges to measure conductor resistance. The single-arm bridge is used to measure conductors with larger resistance values, and its lead resistance can be ignored; the double-arm bridge is used to measure resistors with smaller resistance values. From the measurement principle, the influence of lead resistance on the measurement result can be eliminated.

[0005] Communication cables are long and have many cores. The existing technology requires longer connecting leads for measurement, which not only increases the cost of accessories, but also brings a lot of inconvenience to the measurement. In particular, there are many related parameters, and each conductor needs to be measured. The measurement results need to be processed multiple times to get the final result. This undoubtedly increases the complexity of the test process and reduces the test efficiency. Summary of the invention

[0006] In view of the problem in the prior art that the resistance measurement operation of communication cables is complicated and the measurement efficiency is low due to their long length and large number of cores, the present invention provides a system and method for quickly measuring the DC resistance of communication cables.

[0007] The present invention is achieved through the following technical solutions: A communication cable DC resistance rapid measurement system comprises a digital DC resistance bridge, a measured conductor selection unit, a data transmission unit and a data processing unit. The digital DC bridge comprises a measurement input circuit and a data output circuit. One end of the measured conductor is connected to the measurement input circuit through the conductor selection unit, and the other end is short-circuited. The data output circuit is used to output data measured by the digital DC resistance bridge. The data output circuit is connected to the input end of the data transmission unit. The data processing unit is used to process the received data.

[0008] Preferably, the measured conductor selection unit is a switch array including a plurality of reed switch relays, the measured conductor includes a plurality of single cables, and the reed switch relays correspond one-to-one to the single cables.

[0009] Preferably, the measurement input circuit includes a potential terminal P+, a potential terminal P-, a current terminal I+ and a current terminal I-, and all are connected to the conductor to be measured.

[0010] Preferably, the data output circuit is a RS232 serial data interface.

[0011] Preferably, the data transmission unit includes a network transparent transmission module for converting the RS232 signal output by the data output loop into a LAN signal.

[0012] Preferably, the data processing unit is connected to the display unit, and the output end of the data processing unit is connected to the input end of the display unit.

[0013] Preferably, a temperature sensor is further included, and an output end of the temperature sensor is connected to an input end of the data processing unit.

[0014] A method for quickly measuring the DC resistance of a communication cable, using the communication cable DC resistance quickly measuring system, the specific steps are as follows: S1, select and number the conductor to be tested; S2, short-circuit one end of the entire conductor under test, and connect the other end to the input circuit of the digital DC bridge through the conductor under test selection unit; S3, controlling the measured conductor selection unit to measure the measured conductors one by one.

[0015] Preferably, in S1, the conductor to be measured includes a plurality of single cables, which are recorded as a first cable L1, a second cable L2, a third cable L3, ..., an nth cable L n , the corresponding resistance values ​​are recorded as: the first resistor R1, the second resistor R2, the third resistor R3...the nth resistor R n .

[0016] Preferably, in S3, during measurement, the specific process is as follows: When measuring the first resistor R1, the potential terminal P+ and the current terminal I+ of the bridge are connected to the first resistor R1, the potential terminal P- is connected to the second resistor R2, and the current terminal I- is connected to the third resistor R3; When measuring the second resistor R2, the potential terminal P+ and the current terminal I+ of the bridge are connected to the second resistor R2, the potential terminal P- is connected to the third resistor R3, and the current terminal I- is connected to the fourth resistor R4; And so on. Measure the n-2th resistor R n-2 When the bridge potential terminal P+, potential terminal P- and the n-2 resistor R n-2 Connect the potential terminal P- to the n-1 resistor R n-1 Connect the current terminal I- and the nth resistor R n connect; Measure the n-1th resistor R n-1 When the bridge's potential terminal P+, current terminal I+ and the n-1 resistor R n-1 Connect the potential terminal P- to the nth resistor R n Connect, the current terminal I- is connected to the first resistor R1; Measure the nth resistor R n When the bridge potential terminal P+, current terminal I+ and the nth resistor R n The potential terminal P- is connected to the first resistor R1, and the current terminal I- is connected to the second resistor R2.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a communication cable DC resistance rapid measurement system, which includes a digital DC resistance bridge as the measurement core, an electrical channel between a conductor to be measured and the digital DC resistance bridge can be established through a conductor to be measured selection unit, a data transmission unit is responsible for converting the data output by the digital DC resistance bridge into a format suitable for long-distance transmission, and a data processing unit receives and processes the data from the data transmission unit, and performs necessary calculations and analyses. The conductor to be measured and the digital DC resistance bridge are connected through the conductor to be measured selection unit, and after the conductor to be measured is connected to the digital DC resistance bridge, a certain current is output from the current end, and a certain voltage drop is generated on the measured resistance, and the voltage drop is input into the bridge through the potential end, and then the resistance value of the resistance can be given through circuit conversion, thereby realizing rapid and accurate measurement of the DC resistance of the communication cable.

[0018] Furthermore, the multiple terminals provided in the measurement input circuit ensure the realization of four-wire measurement, effectively eliminating the influence of lead resistance and contact resistance on the measurement result, and improving the accuracy of the measurement.

[0019] Furthermore, the use of a switch array composed of multiple reed switch relays as the conductor selection unit can achieve rapid and accurate selection and conduction of the conductor to be measured, ensuring the stability and reliability of the measurement. Reed switch relays have the advantages of fast response speed, long life, and low contact resistance, and are very suitable for such applications.

[0020] Furthermore, the integrated network transparent transmission module can convert RS232 signals into LAN signals, realize network transmission of data, and greatly improve the efficiency and range of data transmission.

[0021] Furthermore, the measurement process and measurement results are visualized through a display unit, which can intuitively display the measurement results, enable users to view the measurement data instantly, and provide the possibility for further transmission and processing of the measurement results.

[0022] Furthermore, the temperature sensor can directly read the conductor temperature, which combined with other measurement results can show the relevant performance of the conductor under standard conditions.

[0023] The invention discloses a method for quickly measuring the DC resistance of a communication cable, which can quickly and accurately measure the DC resistance of each conductor in the communication cable by measuring one by one, thereby providing strong support for the quality control and troubleshooting of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the communication cable DC resistance rapid measurement system of the present invention; Figure 2 The present invention is a flow chart of a method for quickly measuring the DC resistance of a communication cable. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0026] The invention discloses a communication cable DC resistance rapid measurement system, referring to Figure 1 , including a digital DC resistance bridge, a measured conductor selection unit, a data transmission unit and a data processing unit. The digital bridge adopts a four-wire measurement principle to isolate the potential input circuit from the current output circuit. Although it still needs to be connected to both ends of the cable through test leads, the measurement results are not affected by the connecting leads, and the accurate value of the measured resistance can be directly obtained.

[0027] The digital DC bridge includes a measurement input circuit and a data output circuit. One end of the conductor to be measured is connected to the measurement input circuit through a conductor selection unit, and the other end is short-circuited; the data output circuit is used to output the data measured by the digital DC resistance bridge. The measurement input circuit includes a potential terminal P+, a potential terminal P-, a current terminal I+ and a current terminal I-, and they are all connected to the conductor to be measured through a conductor selection unit. The conductor selection unit to be measured is a switch array including a plurality of reed switch relays, which can be automatically controlled or manually controlled according to actual needs. The conductor to be measured includes a plurality of single cables, and the reed switch relays correspond to the single cables one by one.

[0028] The data output circuit is connected to the input end of the data transmission unit. In this embodiment, the data output circuit is an RS232 serial data interface. The data transmission unit includes a network transparent transmission module for converting the RS232 signal output by the data output circuit into a LAN signal.

[0029] The data processing unit is used to process the received data. The data processing unit is connected to the display unit, and the output end of the data processing unit is connected to the input end of the display unit. In this embodiment, the display unit and the data processing unit are configured in a computer, and the output end of the temperature sensor is connected to the input end of the data processing unit, that is, the resistance data measured by the bridge enters the computer through the data transmission unit, and is comprehensively calculated by software with the cable length, the measured temperature and other data to give a test report of the cable.

[0030] Example A communication cable DC resistance fast measurement system is implemented by a digital DC resistance bridge, which is composed of a QJ36B-2A digital bridge, a network serial port transparent transmission chip CH1921, and a general programmable office software EXCEL VBA. The QJ36B-2A digital bridge is equipped with a temperature sensor, which can directly read the conductor temperature. When measuring, the unit length resistance, the unit length resistance at standard temperature, and the volume resistivity can be obtained by inputting the length and cross-section data, and can be output through the RS232 interface. The data rule is "9600, N, 8, 1", that is, the baud rate is 9600bps, no check bit, 1 start bit; 8 data bits, 1 stop bit, and the data format is: "0xFC 0xFC 0xA0 time data (6 Byte) + resistance data (6 Byte) + R20 data (6 Byte) + resistivity data (6 Byte) + temperature data (4 Byte) + 0xFA".

[0031] The network serial port transparent transmission chip CH1921 can realize two-way transparent transmission of serial port data and network data, supports TCP CLEINT / SERVER, UDP CLIENT / SERVER 4 working modes, and the serial port baud rate support range is 300bps ~ 921600bps. The network parameters and serial port parameters of the chip are configured through the host computer software NetModuleConfig. After the configuration is completed, CH9121 saves the configuration parameters to the internal storage space. After the chip is reset, the network serial port transparent transmission chip CH9121 will work according to the saved configuration values.

[0032] The bridge data is transmitted to the computer network interface and received by the VBA WINSOCK control. The received binary data is converted into text data recognizable by the software and displayed on the virtual panel.

[0033] The digital bridge virtual panel displays the measured resistance, unit resistance at 20°C, resistivity, temperature, cable length and test time as well as the connection status indicator.

[0034] The present invention also discloses a method for quickly measuring the DC resistance of a communication cable. In combination with the system for quickly measuring the DC resistance of a communication cable of the embodiment, the specific steps are as follows: S1, select and number the conductor to be measured, the conductor to be measured includes a plurality of single cables, which are recorded as the first cable L1, the second cable L2, the third cable L3...the nth cable L n , the corresponding resistance values ​​are recorded as: the first resistor R1, the second resistor R2, the third resistor R3...the nth resistor R n .

[0035] S2, short-circuit one end of the entire conductor under test, and connect the other end to the input circuit of the digital DC bridge through the conductor under test selection unit; S3, control the conductor selection unit to measure the conductors one by one. Specifically, click "Start Test" on the test interface, the system enters the digital bridge virtual panel, and when the connection status shows "connected", the instrument can perform the test operation, otherwise check whether the network cable is plugged in properly; Test the resistance of each conductor at the instrument end. After clicking "Test", the results will be displayed synchronously on the virtual panel and the instrument screen. At the same time, the data will be recorded line by line in the data recording worksheet. The details are as follows: When measuring the first resistor R1, the potential terminal P+ and the current terminal I+ of the bridge are connected to the first resistor R1, the potential terminal P- is connected to the second resistor R2, and the current terminal I- is connected to the third resistor R3; When measuring the second resistor R2, the potential terminal P+ and the current terminal I+ of the bridge are connected to the second resistor R2, the potential terminal P- is connected to the third resistor R3, and the current terminal I- is connected to the fourth resistor R4; And so on. Measure the n-2th resistor R n-2 When the bridge potential terminal P+, potential terminal P- and the n-2 resistor R n-2 Connect the potential terminal P- to the n-1 resistor R n-1 Connect the current terminal I- and the nth resistor R n connect; Measure the n-1th resistor R n-1 When the bridge's potential terminal P+, current terminal I+ and the n-1 resistor R n-1 Connect the potential terminal P- to the nth resistor R n Connect, the current terminal I- is connected to the first resistor R1; Measure the nth resistor R n When the bridge potential terminal P+, current terminal I+ and the nth resistor R n The potential terminal P- is connected to the first resistor R1, and the current terminal I- is connected to the second resistor R2.

[0036] Conductor under test R x (where x is 1, 2, ... n) After connecting to the bridge, the current terminal outputs a certain current I, which generates a certain voltage drop U on the measured resistance. This voltage drop is input into the instrument through the potential terminal and converted by the circuit to give the resistance R x Resistance value: R x =U / I.

[0037] The resistance to be measured is connected as described above. According to the bridge measurement principle, taking R1 as an example, the current I flows through R1 and R3 but not through R2, and the voltage drop U is the voltage drop across R1. After the test is completed, click "Close Test" to close the virtual panel, and click "Write Report" to generate an inspection report in the specified format.

[0038] "Save Report" is used to save the inspection report independently with the unique product number as the file name. After the test is completed, you can click "Clear Data" to perform the next test without shutting down the system.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. A communication cable DC resistance rapid measurement system, characterized in that: It includes a digital DC resistance bridge, a measured conductor selection unit, a data transmission unit and a data processing unit. The digital DC bridge includes a measurement input circuit and a data output circuit. One end of the measured conductor is connected to the measurement input circuit through the conductor selection unit, and the other end is short-circuited. The data output circuit is used to output the data measured by the digital DC resistance bridge. The data output circuit is connected to the input end of the data transmission unit. The data processing unit is used to process the received data.

2. The communication cable DC resistance rapid measurement system according to claim 1 is characterized in that: The measured conductor selection unit is a switch array including a plurality of reed switch relays, the measured conductor includes a plurality of single cables, and the reed switch relays correspond to the single cables one by one.

3. The communication cable DC resistance rapid measurement system according to claim 1 is characterized in that: The measurement input circuit includes a potential terminal P+, a potential terminal P-, a current terminal I+ and a current terminal I-, and all of them are connected to the conductor to be measured.

4. The communication cable DC resistance rapid measurement system according to claim 1 is characterized in that: The data output circuit is RS232 serial data interface.

5. The communication cable DC resistance rapid measurement system according to claim 4 is characterized in that: The data transmission unit includes a network transparent transmission module, which is used to convert the RS232 signal output by the data output loop into a LAN signal.

6. The communication cable DC resistance rapid measurement system according to claim 1 is characterized in that: The data processing unit is connected to the display unit, and the output end of the data processing unit is connected to the input end of the display unit.

7. The communication cable DC resistance rapid measurement system according to claim 1 is characterized in that: It also includes a temperature sensor, the output end of the temperature sensor is connected to the input end of the data processing unit.

8. A method for quickly measuring the DC resistance of a communication cable, characterized in that: The communication cable DC resistance rapid measurement system according to any one of claims 1 to 7 is adopted, and the specific steps are as follows: S1, select and number the conductor to be tested; S2, short-circuit one end of the entire conductor under test, and connect the other end to the input circuit of the digital DC bridge through the conductor under test selection unit; S3, controlling the measured conductor selection unit to measure the measured conductors one by one.

9. The communication cable DC resistance rapid measurement system according to claim 8, characterized in that: In S1, the conductor to be measured includes a plurality of single cables, which are recorded as the first cable L1, the second cable L2, the third cable L3, ... the nth cable L n , the corresponding resistance values ​​are recorded as: the first resistor R1, the second resistor R2, the third resistor R3...the nth resistor R n .

10. The communication cable DC resistance rapid measurement system according to claim 9, characterized in that: In S3, when measuring, the specific process is as follows: When measuring the first resistor R1, the potential terminal P+ and the current terminal I+ of the bridge are connected to the first resistor R1, the potential terminal P- is connected to the second resistor R2, and the current terminal I- is connected to the third resistor R3; When measuring the second resistor R2, the potential terminal P+ and the current terminal I+ of the bridge are connected to the second resistor R2, the potential terminal P- is connected to the third resistor R3, and the current terminal I- is connected to the fourth resistor R4; And so on. Measure the n-2th resistor R n-2 When the bridge potential terminal P+, potential terminal P- and the n-2 resistor R n-2 Connect the potential terminal P- to the n-1 resistor R n-1 Connect the current terminal I- and the nth resistor R n connect; Measure the n-1th resistor R n-1 When the bridge's potential terminal P+, current terminal I+ and the n-1 resistor R n-1 Connect the potential terminal P- to the nth resistor R n Connect, the current terminal I- is connected to the first resistor R1; Measure the nth resistor R n When the bridge potential terminal P+, current terminal I+ and the nth resistor R n The potential terminal P- is connected to the first resistor R1, and the current terminal I- is connected to the second resistor R2.

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