A method and system for detecting twisted pair of twisted pair cables

Abstract

The present invention provides a twisted pair detection method and system for twisted pair cables, and the steps are as follows: setting the access information of the object to be tested, including the number of twisted pair pairs to be tested and the correct twisted pair relationship; switching the test point and measuring the impedance value; analyzing and judging the measured impedance value, and obtaining the twisted pair relationship of the twisted pair according to the judgment condition. The present invention solves the problem that the automatic test and the manual test cannot distinguish the twisted pair relationship, and avoids the waste of time and manpower costs caused by discovering the welding wire error during the whole machine debugging.

Description

Technical Field

[0001] The invention relates to the field of automatic testing, and in particular to a system and method for automatically testing a twisted pair cable, analyzing its twisted pair relationship and obtaining a result of whether the twisted pair relationship of a tested object is correct. Background Art

[0002] With the continuous improvement of the level of industrial automation, the internal cable network scale of various large-scale equipment, such as space shuttles, ships and warships, trains and subways, and even ordinary cars, is increasing. There are many types of cables inside the complex cable network, among which low-frequency signal lines often use twisted pairs to reduce external interference. Therefore, the correct welding of twisted pairs is of great significance to the quality of data transmission. Wrong lines, missing lines, and mixed lines may cause communication interruptions or errors, seriously affecting product quality. At present, cable testing is mainly based on automated or semi-automated testing, supplemented by manual testing in some special testing requirements. For twisted pair cables, existing automatic testers or manual tests can only distinguish short circuits / open circuits, crossovers / wrong pairs, etc., and cannot distinguish twist pair errors. Generally, the problem of twisted pair errors in twisted pair cables is not discovered until communication errors occur in the debugging of the entire machine, and the troubleshooting time and cost are very high. Summary of the invention

[0003] The technical problem solved by the present invention is to overcome the deficiencies of the prior art and provide a twisted pair detection system and method for twisted pair cables to ensure the stability of twisted pair communication and the correctness of data.

[0004] The technical solution of the present invention is: a method for detecting twisted pairs of twisted pair cables, comprising:

[0005] Set the access information of the object under test, including the number of twisted pairs under test and the correct twisted pair relationship;

[0006] Switch the test points and measure the impedance value;

[0007] The measured impedance value is analyzed and judged, and the twisted pair relationship of the twisted pair is obtained according to the judgment conditions.

[0008] The objects to be tested are multiple pairs of twisted-pair cables, the number of test points is an even number, there is no upper limit on the number of test points, and there are at least two pairs of twisted-pair cables of the same material and equal length, that is, 4 test points.

[0009] The correct twisted pair relationship is the twisted pair relationship obtained by the tested twisted pair cable according to the requirements of the drawing.

[0010] When switching the test points, only two points are connected at a time, and the impedance value between the two points is measured and recorded.

[0011] The switching of the test point and measuring the impedance value comprises:

[0012] Through the switching circuit, the point to be measured is switched; let point i and point j be a pair of twisted wires and form a group, and measure the impedance value Aij of each pair of twisted wires;

[0013] Switch the point to be measured again, connect two points in different groups that should not be twisted, and measure an impedance value B.

[0014] The analyzing and judging the measured impedance value and obtaining the twisted pair relationship of the twisted pair according to the judging condition include:

[0015] Compare each impedance value Aij with the obtained impedance value B in turn, and judge whether the twisted line pair is correct according to the judgment conditions; if correct, output the result; if incorrect, the test point corresponding to the incorrect line pair enters the error search test.

[0016] The judgment condition is: for two conductors of the same material and length, the impedance value in the untwisted state is at least 1.5 times greater than the impedance value of the two wires in the twisted state, that is, B>1.5Aij.

[0017] The specific implementation of the error finding test is as follows:

[0018] For all the line pairs that are judged to be incorrect, the points to be tested are rearranged and combined into pairs, and the impedance value Cmn between any two lines except the two points ij that have been measured is measured; m and n are the points to be tested;

[0019] Compare 1.5 times Cmn with B. If B>1.5Cmn, then point m and point n are determined to be in an actual twisted pair relationship.

[0020] The sum of the line pairs that have been judged to be correct and the m and n line pairs that have been judged to be the actual twisted pair relationship is the actual twisted pair relationship of all the tested line pairs.

[0021] A twisted pair detection system for twisted pair cables, comprising: a setting unit, a scanning test unit, and an analysis unit;

[0022] The setting unit is used to set the access information of the object under test, including the number of twisted pair pairs under test and the correct twisted pair relationship;

[0023] The scanning test unit is used to realize the switching of test points and the measurement of impedance values. Only two points are connected at one time, and the impedance value between the two points is measured and recorded.

[0024] The analysis unit is used for analyzing and judging the measured values, and obtaining the twisted pair relationship of the twisted pair according to the judging conditions.

[0025] The objects to be tested are multiple pairs of twisted-pair cables, the number of test points is an even number, there is no upper limit on the number of test points, and there are at least two pairs of twisted-pair cables of the same material and equal length, that is, 4 test points.

[0026] The advantages of the present invention compared with the prior art are:

[0027] (1) The twisted pair test module of the present invention completes the identification of the connection relationship and the twisted state of the twisted pair under test, and can reflect the actual connection state of the object under test without omission.

[0028] (2) The present invention provides the faulty wiring of the object under test through error finding test, which can facilitate workers to make direct and rapid corrections and improve efficiency.

[0029] (3) The present invention solves the problem that automatic testing and manual testing cannot distinguish the twisted pair relationship, thereby avoiding the waste of time and manpower costs caused by discovering welding wire errors during whole machine debugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the twisted pair detection workflow. DETAILED DESCRIPTION

[0031] like Figure 1 As shown, a method for detecting twisted pairs of twisted pair cables comprises:

[0032] Set the access information of the object under test, including the number of twisted pairs under test and the correct twisted pair relationship;

[0033] Switch the test points and measure the impedance value;

[0034] The measured impedance value is analyzed and judged, and the twisted pair relationship of the twisted pair is obtained according to the judgment conditions.

[0035] The objects to be tested are multiple pairs of twisted-pair cables, the number of test points is an even number, there is no upper limit on the number of test points, and there are at least two pairs of twisted-pair cables of the same material and equal length, that is, 4 test points.

[0036] The correct twisted pair relationship is the twisted pair relationship obtained by the tested twisted pair cable according to the requirements of the drawing.

[0037] When switching the test points, only two points are connected at a time, and the impedance value between the two points is measured and recorded.

[0038] The switching of the test point and measuring the impedance value comprises:

[0039] Through the switching circuit, the point to be measured is switched; let point i and point j be a pair of twisted wires and form a group, and measure the impedance value Aij of each pair of twisted wires;

[0040] Switch the point to be measured again, connect two points in different groups that should not be twisted, and measure an impedance value B.

[0041] The analyzing and judging the measured impedance value and obtaining the twisted pair relationship of the twisted pair according to the judging condition include:

[0042] Compare each impedance value Aij with the obtained impedance value B in turn, and judge whether the twisted line pair is correct according to the judgment conditions; if correct, output the result; if incorrect, the test point corresponding to the incorrect line pair enters the error search test.

[0043] The judgment condition is: for two conductors of the same material and length, the impedance value in the untwisted state is at least 1.5 times greater than the impedance value of the two wires in the twisted state, that is, B>1.5Aij.

[0044] The specific implementation of the error finding test is as follows:

[0045] For all the line pairs that are judged to be incorrect, the points to be tested are rearranged and combined into pairs, and the impedance value Cmn between any two lines except the two points ij that have been measured is measured; m and n are the points to be tested;

[0046] Compare 1.5 times Cmn with B. If B>1.5Cmn, then point m and point n are determined to be in an actual twisted pair relationship.

[0047] The sum of the line pairs that have been judged to be correct and the m and n line pairs that have been judged to be the actual twisted pair relationship is the actual twisted pair relationship of all the tested line pairs.

[0048] Example

[0049] Add a twisted pair test module to the tester. Take the object to be tested as a group of 4 pairs of wires of the same material and equal length, that is, 8 test points as an example. Among the 8 test points, there are one pair at (1, 2), one pair at (3, 4), one pair at (5, 6), and one pair at (7, 8). The specific implementation method of the twisted pair detection work is as follows:

[0050] 1) Tester settings

[0051] Connect the object to be tested to the tester through the interface. Set the parameters on the tester, record the group of twisted pairs mentioned above in one row, and record the twisted wires in the tested wire pair as one pair.

[0052] 2) Scan test

[0053] Step 1: Switch the access point to be tested through the switch unit of the twisted pair test module. Measure the impedance values ​​of the four pairs of wires (1, 2), (3, 4), (5, 6), and (7, 8) that should be twisted as mentioned above.

[0054] Step 2: Switch the measured point again, connect two points (1, 8) in the same group that should not be twisted, and measure an impedance value.

[0055] 3) Result analysis

[0056] Compare the 4 impedance values ​​a obtained in step 1 of the scan test in sequence12 、a 34 、a 56 、a 78 Compared with the impedance value B obtained in step 2, if 1.5 times a 12 、a 34 、a 56 、a 78 If it is less than B, the relationship between the four pairs of wires is correct and the result is output. If it does not meet the above judgment conditions, assume that a 12 , a 56 If the value does not match, it is determined that the wire has an incorrect twisted pair relationship, and the corresponding test points (1, 2) and (5, 6) enter the error search test

[0057] 4) Error finding test

[0058] The impedance values ​​between each test point of the two incorrect line pairs are measured in sequence, namely (1, 5), (1, 6), (2, 5), (2, 6), and c is obtained. 15 、c 16 、c 25 、c 26 , according to the judgment conditions, if c 15 、c 26 It meets the correct impedance value range, which is 1.5 times c 15 、c 26 If it is less than B, then (1,5) (2,6) is judged to be the actual phase twisted state.

[0059] In summary, the actual twisted pair relationships of the tested cables are (1, 5), (3, 4), (2, 6), and (7, 8). Twisted pair errors occur at test points 1, 2, 5, and 6.

[0060] Parts of the present invention that are not described in detail belong to common knowledge among those skilled in the art.

Claims

1. A method for detecting twisted pairs of twisted pair cables, characterized in that include: Set the access information of the object under test, including the number of twisted pairs under test and the correct twisted pair relationship; Switch the test points and measure the impedance value; Analyze and judge the measured impedance value, and obtain the twisted pair relationship of the twisted pair according to the judgment conditions; The object to be tested is a plurality of twisted pairs, the number of test points is an even number, there is no upper limit on the number of test points, and at least two pairs of twisted pairs of the same material and the same length, that is, 4 test points; The correct twisted pair relationship is the twisted pair relationship obtained by the tested twisted pair cable according to the requirements of the drawing; When switching the test points, only two points are connected at a time, and the impedance value between the two points is measured and recorded; The switching of the test point and measuring the impedance value comprises: Through the switching circuit, the point to be measured is switched; let point i and point j be a pair of twisted wires and form a group, and measure the impedance value Aij of each pair of twisted wires; Switch the point to be measured again, connect two points in different groups that should not be twisted, and measure an impedance value B; The analyzing and judging the measured impedance value and obtaining the twisted pair relationship of the twisted pair according to the judging condition include: Compare each impedance value Aij with the obtained impedance value B in turn, and judge whether the twisted line pair is correct according to the judgment conditions; if correct, output the result; if incorrect, the test point corresponding to the incorrect line pair enters the error search test; The judgment condition is: the impedance of two wires of the same material and length in an untwisted state is at least 1.5 times greater than the impedance of the two wires in a twisted state, that is, B>1.5Aij; The specific implementation of the error finding test is as follows: For all the line pairs that are judged to be incorrect, the points to be tested are rearranged and combined into pairs, and the impedance value Cmn between any two lines except the two points ij that have been measured is measured; m and n are the points to be tested; Compare 1.5 times Cmn with B. If B>1.5Cmn, then point m and point n are determined to be in an actual twisted pair relationship. The sum of the line pairs that have been judged to be correct and the m and n line pairs that have been judged to be the actual twisted pair relationship is the actual twisted pair relationship of all the tested line pairs.

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