RU70999U1 - DEVICE FOR TESTING TWO INSULATED CONDUCTORS SELECTED FROM A GENERAL WIRED COUPLE HARNESS - Google Patents

Abstract

The utility model relates to devices for determining the pairing of conductors in cables and bundles, consisting of twisted pairs of conductors and can be used to determine whether each twisted pair is correctly twisted - i.e. these conductors are together or selected from different pairs.

The technical result consists in the ability to determine the alignment of conductors among themselves in a strong electromagnetic field, the device gives greater accuracy when measuring short lengths of conductors and conductors in a common screen (shielded twisted pair), the device is less expensive to operate, especially for testing modern high-quality cables. For measurement, only one end of the pair is required - i.e. The method allows you to check an already laid cable or harness. The claimed technical result is achieved due to the fact that the device for testing two insulated conductors selected from a common bundle of twisted pairs, containing a display, a processor, is characterized in that it contains an auto-switch, a multivibrator on a timer, the function of which is to convert capacitance to frequency and transmit a pulse signal a processor whose function is to measure the frequency or duty cycle of the input signal.

Description

Application area

The utility model relates to devices for determining the pairing of conductors in cables and bundles consisting of twisted pairs of conductors and can be used to determine whether each twisted pair is correct - i.e. these conductors are together or selected from different pairs.

State of the art

Twisted-pair electric cable is widely used in telecommunication and computer networks. The cable is a set of several pairwise twisted conductors coated with a dielectric in a common insulating sheath. The pairing of conductors in a pair allows to reduce both the mutual influence of the pairs on each other, and the general electromagnetic interaction of the pairs with the environment. To ensure the most stable signal transmission in the electric circuit, two conductors twisted together must be used. However, very often in cables with a large number of twisted pairs, a pair of conductors from different twisted pairs is erroneously combined into a circuit. This leads to a deterioration in the quality of signal transmission and further numerous errors in the transmission of data along such a circuit.

The prior art patent US 6002247 for a method for determining the correct pairing by connecting a pair of wires in a circuit. The method offers a method of measuring pairing. The circuit combines two arbitrary wires. An impulse is applied to one of them. In the second, the magnitude of the induced voltage is measured. It is argued that pairing can be judged by the magnitude of the pickup.

The disadvantages of the method include the inefficiency of the method, because it does not allow determining pairing in an environment of strong electromagnetic fields, it is not so accurate when measuring wires of short length and wires in a common screen (shielded twisted pair), since the magnitude of the pickups in such cables is quite small and it is problematic to estimate the difference in pickups.

Also disadvantages include the fact that the method is quite expensive, especially for testing modern high-quality cables. Because they use

thicker conductors and insulation with a better dielectric, as well as denser twisting, inductive coupling in pairs decreases, respectively, and the induced signal in a twisted pair decreases. In order to assess the difference in pickups and conductors from different pairs, you will have to use higher-quality and, therefore, more expensive ADCs.

The prior art patent WO 2006069810 for a method of assembling an electrical connector, and the shape of the connector used to assemble it and a device for determining the correct assembly of the connector. Here, a device is described for determining the correctness of a cable cut into a connector. However, only the geometric parameters of the device and its mating connector are described. No physical measurements are made. The electrical circuit used allows us to judge only about the geometric correctness of the cable cut into the connector pin. If the cable is in the correct position, the contact is present in the connector; if it is in the wrong position, it is absent. Pairing of conductors in the cable is not checked.

The patent US 4,553,088 is known from the prior art. A device is described which is used together with a machine for cutting twisted pairs of conductors into a connector with numbered contacts. The device is electrically connected with the indicator lights of the machine, as well as with a tool for terminating the conductor in the connector, which is also used as an electric probe. If the signal conductor is incorrectly cut into a grounded contact, the device makes a sound.

The device is able to determine only the polarity of the conductors in the circuit, and not their pairing. The disadvantage of this solution is that to determine the correct polarity, it is necessary to cut both ends of a pair of conductors. In this method, measurements can only be carried out under industrial / laboratory conditions. The closest solution should be considered patent US 3763426 for a method and apparatus for testing twisted pairs of conductors for detecting defects in electrical insulation or measuring the step of twisting or ending the conductor or detecting gaps in the conductor. Here is described a device for monitoring the characteristics of a pair of insulated conductors during their lay.

However, the pairing of conductors is not checked, because All measurements are made on only one pair of conductors. Among other things, the capacitance between the electrodes installed at a certain distance from each other in the device through which a twisted pair of conductors is passed is monitored. Insulation conductors here stands in

as the dielectric of the capacitor, and the electrodes of the device - its plates. Gaps in the conductor or changes in the pitch of the conductors lead to changes in the capacitance of such a capacitor. When such changes are detected, the alarm is turned on and the pairing line stops.

The method for measuring capacitance is not described here (only a certain device “capacitance meter” is indicated). Measurements are carried out only on a relatively small segment of twisted pair, and the conductors themselves are not used as capacitor plates, but act as dielectrics of the capacitor, the capacitance of which is measured.

The technical result of this device consists in the ability to determine the alignment of conductors among themselves in an environment of strong electromagnetic fields, the device gives greater accuracy when measuring short lengths of conductors and conductors in a common screen (shielded twisted pair), the device is less expensive to operate, especially for testing modern high-quality cables . For measurement, only one end of the pair is required - i.e. The method allows you to check an already laid cable or harness.

Brief Description of the Drawings

Figure 1 shows a block diagram of a device that implements the method, where 1 is a twisted pair wire, 2 is an auto-switch, 3 is a multivibrator on a timer that performs the function of a capacitance to frequency converter, 4 is a processor, 5 is a display, 6 is a device case.

Device essence

The claimed technical result is achieved due to the fact that the device for testing two insulated conductors selected from a common bundle of twisted pairs, containing a display, a processor, is characterized in that it contains an auto-switch, a multivibrator on a timer, the function of which is to convert capacitance to frequency and transmit a pulse signal a processor whose function is to measure the frequency or duty cycle of the input signal.

The principle of operation of the device is based on connecting a bundle of insulated conductors to a circuit breaker, which connects a pair of conductors intended for testing, to a capacitance-to-frequency converter implemented on a timer, the pulse signal from which is supplied to the processor, where the frequency or duty cycle of the input signal is measured. Switching using auto-switch pairs

conductors from a common bundle, conduct such measurements for all pairs in the bundle. By analyzing the results of such measurements, a table is displayed on the graphical indicator showing the numbers of the pairs of conductors twisted together, as well as the capacitance measured for each twisted pair.

This device allows you to distinguish pairs of conductors twisted together from two conductors taken from different twisted pairs, thus determining the pairing of twisted conductors in multi-pair cables and bundles.

The operation of the device is based on measuring the electrical capacitance of two individual conductors. From the course of general physics it is known that a system of two oppositely charged conductors is called a capacitor. The capacitance of a capacitor is directly proportional to the area of its plates and inversely proportional to the distance between them:

,

where ε is a constant, S is the area of the plates, d is the distance between the plates (see Formula (34.1) [1]).

Thus, any pair of wires in a cable or harness can be used as a capacitor. Since the distance between the conductors twisted together and taken from different pairs is different, it can be expected that the capacitance of a twisted pair of conductors is much higher than the capacity of non-twisted conductors.

The capacitance meter can be implemented through the use of a typical timer switching circuit in self-oscillating mode. As a timer, for example, a domestic microcircuit 1006 VI1 can be used.

(see [2, Fig. 4.33a.]).

The circuit allows you to get a capacitance to frequency converter. According to [2, see 4.43 and 4.44]:

Connecting a pair of conductors with resistances R as the capacitance Ct at the output, we will have a signal of frequency f, which will differ for a pair of conductors twisted together and conductors taken from different pairs.

To connect the cable to the device, the auto-switch unit (2) is used. It is controlled by the central processor (4) and allows you to choose any

two conductors from a cable connected to the device. The selected conductors are connected to the multivibrator on the timer (3) as a capacitance. The pulse signal from the multivibrator unit is fed to the signal input (GPIO) of the processor (4). The processor (4) measures the time during which the GPIO input is in the state of the logical unit Ttrue and the time of the subsequent state of the logical zero Tfrue. Thus, the frequency of the signal f is:

, and the duty cycle will be Tfalse.

Next, the processor (4) sequentially using the auto-switch (2) iterates over all possible combinations of two conductors in the cable, remembers the frequency of the incoming signal for each of them. Based on the formula 34.1 (see [1]), because the distance between the twisted and non-twisted conductors is different, the signal frequency for the conductors twisted with each other will be noticeably smaller than the frequency of the signal in the conductors of different pairs. According to the measurement results, the processor (4) displays on the graphic indicator (5) a diagram showing the pairing of conductors in the cable, as well as the value of the measured capacitance for each twisted pair.

The processor used must have signal inputs and outputs for controlling the auto-switch and graphic indicator (GPIO), for example, Microchip 18F4 series CPUs. Any small-sized liquid crystal display, for example, Ampire black-and-white LCD indicator of brand AG 12232A, can be used as a graphic indicator .

The claimed device allows you to determine pairing in an environment of strong electromagnetic fields, since they do not affect the result of reading the capacitance of the conductor.

The device has great accuracy for short lengths of conductors and conductors in the common screen (shielded twisted pair), since the magnitude of the pickups in such cables is quite small and it is problematic to estimate the pickup difference by conventional methods, while the capacitance difference is quite significant.

Modern high-quality cables use larger conductors and insulation with a better dielectric. In such cables, the inductive coupling in pairs decreases, respectively, and the induced signal in the pair decreases. In order to assess the difference in pickups in twisted pairs and conductors from different pairs, it is necessary to use higher quality and, therefore, more expensive

ADC. Since the claimed ADC device is not used and the element base is simpler and cheaper, it can be argued that the claimed device is less expensive to test modern high-quality cables.

Since only one end of the pair is required for measurement, the device allows you to check the cable already laid.

Information sources:

1. Elementary textbook of physics in 3 volumes. Electricity, magnetism Volume 2. Landsberg G.S. Fizmatlit 2003 ISBN: 5922103504

2. "Circuitry of analog and analog-digital electronic devices", Volovich G.I. Ed. House "Dodeca-XXI" 2005, ISBN 5941200749. Chapter 4.5. Analog timers.

Claims (1)

A device for testing two insulated conductors selected from a common bundle of twisted pairs, comprising a display, a processor, characterized in that it contains an auto-switch, a multivibrator on a timer, the function of which is to convert capacitance to frequency and transmit a pulse signal to a processor, whose function is to measure frequency or duty cycle input signal.