NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
The working principle of the cable identification instrument In order to identify the cable reliably and accurately, it is necessary to add a special signal to the identified cable. The signal needs to be received by a special receiver, and the cable can be identified by using this feature. In order to identify the cable reliably and accurately, the generator needs to add a special signal to the identified cable. The signal needs to be received by a special receiver, and this characteristic can be used to identify the cable. out the cable you are looking for. The generator feeds periodic unipolar voltage pulses into the cable to be identified, which needs to be grounded at the far end to ensure sufficient current flows through the cable.
The system should be designed so that the return current does not return from the same cable. This can be achieved. The direction of the pulse current fed into the cable can be used as a clear identification criterion. The outgoing current only passes through this cable. Return currents flow through all other adjacent cables, but with opposite polarities. In addition to the actual difference in current direction, the magnitude of the current is also an identifying feature, the current flowing out is only through one cable, while the return current can pass through several cables, which means that the current flowing out is higher than the return current flowing through the other cables. big. The task of the receiver is to detect the direction and magnitude of the current flowing through the cable.
For this purpose, a current sensor is used as a sensor with an amplifier in series in the circuit, the sensor clamps the cable under test, the magnetic field generated by the current flowing through the cable induces a voltage in the coil of the sensor, the voltage polarity Determined by the current direction and the direction of the sensor coil. In order to obtain voltage polarity with apparent current direction, test all cables in a bundle with the same correct direction. The voltage induced in the sensor coil is displayed in the meter head. If the sensor is connected in the above-mentioned way, the direction of the pointer swing can show the current direction, that is, only the pointer of the cable where the current flows out is biased to one side, and this is the cable you are looking for.
All other cables carry only return current, the pointer is deflected to the other side, or there is no pulsating current, and the pointer does not deflect. The amplifier adjuster on the receiver adjusts the signal strength. I hope the above introduction about the cable identification instrument can bring you some help.
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