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–Cable Length Tester
The cable identifier is the main function of identifying a cable from a bundle of cables. It is a common equipment for cable erection, migration, maintenance and troubleshooting. The search for cable identifiers is divided into spot cable identifiers and dead cable identifiers according to service conditions.
The cable identifier is the main function of identifying a certain cable from a bundle of cables. It is a common equipment for cable erection, migration, maintenance and troubleshooting. The search for cable identifiers is divided into spot cable identifiers and dead cable identifiers according to service conditions.
So, what basic matters need to be paid attention to when using the live cable identification instrument? 1. If there is a ground or branch in the middle of the live cable. Then only the portion of the cable before grounding or branching can be identified. After the coupling signal is added to the cable, no obvious effective signal can be detected with the flexible coil and the receiving box, and the transmitter can be left about 3 meters away to avoid signal interference.
If there is still no valid signal display, it means that the copper shield of the cable has a disconnection point or the grounding of both ends of the cable is unreliable. At this time, the grounding condition of the cable to be identified should generally be checked. If it is found that the shielding layer has a disconnected point, the cable identifier can be used to ground the disconnected point before and after, and then identify it in sections. 2. If the receiver is about 3m away from the host, there is a signal for verification and identification, but there is no signal at the site to be identified, or the signal is too small to be recognized.
It means that the cable to be identified must have multiple metal outer sheath grounding points. In this case, the power failure of the cable to be identified must be segmented and identified. At this time, the core wire can be used as a signal channel for identification, that is, the core wire at the beginning and end of the cable. line ground for identification. After turning on the power switch, the human body should not touch the output terminal and the metal leakage part. After turning off the power, wait for the output indicator to go out completely before removing the wires to avoid electric shock.
3. When the device is not used for a long time. Please take out the battery in the host and the receiving box and store it separately. There are 2 search methods for the cable identification instrument: 1. The search method of the dead cable identification instrument The search method of the dead cable identification instrument is basically the same as that of the live identification instrument. The generator feeds periodic unipolar voltage pulses into the cable to be identified. .
The cable needs to be grounded at the far end to ensure sufficient current flows through the cable, the direction of the pulse current fed into the cable can be used as an obvious identification criterion, the current flowing out is only through this cable, all other The return currents flow through the adjacent cables, but their polarities are opposite, and the direction and magnitude of the current flowing through the cable are detected by the receiver. It has an amplifier and is connected 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 is determined by the direction of the current and the direction of the sensor coil, thus reaching the cable identification. 2. Searching method of live cable identification instrument When the line is live, we cannot affect the normal operation.
When identifying the cable with a point, the inductive method is used for measurement, and the high-frequency signal is transmitted through the caliper, and the receiver receives the signal characteristics and filters it through software and hardware. During phase identification, when the receiving caliper clamps the cable according to the current direction, the current meter of the identified cable is deviated to the right, accompanied by sound and light indication. The current direction of other cables is opposite to the current direction of the identified cable. The pointer of the ammeter is left to the left, and there is no sound and light indication, which reflects the uniqueness of the identified target cable, and it is easy to remove the identified cable from multiple cables. The difference is made; since the signal current strength on the identified cable is the same across the board, the electromagnetic signal strength received by the receiving caliper along the cable is the same. In principle, the identified cable is not limited by the length of the identified cable.
The above are the precautions for the use of the cable identification instrument analyzed and summarized by the editor. I hope it can be helpful to everyone.
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