How to locate and repair optical cable faults
Optical communication is an era that dominates information transmission. Optical fiber and cable lines are laid and used in large quantities. The protection and maintenance of optical cable lines has become the top priority of the communication industry. However, the line will often be interrupted due to various reasons, which brings great trouble to the maintenance personnel of the optical cable line.
If there is an optical fiber interruption, we first consider the optical cable fault and take certain positioning measures for it, first check the outside and then go to the transmission. External, such as: fiber breakage, base station power interruption, etc. Then test the transmission equipment. Therefore, how to improve the accuracy of cable line fault data location is helpful to accurately judge faults, especially the conversion of fiber length, cable length, and ground length.
First of all, it is necessary to understand how to use the instrument and master the use of the instrument, which is helpful for accurate measurement.
1. Set the parameters of OTDR. When using OTDR testing, the instrument parameters must be set first, the most important of which is to set the refractive index, pulse width and test wavelength of the test fiber. Only by accurately setting the basic parameters of the test instrument can conditions be created for accurate testing.
2. Use the zoom function of the instrument. Using the zoom function of the OTDR, the cursor can be accurately set on the corresponding inflection point, and the graph can be zoomed in to 25 meters/grid by using the zoom function key, so that a relatively accurate test result with a resolution of less than 1 meter can be obtained. Set with the shortest possible pulse width.
3. Adjust the accurate test range file. For different test range files, the distance resolution of OTDR test is different. When measuring fiber optic obstacle points, you should choose the test range file (1.5 times) that is larger than the measured distance and the nearest test range file, so as to make full use of the instrument's own accuracy. and display window to perform measurements.
Accurate and complete original chart data should be established during the maintenance and management process. These accurate and detailed optical cable line files are the basic basis for fault measurement and location. Therefore, negligence should not be neglected in the maintenance and management process, and authentic, credible and complete line information should be established.
When monitoring the optical cable connection, record the cumulative length of the optical fiber from the test end to each joint point and the total attenuation value of the optical fiber in the relay section, and also register the model of the test instrument and the set value of the refractive index during the test. Accurately record all remaining optical cables. Record in detail the length of optical cable reels at each joint pit, special location, S-shaped laying, room entry, etc., and the length of optical fiber reels at splice boxes, terminal boxes, ODF racks, etc., so that they can be deducted when converting the route length of the fault point.
In general, the two ends of the fiber optic cable line need to be tested for bidirectional faults, and then combined with the original data for analysis, and then prepare to determine the specific location of the fault. When there are no obvious features on the link around the fault point and the specific site cannot be determined, then we can take the measurement method at the nearest joint, or excavate at the obstacle point of the preliminary test, and the test instrument at the end station is in a real-time measurement state. Use the comparison function to place the cursor reasonably. Sometimes the change of the ground insulation of the metal shield can be used to locate the damaged point with a locator