Knowledge base · Acquisition
How to use a NOVKER OTDR and get the files off it
This page covers the NOVKER NK3200 series, the NK3200D included: what the eight menu tiles and the keys mean, what an acquisition needs set, where the instrument puts the files and how to get them onto a computer. It follows the instrument's user manual and NOVKER's own catalogue in our own words. Labels from the screen are given as printed.
The instrument saves a trace as a standard .sor file, and it opens here in the browser.
By Ilya (engineer, 6 years in fibre optics) ·
On this page
What the menu and the keys mean
The instrument starts in a main menu of eight tiles. You pick one with the arrow keys and enter it with OK.
Main menu
The tiles are OTDR, Event MAP, OPM, VFL, Laser Source, Length & Tracker, RJ45 Sequence and System. OPM is the power meter and VFL the red laser for finding breaks. Event MAP runs a test on one key and draws the link as icons, with its length and the place of a break; the manual notes that this module is optional. Length & Tracker and RJ45 Sequence are for network cable. A short press of the power key switches the flashlight.
Keys
F1 to F4 do whatever the labels at the bottom of the screen say. The measure key starts and stops a test. The zoom key, used with the arrow keys, scales the trace along either axis, and OK brings it back to 1:1. The exit key returns to the previous menu.
On the OTDR screen
F1 opens the settings, F2 switches between cursors A and B, F3 saves and F4 opens the files. The link length, the total loss and the number of events are shown at the top, and the event list is below the trace. The manual names four event types: reflective, non-reflective, fiber splitter and fiber end.
Acquisition settings
The settings screen lists "Wave", "Mode", "Range", "Pulse", "Avg. Time", three thresholds, "Ior" and "Auto Analyze". The manual gives the names without explanations, so the meanings here are the usual ones for an OTDR. The range is set longer than the fibre. A short pulse separates close events and a long one reaches further; the guide on pulse width covers the trade-off. "Avg. Time" is how long the trace accumulates, and a longer time gives a cleaner trace.
"Event Loss Thre." is the loss above which a point is listed as an event. "Return Loss Thre." does the same for reflections, and "End Loss Thre." is the loss taken for the end of the fibre. If a small splice is missing from the event list, the first of the three is where to look. The guide on the detection threshold has the details.
"Ior" is the refractive index. Every distance depends on it, so take it from the cable's datasheet; why is covered in the guide on refractive index. The keys on the settings screen are F1 "Test", F2 "OK", F3 "Recover" and F4 "Cancel". The manual has no launch cable setting, so its length is subtracted from the distances by hand.
NOVKER's catalogue lists two live-test versions, the NK3200-F1 and the NK3200-F2, each built for particular traffic wavelengths. With any other model, measure a fibre only when it carries no signal.
Where the files are
After a test, F3 opens a keyboard under the heading "Save SOR": type the file name and press Enter, and the trace is saved as .sor. To skip this step, switch on "Auto Save (OTDR)" on the System screen. The instrument then saves the trace itself after every average test or auto test.
F4 opens the file list. The traces sit in folders named by date. In the list F1 opens a file, F2 deletes it and F3 renames it. NOVKER's specification names two places for the data, the internal memory and a TF card.
Getting the files to a computer
The instrument has a USB port and a slot for a TF card. The System screen has a "USB Connection" switch, which the manual lists without describing. If your traces are on the TF card, the card can also be taken out and read in a computer.
The box includes a disc with NOVKER's analysis software and the manual. NOVKER's website offers the client analysis software in three versions, for the Mini-OTDR, Multi-OTDR and Smart-OTDR lines. Each one is a program you install on a computer.
To get a PDF out of that software, NOVKER's own instructions are to install a PDF virtual printer and print the trace to it. Here the PDF sheet is made from the trace directly.
Once the files are on the computer, open them here: press Open file, or drop a file or a whole date folder onto the window. You get the trace, the event table the instrument recorded and the acquisition parameters. A PDF sheet for the trace and a link for a colleague are made right here, free.
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