Knowledge base · Acquisition
How to use a Grandway OTDR and get the files off it
This page covers two Grandway instruments, the FHO5000 and the pocket Mini1000: what the menu items mean, what an acquisition needs set, where the instrument puts the files and how to move them to a computer or a phone. It follows Grandway's user manuals in our own words. Labels from the instrument's screen are given in quotation marks.
Both instruments save 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 means
The OTDR is one tile in the main menu, next to the other tools built into the instrument.
Main menu
On the FHO5000 the tiles are OTDR, Laser Source, OPM, VFL, FLM and EFD. OPM is the optical power meter and VFL is the red laser for finding breaks. FLM, the fiber link map, runs a test with only the wavelength chosen and draws the link as icons. EFD shows the picture from an optional fibre microscope. The Mini1000 has OTDR, VFL, OLS (the light source), OPM, FLM and SETUP.
Auto and manual
In Auto mode the instrument sets the range and the pulse width itself. Manual mode lets you set both. A test is also run in one of two ways: an average test accumulates the trace for the set time, and a real-time test keeps refreshing it until you stop. The FHO5000 has a key for each, and on the Mini1000 they are two buttons on the touch screen.
On the trace screen
The FHO5000 puts the trace functions on the keys F1 to F4: cursors A and B, zoom and shift, zoom to a region, and the switch between the trace and the event list. A second page adds an overlay of other traces, LSA loss and attenuation, and adding or removing an event by hand. On the Mini1000 you drag markers A and B with a finger and pinch to zoom, and the "1:1" button brings the whole trace back.
Acquisition settings
The setup screen of the FHO5000 lists "Test Wave", "Test Mode", "Test Time", "Test Range", "Pulse Width", "Resolution", "Unit" and "Launch cable length". The manual advises a range of one and a half to two times the length of the fibre. A wider pulse reaches further and makes the dead zone larger, and a longer test time gives a cleaner trace. High resolution takes more sample points. Once you set the range the instrument adjusts the pulse width to it, and you can still change the pulse by hand. The trade-off is covered in the guide on pulse width.
The FHO5000 can account for a launch cable in two ways. You enter its length, or you tell the instrument to go by events: everything before the first event is then the launch fibre, and the stretch between the last two events is the receive fibre. The Mini1000 manual describes no such setting, so there the length of a launch cable is subtracted by hand.
On the Mini1000 the refractive index sits under "Parameter Setup", next to the end threshold, the loss above which an event is taken for the end of the fibre. The manual says the index is normally left at its default and warns that a wrong value throws off the distance. The value that belongs there is the one from the cable's datasheet; why is covered in the guide on refractive index. Both instruments also take pass/fail thresholds for loss and reflection, and those are yours to set for the job.
An ordinary model must not be connected to a fibre that carries a signal. The Mini1000 shows a "Light WARNING" alarm when it finds light in the fibre, and the manual says to stop the measurement at once. FHO5000 models with a built-in filter can test a live fibre at their out-of-band wavelength.
Where the files are
On the FHO5000 the FILE key opens file management. With auto save on, each trace goes into a folder named after the test date, either as a .sor or as a .sor with a PDF report, whichever the "Auto save" setting says. The same settings screen chooses where auto save writes, the storage card or a USB stick, and how the file name is built: a prefix you type, then optionally the wavelength, pulse width and range, then a running number. Without auto save you store the trace yourself with "Save" or "SaveAs" on the file screen. Under "Multi Function" the instrument saves a screenshot as a BMP picture and makes a PDF report from the current trace.
The Mini1000 has no save button. Traces are kept only when "Auto Save" is switched on in SETUP; otherwise, the manual says, the test files are not saved. Switch it on before the first measurement. Saved traces sit in date folders under OTDRDATA, and screenshots under DATA.
Getting the files to a computer or a phone
The Mini1000 connects with a Type-C data cable. First switch on "USB Disk mode" in SETUP, then plug the cable in. The computer shows the instrument's folders, and you copy the .sor files out of OTDRDATA.
The FHO5000 has a mini USB port for transferring files to a PC over a cable, and USB ports for a memory stick. A stick plugged into the instrument appears in file management next to the storage card, and "File Operation" there has copy and paste. Auto save can also be pointed at the stick from the start.
Over Bluetooth, the FHO5000 PRO and some Mini1000 models work with Grandway's Android app. The app runs a measurement and shows the .sor files stored in the instrument. With the FHO5000 it can send a file on from the phone, and with the Mini1000 it makes a PDF report. Grandway's program for the PC is called OTDRviewer.
Once the file is on the computer or the phone, open it here: press Open file, or drop the file or the 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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