EXFO FTB-500 (Window XP) - Manual (Page 126)

Using the Optional Built-In Power Meter and VFL
116 FTB-500
Measuring Power or Loss
Measuring Power or Loss
Measuring absolute power or link (insertion) loss is done the same way,
except for the referencing step. You can take power or loss measurements
and save them for further analysis.
To perform power or loss measurements:
1. If necessary, perform an offset nulling (see Nulling Offsets on
page 110).
2. Check your fibers and clean them properly.
3. For loss measurements, reference your power meter to a light source
(see Setting Reference Values on Your Power Meter on page 115), then
deactivate the light source.
4. If you have used a single reference patchcord, disconnect it from the
power meter port only, then attach a second reference patchcord to
the power meter.
OR
If you have used two reference patchcords, disconnect both of them at
the bulkhead.