Fluke FTK200 - Setting a Reference for Loss Measurements; When to Set Reference; Reference Setting Procedure

FTK200
Users Guide
10
Setting a Reference for Loss
Measurements
Setting a reference lets the meter automatically subtract
from loss measurements the losses due to patch cords.
The loss for a fiber under test is automatically calculated
as the difference between the reference loss and the loss
with the fiber inserted.
For the most accurate test results, you should set the
reference at these times:
• Anytime you start using a different optical source for
loss measurements
• Anytime you change the patch cord used on the
meter or source.
Note
For the most accurate test results, set the
reference at the beginning of each day using the
patch cords and wavelength settings you will use
for testing.
The meter stores a separate reference value for each
wavelength. The reference values are not affected when
you turn the meter off or change the battery.
To view the reference for the selected wavelength, press
r
briefly.
To set a reference, proceed as follows:
1. Set the source to the wavelength you will use for
testing. Let the source warm up for two minutes.
2. Select two known-good patch cords of the same type
as the fiber to be tested. Select one known-good
adapter of the appropriate type. Clean all fiber ends.
3. Make the connections shown in Figure 6. Turn on the
meter. Press
N
to select the proper wavelength.
Normally, the reading will be about -20 dBm. If the
reading is too low, check the source connections and
wavelength, or clean the fiber ends again, or select
different patch cords, or use a different adapter.
4. To set the reference, hold down
r until HELD
appears on the display. The loss reading should then
change to 0 dB. The last digit may vary slightly
because of fiber movement and minor variations in
the output power of the source.
5. If you are testing with more than one wavelength,
change the meter and source to the new wavelength,
then repeat step 4.