Testing with Your PPM-350B PON Power Meter
10
5 Testing with Your
PPM-350B PON Power
Meter
In this chapter, some instructions are identified as “Models measuring relative
power”. A quick way to confirm that your unit can measure relative power is to
verify if the keypad has a
button.
Nulling Electrical Offsets
Temperature and humidity variations affect the performance of electronic circuits
and optical detectors. Nulling the electrical offsets eliminates these effects.
Your unit
has been designed not to require offset nulling under normal operation
, but you
should perform it whenever environmental conditions change significantly or when
measuring very low power values.
Note:
Factory-defined values will be reinstated when you turn the unit off.
To perform an offset nulling:
³
[Models measuring relative power] Hold down
and
a few seconds.
³
[Other models] Hold down
and
a
few seconds.
The unit displays
NULL
and vertical bars move at
the top of the display, indicating the nulling is in progress.
Note:
Keypad is disabled during the operation.
The unit will then return to your previous mode (Pass/Fail or Normal).
I
MPORTANT
If light reaches the detector when nulling offsets, LIGH appears on
the display and the nulling is not performed. You will need to press a
key to return to the previous display.
dBm/
dB
dBm/
dB
REF/
SEL
Threshold
Select
