EXFO IQS-1500 Power Meters for IQS-500/600 - Manual (Page 38)

Preparing Your Power Meters for a Test
30 IQS-1100/IQS-1500
Nulling Offsets
Nulling Offsets
Temperature and humidity variations affect the performance of electronic
circuits and optical detectors, which can offset measurement results. To
compensate for this offset, the unit is equipped with an offset nulling
function.
Your unit is 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.
Your IQS-1100/IQS-1500 Power Meters automatically performs nulling of the
offset each time you turn it on.
However, you might need to perform a manual nulling of the offset when
environmental conditions change significantly or when you are measuring
very low power.
Note: The manual nulling offset is valid for the current test session only; it no
longer applies when you turn off your power meter. The next time you turn
it on, the automatic offset nulling is performed again. You will achieve
better results if you perform the manual offset nulling at a temperature
around 23
o
C after a running period of 45 minutes.
I
MPORTANT
To obtain optimal results with your IQS-1500 Calibration Power
Meter, always use the FOA and patchcord included with the unit.
I
MPORTANT
Light must not reach the detector when performing an offset
nulling operation. Always use a protective screw cap. Do not use a
soft rubber cover