EXFO PM-1600 High-Speed Power Meter - Manual (Page 22)

Getting Started with Your High-Speed Power Meter
12 PM-1600
Nulling Electrical Offsets
2. If necessary, select the desired channel (in the case of a PM-1620) by
pressing Chan. In the above figure, channel #1 is currently selected.
3. Press Shift, then Null. The offset nulling process takes approximately
10 seconds. Once done, the unit returns to the previously active
operation state.
Note: If you are trying to perform an offset nulling with a protective cap
improperly tightened on the detector port, the message Light detected will
be briefly displayed. If so, ensure the protective cap is properly tightened
and restart the offset nulling.
Note: Offset nulling constants are retained until a new offset nulling is performed.
Getting Started with Your High-Speed Power Meter
12 PM-1600
Nulling Electrical Offsets
2. If necessary, select the desired channel (in the case of a PM-1620) by
pressing Chan. In the above figure, channel #1 is currently selected.
3. Press Shift, then Null. The offset nulling process takes approximately
10 seconds. Once done, the unit returns to the previously active
operation state.
Note: If you are trying to perform an offset nulling with a protective cap
improperly tightened on the detector port, the message Light detected will
be briefly displayed. If so, ensure the protective cap is properly tightened
and restart the offset nulling.
Note: Offset nulling constants are retained until a new offset nulling is performed.