Santec PEM-320, Operation Manual

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7-4
PEM-320 Operation Manual
7.3. Offset Cancel
The Offset Cancel function enables compensation of the dark current of the photodetector. The
PEM-320 can be used directly after the power has been switched on and the initialization
procedure has completed. However, to ensure high accuracy, it is recommended that the unit is
allowed at least five minutes to warm up before any measurements are taken. After the unit has
warmed up, ensure the cover is on the optical input connector so that no light enters the
instrument and press the Zero Key to perform the Offset Cancel.
7.8. Changing Display Units
The Power Display Panel can display the optical power in either mW or dBm. The display is
toggled by pressing the Optical Power Unit Selector Key.
7.4. Changing Display Units
7.8. Changing Display Units
In normal operation the PEM-320 outputs a value for PER for each 360˚ rotation of the polarizer.
This is the averaged value of two measurement cycles. The PER Averaging Function enables
this averaging function to be turned on or off. The command is only available through the
communication interfaces using the AO and AF commands (see Chapter 8 for details).
7.5. PER Averaging Function