How to set a power reference on the Viavi Powerchek OP-1 power meter?
To set a reference on the Powerchek connect the light source directly to the Powerchek. Set the desired wavelength on the light source and turn the laser on. Source should be set for CW. Set the wavelength on the Powerchek by touching on the wavelength box until the correct wavelength shows. Set the scale selection for dBm by touching on that selection until it says dBm. Verify that you have a good dBm reading showing in the display. Press the capture button (large triangular hard button above the display) once. The power reading will freeze and show highlighted. Press and hold the REF selection until the unit beeps. It will switch automatically to the db scale and should read around 0 db. If there is no REF selection visible in the display touch in the bottom left corner to bring it up to the screen.