Need to perform a zero calibration, and the black trap is not available. Although it is recommended to use the black trap when performing the black calibration, an open port measurement may be used if the following steps are performed:
1. When the software prompts, pull the sample holder arm back to its full extent to ensure that any part of the assembly is not in the measurement path.
2. Ensure the measurement path in front of the unit is clear for at least 1 meter.
3. Ensure that there are no mirrors, windows, ambient light or other “shiny” objects in the direction of the unit’s viewport.
4. Stand to the side of the unit.
5. Click “OK” in the software. The unit will flash and the black calibration is complete.