BBSprofile.spt

Graphs | Data | Data Interpretation

This script measures the profile of the write laser beam with the beam balance sensor (BBS). The output of this script helps to show how difficult the write laser beam will be to balance.

Your system must be properly configured before running this script. See Note 1 for more information.

BBSprofile Graphs

1. BBSProfileAll.ps contains three elements:
   1. Write laser profile with zero attenuation
   2. Write laser profile with half (127) attenuation
   3. Write laser profile with full (255) attenuation
2. Ratio.ps is a plot of elements c over a from the BBSProfileAll.ps graph.

BBSProfile Data

There is one output file, BBSProfile_data.txt. This file contains five columns:

1. Pixel number
2. Write laser reading, zero attenuation
3. Write laser reading, half attenuation
4. Write laser reading, full attenuation
5. Ratio of full attenuation over zero attenuation

If the stroke width is less than 240, the write laser readings and the ratio for unused pixels are set to zero.

Interpretation of the Data

A successfully balanced beam will have a flat profile on plate. In order to achieved this, the highest point of the full attenuation graph must be higher than the lowest point of the zero attenuation graph. You should have a large buffer between these two points, as this will allow for changes due to aging of the write laser and light valve. If the slope and curve are non-zero the final balanced profile will not be a straight horizontal line. This may end up using some of the buffer available for the aging of the laser.

Note: The final balanced profile does not need to be a straight horizontal line.