LPosvLPos.spt

Graphs | Data | Data Interpretation

The script graphs the commanded lens position verses actual lens position. This script is used to assess the position servo performance, stability, and range of motion.

LPosvLPos Graphs

LPosVLPos.ps: This graph shows actual lpos versus commanded lpos.

LPosvLPos Data

There is one output file, LPosVLPos_data.txt, containing three columns:

1. Commanded LPos, in microns.
2. Actual LPos, in microns.
3. This column contains no useful data.

Interpretation of the Data

It is necessary for the focus servo to track the commanded input very accurately, to around 0.5um. If there is any ringing in the graph, or any audible ringing heard during the running of the script, then the servo parameters should be re-tuned using the CurrentPing.spt and ForcePing.spt scripts. The actual lens position will tend not to exceed roughly +/-200um, since the hall sensor will saturate at these extremities.