This is from the _TUNE example in SIMION 7.0. From the README file:
The files in this directory provide an example of having user programs tune a lens. It serves as a moderately complex control problem and should be studied for tricks of the trade.
A simple three element fast adjust lens is provided for tuning The middle electrode is adjusted via user program tune.iob (Lens tuning demonstration file). This should serve as a simple example of how tuning problems might be approached.
Auto-tune of middle electrode voltage via a user program.