Maintain80 - Example CoRE Piston To Keep Light Levels at 80%
This example will demonstrate how to maintain all lights at a specific level even if a person turn on or raises the level above the maximum which in our example is 80.
The hardest trick to this piston was figuring out how to break up the statements and where to trigger the level change so that it would not affect the other lights. I would suggest you also put another condition of time on this to check every 5 minutes as without it, the continuous calls to see which lights are off could get expensive.
1 or more bulbs
Before starting, set for expert mode: Settings->ExpertFeatures turn ON Expert Mode
Piston Mode: Basic
You will note this will only affect lights that are on by using the call to Set Level Advanced.