I used to be a senior .NET developer until I returned to being a DCS engineer.
I am currently deployed at Invensys Operations Management within Region 5, Northern Europe (based in the Netherlands).
Foxboro I/A is one of the oldest true OOP systems. It has been around since the 80's and is now becoming more and more integrated with other Invensys systems like for instance Intouch (Wonderware). We do use .NET for our Advanced Applications. Come have a look at our web-site, and find out how much fun there is in Industrial Automation...