I started with distributed systems (did the parking system and network of parking revenue control at Richmond Airport) which includes lots of rs 422, 485, and 232, as well as the obvious ethernet interconnecting and multi-mode fiber. I wrote most of the database that collects station, device, and revenue data. I moved from that into industrial machine automation, doing the PLC programming, touch-screen machine interfaces, and DB/historical data collection. I did some process engineering as well. For the past few years I have been working on the electrical side, concept, and programming for industrail robotic work cells (so all of it, PLC and interface programming and communications), though the focus is the whole machine and not solely the robot(s). I haven't done HVAC controls design, but understand the systems and devices that are used. I have about 8 years experience in this field. Post or PM me your email and I'd be glad to forward a resume.