TANGO is an object oriented control system for Linux and Windows. It provides a framework in C++, Java and Python for implementing distributed control objects an accessing them via a well-defined API.
This sourceforge project a
RTS2 is project to create an open source environment for control of a fully autonomous observatory. It is running about dozen fully autonomous observatories. Its modular design allow easily addition of new devices (to already huge supported HW list).
DAVIC (Distributed Automation Via Implicit Channels): A simulation platform for doing research on wide-area automation problems like the electricity grid, based on OMNet++