SMI++ — Object-oriented framework for designing control systems for HEP experiments Original Research Article

In order to cope with the complexity of the online control system, the DELPHI experiment at CERN (Aarnio et al., DELPHI Collaboration, Nucl. Instr. & Methods Phys. Res. A 303 (1991) 233–276) developed, in collaboration with the CERN OC group, a new concept for the coding of the control logic. In this concept — SMI, the State Management Interface (Barlow et al., IEEE Trans. Nucl. Sci. 36 (1989) 1549–1553) — the experiment is viewed as a collection of objects behaving as finite state machines. These objects are typically organized in hierarchical structures, allowing up to the full automation of the experiment by a a top-level object. This concept has been extended and is being redesigned using object-oriented techniques in SMI++ for the BaBar experiment at SLAC.