Portability in general open controllers

Openness is one of the features of modern open controllers. The porting ability of open control software is one of the most important aspects related to openness. In order to realize portability in future open control software, a thorough discussion about its conception is presented for a typical hierarchical control software architecture. A relative comparison of the three main corresponding programming language standards is presented because the realization of portability mostly depends on developing tools. The discussion and comparative results may be helpful to improve or preserve portability of future open control software.