After a detailed study of the PS complex requirements by experts of the CERN controls & operation groups, a proposal to develop a new system, called Injectors Control Architecture (InCA), was presented to and accepted by the management late 2007. Aiming at the homogenisation of the controls systems across CERN accelerators, InCA is based on components developed for Large Hadron Collider (LHC) but also the new components required to fulfill operation needs. In 2008, the project was in its elaboration phase and we successfully validated its architecture and critical use-cases during several machine development sessions. After a minute description of the architecture put in place and the components used, this paper will describe the planning approach taken combining iterative development phases with deployment in operation for validation sessions.