Control system design is a crucial point in modern automation systems, involving an increasingly broader set of activities being performed by software. Despite the availability of several domain-specific facilities, designers daily face kindred issues which actually lack reference patterns, in particular as regards the architectural organization of the control logic. In this paper we present an approach that, focusing on crosscutting domain problems and suitably abstracting from application-specific details, leads to an effective decoupling of high-level control policies from low-level actuation and sensing mechanisms. Logic Device Agents emerge as generally applicable active components modeling the behavior of commonly used field devices, which can be profitably exploited to enhance software design quality and productivity