The concept of Digital Twins (DTs) can be utilized to solve complex problems in manufacturing based on the principle of Cyber-Physical Systems (CPS). While there are several reference architectures for CPS, there seems to be a knowledge gap between such high-level outlines and actual shopfloor-level implementations. This paper focuses on process control applications of the DT concept and proposes a specific implementation setup using fieldbus communication with a computer, aiming to fulfil a set of defined requirements. The setup is tested in an industrial use-case and the resulting characteristics of the solution are presented. A resulting assertion is that a DT of a process must be as specialized and customized as the system controlling it.