Modularization of process plants is seen as one approach to face the increasing flexibility requirements in the process industry. Therefore, modules are combined to a modular process plant to achieve a higher flexibility of the production. Conventional distributed control systems do not support flexible production systems adequately. Hence, modules should encapsulate process functions as services. The services should be invoked and controlled by state-based control. This contribution presents an approach for the state-based control of services, following a defined state-model. The approach has been tested in two case studies and two different implementations: In a simulation environment based on Matlab Simulink Stateflow, and in an industrial implementation of a pump and a controller. This contribution provides an overview of the developed concepts and their capability for the use in industrial environments.