Together with ENGEL, Austria in this project, LIT CPS Lab evaluates a new way to define the software architecture of PLC software. One of the approaches is applying the service bus concept from the enterprise domain to the PLC software. Software components of PLC software need to interact with each other to realize certain machine functionality. Current approaches utilize global variables, which increase the tight coupling among software components. Therefore, it is hard to adapt new customer requirements in the existing running production system. Enterprise domain also experienced similar issues by having such tight coupling between various applications. Enterprise service bus was introduced around two decades ago. Applications were using service bus to interact with each other and thus increases their flexibility and adaptability. In this project, first, we would like to evaluate the service bus concept for PLC software and find out a list of requirements such concept needs to fulfill. Later on, we would like to identify possible interaction patterns between software components to provide machine functionality. Finally, realizing this concept with a prototype solution.