SOAP4PLC: Web Services for Programmable Logic Controllers

The use of service-oriented architectures based on web services in the manufacturing layer of industrial enterprises yields vertical integration and promises increased interoperability and flexibility. Unfortunately, two main obstacles complicate the use of web services in the manufacturing layer. First, the hardware/software used in this layer differs from the hardware/software used in other layers. Second, the manufacturing layer is maintained by automation engineers who typically are not familiar with web services. This paper presents the first SOAP engine for programmable logic controllers to advance the use of web services in the manufacturing layer. The engine offers a low memory footprint to respect the low computational power of programmable logic controllers and allows to export web services automatically without intervention of an automation engineer.