The basic idea of Soft-Commissioning (SoftCom) is to test industrial control software by connecting a controller, e. g. a PLC (Programmable Logic Controller) to a commercial discrete event simulator (DES), which provides system reactions and sensor signals similar to the behavior of real hardware, e. g. an industrial manufacturing line. In order to establish a connection between simulator and PLC, a modular architecture was developed. The basis of this modular system is a communication protocol common to all members. The two basic modules are the I/O Devices Driver (IODD), which is used to interface between the I/O hardware and the SoftCom protocol, and the Simulator to real World Interface (SWI). The SWI is used to link the simulator to the SoftCom system.