S7-PLCSIM is an optional package for STEP 7 that allows simulation of a SIMATIC S7 control platform and testing of your user program on a PC. You can test and refine your project prior to physical hardware installation. By testing early in your project’s development you can improve overall project quality. Installation and commissioning will be quicker and less expensive as program faults can be detected and corrected early on during development. S7-PLCSIM includes the S7-ProSim interface that provides an ActiveX interface to any ActiveX enabled application, including dynamic process simulation packages.