Process Simulation is the practice of creating a virtual reality for your PLC processor(s).
The virtual reality is developed to mock the real-life conditions of a process. This allows the programmer(s) to debug and modify critical SCADA applications with no down time. In addition to development, process simulation is also a useful training tool for new operators, or new processes.
CID utilizes Woodhead Industries "PICS" product. It is a very powerful tool that allows for efficient development, flexible connectivity, and senario configuration to easily create unique conditions for operator training.
To the right are a couple screen shots of the PICS development environment.