In full stimulation, the simulator uses all Distributed Control System (DCS) vendor equipment, similar to that used at the site, including the distributed processors (i.e. MFPs, DPUs, or CPs), the data highway (i.e. INFINET, WESTNET, or NODEBUS), and the operator terminals (i.e. OIS-42, WEStation, or AW-51). The control algorithms execute in the actual distributed processors and the actual graphics execute on the operator terminals or man-machine-interface (MMI). The term "full" is used because both the MMI and DCS processors are stimulated by the master workstation.

Partial Stimulation

In partial stimulation, the simulator uses part of the DCS vendor equipment used at the site. This type uses the same MMI hardware and data highway as for full stimulation but a translated version of the control algorithms (these are not the actual algorithms) are used on the Master workstation instead of the DCS processors. We have developed translators for two of the major DCS suppliers: Bailey and Westinghouse. These translators accept a file from the engineering workstation of the DCS and create a complete representation of all control structures and connections. The term "partial" is used because only the MMI is stimulated.

Virtual Stimulation

In virtual stimulation, the simulator uses part of the DCS vendor equipment that is used at the site. This type uses the actual control algorithm software as in full stimulation, but it executes directly on the Master workstation instead of on the DCS processors. The MMI is the same as in the full stimulation case. The term "virtual" is used because the DCS processors are replaced with another processor, namely the one in the Master workstation.

Emulation

This type of simulator typically does not use any part of the DCS vendor equipment. It uses both graphical and controls configuration translators to simulate the graphic displays and controller algorithms. The DCS vendor MMI is simulated on personal computers or workstations. This type of design is seldom used any more, due to high maintenance costs both for customers and simulator suppliers.