A broad range of man-machine interface (MMI) functions is critical to the effectiveness of a distributed microcomputer-based process control system (DCS). This broad range is dictated by the vastly different requirements of the people who must interface effectively with the DCS. The functionality of personal computers (PCs) has precipitated a new era of distributed man-machine interfaces. A commercially available PC can now be transformed into a control system engineering tool, an operations monitoring and reporting device, or a small-system operator interface. Bailey Controls has structured its INFI 90 product line to include a fully integrated family of MMI devices.