Microprocessor-based control systems operator interface system

Initially, the microprocessor-based single-loop controllers made the power of digital control affordable to those with small processes. To compete with these products in small applications, the DCS suppliers have introduced micro-DCS versions of their products. As a PC-based operator interface is usually a component of the micro-DCS, there is sometimes little distinction between a micro-DCS and a system consisting of single-loop controllers coupled to a PC-based operator interface. 

When 8-bit microprocessor-based computers became available, we decided that such a computer, even though slower than minicomputers, would be adequate to operate the OMA and our interface controller with the ultracentrifuge. We now have in the system an Altair 8800 computer with 28K of memory (MITS, Albuquerque, NM), a hard-wired arithmetic board and two minifloppy disk drives (North Star, Berkeley, CA), a 700 ASR Terminal (Texas Instruments, Dallas, TX), and a 7202A Graphic Plotter (Hewlett-Packard, Palo Alto, CA). Appropriate software, written in Basic, has been developed to collect intensity data from the OMA automatically and also to treat and plot the data at the end of the experiment. Details of the system and software will be published elsewhere. We also have an improved illumination system with a 200 W Hg-Xe arc lamp and a Model H-20 monochromator with a holo-... 

Both the IE I C systems (Protection and Safety related monitoring) and the control systons (characterized by the absence of control rods and by the "hot-cold" interface regulation inside the Density Locks) are designed utilizing a proven, distributed microprocessor-based technology. An advanced control room, vrith a wall panel information station and work stations for operators and supervisor is foreseen, taking into account the most recent achievements and improvements in the man-machine interface systems. 

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