Principle of cross-limiting control and materials required for DCS configuration
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I need help understanding the principle of cross-limiting control, as well as what kind of schematic diagrams are required to assist DCS configuration engineers in implementing this control. I work in a design firm; thank you!
In some control requirements, in order to meet a certain control target, several process variables need to increase or decrease together, with the difference between each variable not exceeding a predetermined value; this is known as cross-limiting. A typical application is the addition of air and coal in boiler combustion: any increase or decrease in either must be done in coordination, at the optimal ratios specified in the design, in order to achieve complete combustion. Typically, it is necessary to provide 1 the static ratio between process variables and 2 the maximum deviation limit based on that ratio