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Engineering LibreTexts

11: Control Architectures

  • Page ID
    • 11.1: Feedback Control
    • 11.2: Feed Forward Control
      Feed-forward control is a useful tool when there is a known set of deviations occurring upstream of the system. This would allow engineers to account for that particular deviation within the controller and reduce the effects of the deviation on the system. An example would be a car's cruise-control system. If it has feedback control, when there is a slope and therefore a speed reduction, the feedback controller would compensate by applying additional throttle to the engine.
    • 11.3: Cascade Control
    • 11.4: Ratio Control
      Ratio control architecture is used to maintain the relationship between two variables to control a third variable. Perhaps a more direct description in the context of this class is this: Ratio control architecture is used to maintain the flow rate of one (dependent controlled feed) stream in a process at a defined or specified proportion relative to that of another (independent wild feed stream) in order to control the composition of a resultant mixture.
    • 11.5: Common control loops and model for liquid pressure and liquid level
    • 11.6: Common Control Loops and Model for Temperature Control
    • 11.7: Common control architectures and model for reactors
      Reactors are the central focus of many chemical plants. It is important to design an effective control architecture in order to ensure optimal operation of the reactor. This article discusses the common control architectures and topologies in CSTRs. The control architectures are designed based on whether the reactor is endothermic or exothermic. The same concepts introduced in the wiki can be applied to other reactors as well. However, only CSTRs will be discussed for simplicity.