Category: Control Systems
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How to Effectively Design Control Systems for Distillation Units
A distillation unit is an industrial apparatus used to separate impurities and products of a component based on their boiling point. The distillation process is managed by a control system to ensure optimal operation of the unit.The aim of the control system for a distillation unit is to manage the operations of the distillation process.…
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Process Control System Design for a Distillation Unit
The aim of a typical control system is to force a given set of process variables to act in some desired and prescribed way by either fulfilling some requirements of the time or frequency domain or achieving the best performances as expressed by an optimization index. The scope of the control tasks varies widely. The…
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Three-Position Control System: Operation & Typical Application
A three-position control is akin to two-point control, except that in this case, the controller has three states, such as forward-off-reverse, (or up-off-down, hot-off-cold, etc.). This is a control strategy that is usually applied in a system that has no specific self-seeking rest state. To help us demonstrate this control strategy, take a case of…
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How Cascade Control System Enhances Dynamic Response to Load Changes
The major limitation of a conventional feedback control system is that the correction for disturbances does not start until the process output deviates from the setpoint. Feedforward control provides big improvements in processes with large time constraints or time delays. But, feedforward control requires that the disturbances be measured explicitly and a model must be…
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What is Optimal Control?
Optimal control is whereby the requirements are formulated as either the minimization of a cost index or the maximization of a performance index of an operational control system. Optimal control is utilized in a number of disciplines such as aircraft and spacecraft, satellites and aerospace, communications engineering, robots and robotics, electric drives, power systems, computer…
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Phase Locked Loop High Precision Motor Speed Control System
AC generators can be utilized in high precision control systems. The AC generator rotor is rotated by the rotating shaft (i.e. the shaft from the motor being controlled). The output AC frequency is proportional to shaft speed. Zero crossings per time interval can be counted to determine speed for a simple control system. If high…
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Safety Function in a Machine Control System
A safety function is executed by the safety-related parts of the machine control system to achieve or maintain the equipment under control in a safe state with respect to a specific hazard. A failure of the safety function can result in an immediate increase of the risks of using the equipment; that is, a hazardous…
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Basic Features of Cascade Control
A cascade control system typically consists of a primary or master controller that generates a control function that serves as the setpoint for a secondary or slave controller. That controller in turn utilizes the actuator to apply its control function directly to the secondary process. The secondary process then generates a secondary process variable that…
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The Goals of Robust Control Techniques
Robust control is normally used to handle systems with uncertainties & disturbances and with high performances. The objective of robust control is to be able to design controllers that achieve a desired level of performance and also, be able to handle a collection of uncertainty structures specified by the designer. A typical approach is to…