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Control Systems OverviewA control system is a device or set of devices that manage and regulate the behavior of other devices to achieve desired results.Linear SystemsLinear control systems adhere to principles of homogeneity and additivity, ensuring consistent and proportional responses.Non-Linear SystemsNon-linear control systems do not follow linear rules, often resulting in behavior that varies significantly with different inputs.Digital vs AnalogDigital systems provide improved accuracy, re

Bidirectional Thyristor Temperature Control Circuit

Simple temperature controller circuit

What is a Control System?Control System DefinitionA control system is defined as a system of devices that manages, commands, directs, or regulates the behavior of other devices or systems to achieve a desired result. A control system achieves this through control loops, which are a process designed to maintain a process variable at a desired set point.Components of the control system Controller Controlled object Executive mechanism TransmitterFeatures of a Control SystemExplicit mathematical rel

What is an On-Off Controller?On-Off Controller DefinitionAn on-off controller is defined as a control system that fully opens or closes the control element when the process variable crosses a preset level.Working PrincipleThe on-off controller works by fully opening or closing the output value, causing the process variable to change direction and cycle continuously.Example of ApplicationA typical example is the cooling fan control in transformers, which activates based on temperature levels.Actu

What is Control Engineering?Control Engineering DefinedControl engineering is the field of engineering that focuses on designing and optimizing systems to function in a desired, controlled manner using principles of control theory.Classical vs. ModernClassical control engineering uses transformed equations to analyze Single Input Single Output systems, while modern control tackles complex systems with state-space and vector methods.Historical SignificanceThe history of control engineering showca

What is Nyquist Criteria ?Nyquist Stability Criterion DefinitionThe Nyquist stability criterion is defined as a graphical technique used in control engineering to determine the stability of a dynamical system.Application of Nyquist CriterionIt applies to open-loop systems and can handle transfer functions with singularities, unlike Bode plots.Criterion FormulaZ = number of roots of 1+G(s)H(s) in right-hand side (RHS) of s-plane (It is also called zeros of characteristics equation)N = number of e

What is a SCADA System?SCADA DefinitionSCADA is defined as Supervisory Control and Data Acquisition, a system used for high-level process control and data management.Component Master Terminal Unit (MTU) Remote Terminal Unit (RTU) Communication Network (defined by its network topology)Functions To monitor and gather data in real-time To interact with field devices and control stations via Human Machine Interface (HMI), To record systems events into a log file To control the manufacturing processe

What is Steady State Error?Steady State Error DefinedSteady state error is the discrepancy between a control system’s desired and actual output values once the output has stabilized.Influence of Input TypesThe size of the steady state error varies with different types of inputs—zero for step inputs, a constant for ramp inputs, and infinite for parabolic inputs.System StabilityUnlike steady state error, the stability of a control system does not depend on the type of input but on the system’s tra

What is a Transfer Function?DC Gain DefinitionDC gain is the ratio of the steady-state output to the steady-state input of a control system when given a step input.Transfer FunctionA transfer function represents the relationship between a control system’s input and output using the Laplace transform.Final Value TheoremThe final value theorem helps find the DC gain by evaluating the transfer function at zero for continuous systems.Continuous vs. Discrete SystemsDC gain calculations differ between