Closed Loop Control System


Closed Loop Control System 

Closed loop control system is defined as feedback control system. Closed loop control system is almost identical to open loop control system except it has at least one feedback loop from output to input.

Figure 1: Schematic diagrams of closed loop and open loop
            Feedback loop is used to monitor the output and feedback to input. Thus, inaccuracy at output can be corrected and desired output can obtained. Therefore, the output of closed loop control system is more accurate than open loop control system but more expensive and difficult to design. The main advantages of closed loop system are wider bandwidth, output error can be detect, reliable and accurate output.

Examples of closed loop system are air conditioner, automatic electric iron, water level controller and servo voltage stabilizer. For air conditioner, fans speed and heats exchange rate of condenser and evaporator depend on room temperature. Next, water level controllers vary the input water rate by monitor the water level of reservoir.

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