بسم الله الرحمن الرحيم Advanced Control Lecture three
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Transcript of بسم الله الرحمن الرحيم Advanced Control Lecture three
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Advanced ControlLecture threePID Controllers1- Action and types (Smith & Corripio: Chapter 5) 2- Reset windup (Smith & Corripio: Chapter 5) 3- Modifications (Smith & Corripio: Chapter 5 and Astrom & Hagglund: Chapter 3)1Lecturer: M. A. Fanaei Ferdowsi University of MashhadPID ControlAction of Controller: If the action is not correctly selected, the controller will not control
Reverse action (increase/decrease)
In feedback control loop, the multiplication of Process gain (Kp), Control valve gain (Kv), Sensor gain (Km) and Controller gain (Kc) must be positive.
Reverse action : If Kp Kv Km > 0 Kc > 0 2PID Control Direct action (increase/increase)
To determine the action of a controller, the engineer must know:The process characteristicsThe fail-safe action of the control valveDirect action : If Kp Kv Km < 0 Kc < 0 3PID ControlType of PID Controller
Classic PID:
Parallel PID:
Series PID:
Range :0.05 to 0.2(0.1)4
PID Control
5PID ControlReset Windup
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PID ControlReset Feedback (RFB)
Internal Reset FeedbackMminMmax
MmaxMmin
7PID ControlReset Feedback (RFB)
8PID ControlReset Feedback (RFB)
External Reset Feedback
9PID ControlBack Calculation
Back-Calculation with internal tracking
Tracking Time ConstantTd < Tt < TiInternal tracking signal
10PID ControlBack Calculation
Back-Calculation with external tracking
External tracking signal11PID ControlProportional and Derivative Kick
Proportional KickDerivative KickRange: 0-1Range: 0-1, Commonly zeroTwo Degrees of Freedom or ISA - PID12PID Control
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