A continuous process operates 24/7, with raw materials constantly fed into the system and finished products continuously discharged. The goal is to maintain a stable, steady-state operation at an economically optimal setpoint. include high volume, efficient energy use, consistent product quality, and complex, highly automated control systems to manage dynamic interactions (e.g., oil refineries). Control objectives focus on maintaining stability, rejecting disturbances, optimizing efficiency, and preventing off-spec product. Common strategies include PID control, feedforward control, cascade control, and Model Predictive Control (MPC).
Table of contents * Acknowledgments. * About the Authors. * Foreword. * 1 Introduction. * 2 Background and Historical Perspective. control loop foundation batch and continuous processes pdf
| Component | Function | Example | | :--- | :--- | :--- | | | The parameter being measured | Temperature (°C), Pressure (psi), Level (%) | | Setpoint (SP) | The desired target value for the PV | 150°C, 50% tank level | | Sensor/Transmitter | Measures PV and converts to a standard signal (4-20 mA, digital) | Thermocouple, pressure transducer | | Controller | Compares PV to SP, calculates error (E = SP - PV) | PLC, DCS, PID controller | | Final Control Element | Acts to change the process | Control valve, variable frequency drive (VFD), heater | A continuous process operates 24/7, with raw materials
Measures the Process Variable (PV) and converts it into an electrical or digital signal (e.g., 4-20 mA, Foundation Fieldbus, or WirelessHART). * About the Authors
The value of "Control Loop Foundation" is fully realized in its practical application examples. These are not just theoretical exercises but are based on the authors' personal experience working with process control systems in industrial environments. For both continuous and batch processes, the book provides case studies that illustrate how to combine basic control techniques to meet complex requirements. A few examples include:
Reacts to the accumulation of past errors (eliminates offset).