Process Control: Learning It and Doing It Through LabVIEW Based Design

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1 Process Control: Learning It and Doing It Through LabVIEW Based Design Heidi B. Martin and R. Craig Virnelson Chemical & Biomolecular Engineering Dept. Case Western Reserve University

2 Our Process Control Class

3 Approach Reliance on LabVIEW and data acquisition as userfriendly tools for the integration of concepts in controller modeling and implementation Motivation Traditional Process Control courses focus mostly on process control theory

4 Our Reinvented Course Recitation Time Switched to Lab Session (Overall Course is 4 Credit Hours) Heavy Use of LabVIEW for both Data Acquisition and Process Modeling Training in LabVIEW, Data Acquisition Design Project Couples Modeling & Implementation Ongoing Emphasis - Connection Between Theory & Practice (Process Modeling, Transfer Functions, Linear Feedback Control Theory, Feedforward & Cascade Control)

5 Coupling Data Acquisition with Feedback Control LabVIEW software - Graphical Programming, User Friendly Data Acquisition Teaching Platform (National Instruments NI-ELVIS II) Custom Built Data Acquisition Platform (Uses NI board) Supply Room Project Equipment

6 Early Incorporation of LabVIEW WEEK OF THE SEMESTER DESIGN PROJECT ACTIVITY Preliminary Project Proposal Submission LABVIEW TRAINING/ASSIGNMENTS For Data Acquisition In class Tutorials Training Programs 1-3* Analog Inputs Control Lab, Part 1 Control Lab, Part 2 For Modeling Introduction to the Simulator Process Simulations 6 Team Meeting Time Domain with Instructor Non-Linear Systems Training Programs 4-7* 7 Analog & Digital Final Project Process Simulations: Inputs & Outputs Proposal Transfer 8 Description Functions with Gantt Chart Linearization 9 Relating Transfer 10 Written Training Program 8 Functions to Status Report 1 PID Control Instrumentation 11 Closed Loop System 12 Simulations: Design Project VI s Feedback Control 13 Written Preliminary Hardware VI System Stability Status Report 2 Preliminary Simulation of Feedforward & Process Cascade Control

7 Stage 1: Predetermined Project ph Control Design Program Tune Controller Non-Linear System Less Creativity

8 Stage 2: Student-Selected Topics Top Project 2012 Guitar String Tuner Pancake Producers Baby Rocker-for Restful Sleep Venetian Blinds Dissolved CO 2 in Aquariums Solar Panel- Rotation & Tilt Smart Umbrella Ballast Tanks Waterline of Ships

9 Stage 3: Team Projects Hydroponics (ph & T Control) Public Demo Session Violin Tuning (3-D Printing of Peg Clamp) Drink Composition (Switch Valves- Integrate Flow) Sugar Content (Auger) Reaction Yield (Conductivity)

10 Simulation & Modeling with LabVIEW Tank 1:,1 1 1 Tank 2:,1, , , R valve resistance; R1 R2 0.5 A tank cross sectional area; A1 A2 1 h tank level Based on Example 4.4, Seborg et al., Process Dynamics & Control

11 Step Tests & Transfer Functions Step Test ( ph)* Tau 63% of Step Response Tau Fit to First Order Model 4 to to to to to to ph Time (sec)

12 Survey Students from Past 5 Years Avg. 42% Response Rate All Student- Selected Projects Level of Interest in Design Project (Pre-built) ph control = Lower Interest

13 Project Difficulty Worth the Effort Most felt Somewhat Difficult Level of Difficulty of Design Project (Pre-built) ph control = Somewhat or Very Easy

14 LabVIEW Motivated Interest in Control Blue = Higher Red = Unchanged Green = Lower

15 Students Gained Confidence Blue = Substantial Red = Modest Green = No Change (Pre-built) ph control = Higher percentage felt confidence unchanged

16 Impact throughout Curriculum Research, Internships and Co-ops Chemical Process Control (Junior Year) Measurements Lab (Junior Year) Students Design Experiments & Systems to Solve Problems Senior Design Projects

17 Process Control is Fun & Relevant Bridge Gap between Theory and Reality Provide Design Project Experience Train with a New Skill Set to Address Design Problems Acknowledgments Chemical & Biomolecular Engineering Dept. William James (BS, Case 1964) Students of ECHE 367, Process Control