An Internet-Mediated Process Control Laboratory By Deepak Srinivasagupta and Babu Joseph A lthough realistic simulations can provide valuable experience for the student learning control theory, the importance of actual laboratory experiments cannot be overestimated. Real experiments bring with them valuable lessons on the effects of noise, control constraints, nonlinear effects, and time-varying parameters on control system performance. Visual feedback is also important. Due to a variety of factors, however, sometimes it is difficult to provide this experience in a traditional course. This article presents an alternative way to provide such experience us- ing a different delivery mechanism. Two laboratory-scale experiments have been developed that can be executed safely over the Internet. Remote ac- cess is within a client-server paradigm. Servers connected to the processes through the usual data acquisition hard- ware address issues regarding safety, security, data valida- tion, and session management. A unique feature of the lab is the ability for the student to design, test, and verify control strategies in real time over the Internet. Necessary inter- locks and cutoffs ensure safe remote operation of the units. Studies have shown that network speeds are not a signifi- cant concern for these systems due to slow process dynam- ics. The availability of Internet- mediated laboratory modules on an anytime/anywhere basis will enable a larger fraction of the class to get valu- able laboratory experience. These ex- periments have also been used in an Internet-wired classroom for interac- tive demonstrations during lecture. A real-time Internet-mediated labo- ratory has several useful pedagogic features. The teacher can assign labo- ratory exercises as homework; the lab- oratory can be run any time from anywhere. As network bandwidth in- creases in the future with the wide- spread availability of broadband, this laboratory can be extended to provide live video and audio transmission and can serve as a useful classroom tool and facilitate distance learning. So far, most of the initiatives on Web-based education have been restricted to course content delivery and testing (see [1]-[3]) or virtual laboratories [4]. There have been relatively few real-time laboratories (see [5]) (and even fewer process control labo- ratories) accessible over the Internet due to concerns about bandwidth requirements, quality of network service, ro- bustness, safety, and security. The real-time laboratories of- ten rely on proprietary solutions and tend to be somewhat inflexible. Our objective is to address some of these con- cerns and help others who are engaged in similar efforts. Most universities today have reliable broadband connec- tions so that real-time Internet-mediated control is feasible. Such a facility will also allow expensive physical hardware to be shared among different institutions and permit collab- orative teaching and research [6]. Advances in networking and improving hardware speeds have led to increasing re- search in real-time control over the Internet [7], [8]. The University of Tennessee at Chattanooga has an on- line process control laboratory at http://chem.engr.utc. edu [9]. This facility allows parameter changes to the con- troller from a fixed client interface. The implementations described in this article are based on the client-server par- adigm whereby the client is a MATLAB/Simulink interface February 2003 IEEE Control Systems Magazine 11 EYE ED U CATI O N on 0272-1708/03/$17.00©2003IEEE Cold Water Flow Rate AO_0 DO_0 Cold HV-1 DO_1 HV-2 Electric Heater To Drain Tubular Heat Exchanger To Drain Heater Power AO_1 FT  AI_5 TT  AI_0 FT  AI_6 TT  AI_4 TT  AI_1 TT  AI_3 TT  AI_2 Figure 1. Instrumentation diagram of heat exchanger experiment. Joseph (joseph@eng.usf.edu) is with the Department of Chemical Engineering, University of South Florida, Tampa, FL 33620, U.S.A. Srinivasagupta is with the Process Control Systems Laboratory, Department of Chemical Engineering, Washington University, St. Louis, MO 63130, U.S.A. Authorized licensed use limited to: University of Michigan Library. Downloaded on April 09,2010 at 18:09:57 UTC from IEEE Xplore. Restrictions apply.