PH Loop
PH control is a difficult problem due to the highly non-linear nature of the system. The steep slope of the titration curve around the pH = 7 point amplifies pH variations for even small base/acid addition variations. The pH control rig in the PMC lab illustrates that pH control is by no means impossible (albeit on a laboratory scale).
Contents
Current/Previous projects
1999
F.J. Botha, Ondersoek van die Dinamiese Gedrag van Sisteme waar pH Gemeet en Beheer word {Investigation of the Dynamic Behaviour of Systems where pH is Measured and Controlled}
[Hard copy of report available in pH rig folder]
2003
T. Leeuw & G. Mascini, pH Rig 2003 - CPL780 Process Control Laboratory
Report | Project files
2005
A.J. Swanepoel & M. Swanepoel (Botha), Model Based Control Laboratory, pH Control
Report | Project files
2007
C. Steyn, Fuzzy Logic Rule-Based Controller Design, Neutralization of Strong Acid with Strong Base
Report | Project files
2009
A.H. Campher, Maintenance, Modelling and Control of the pH-control Rig
Report | Project files
2010
A.B. De Jongh, Control of a pH neutralisation system using Gain Scheduling
Report |
Project files
2011
S.C. Burd, Non-Linear Model Predictive Control of a pH Neutralization Process
Report |
Project files
Documentation
Large scale renaming of instruments, valves and tanks is being done. This renders all previous rig diagrams obsolete. Only 2009-updated diagrams should henceforth be used.
Piping & Instrumentation diagrams
Wiring diagrams
Connecting the pH rig to the OPTO22 system
The attachment gives details about operating the pH rig from the Simulink environment and connecting it to the OPTO22 system. Document
Rig maintenance
The maintenance of the pH rig is documented here.
