DESIGN, FABRICATION AND TESTING OF A HUMAN MACHINE INTERFACE SCADA SYSTEM FOR PROCESS CONTROL

Abstract

The rapid adoption of the personal computer in the last 20 years catalyzed a revolution in instrumentation for test, measurement and automation. One major development resulting from the ubiquity of the computer is the concept of virtual instrumentation mainly referred to as SupervisoryControl and Data Acquisition (SCADA). The major attraction of such systems is the ability to significantly reduce operating labor costs, while at the same time improve plant system performance and reliability. However the use of obsolete technology and skills has crippled global competition among developing countries. In seeking solution,  a prototype of a SCADA system has been developed, the goal is to come up with an affordable, reliable and accurate Human Machine Interface (HMI) SCADA system. A lab view based HMI SCADA was developed and used on a fabricated heat exchanger prototype, in which the level and temperature of the system were the test parameters. The system was tested by issuing different set points for level/ temperature and measuring the response there after, the response was quantized by analyzing the characteristic waveform(s) obtained to determine the system response parameters (Rise time, steady state error, percentage overshoot and settling time), robustness and dead time. The system was found to have a better dynamic and static response characteristic compared to the commonly used embedded ON/OFF controllers, while the control algorithm simple to adopt.