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 Supervisory
Control 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.
