Microcontroller implementation of digital fractional order controllers for time delay processes

The present work deals with the control of the liquid carbon monoxide level in a cryogenic carbon isotopes separation column. Due to the fact that the cryogenic carbon isotope separation column is a time and cost consuming process, the authors propose a hardware in the loop (HIL) simulation of the closed loop system prior to the actual implementation with, the controller being implemented on a NI PXI-8183 embedded controller from National Instruments and also on a MSP 430 Ultra-Low-Power microcontroller from Texas Instruments while the process is simulated using a personal computer. The designed controller is a PI fractional order controller and is implemented in a Smith-predictor structure, due to the process large time delays. The real time simulation results prove the efficiency of the controller, suggesting the possibility to use the implemented control structure on the real plant.