Saeed Nadi - Department of Chem. Eng., Faculty of Eng., Ferdowsi University of Mashhad, I.R. Iran
Mohammad Ali Fanaei - Department of Chem. Eng., Faculty of Eng., Ferdowsi University of Mashhad, I.R. Iran
Hojjat Dehghani - Department of Chem. Eng., Faculty of Eng., Ferdowsi University of Mashhad, I.R. Iran

Relative gain array (RGA) method is the popular technique to delineate the control loop pairing by just applying steady state gain. Recently, new loop pairing criterions; relative effective gain array (REGA) and relative normalized gain array (RNGA), are proposed which employed both steadystate gain and transient information of the process transfer function. In this paper, several examples are used to evident the effectiveness of these methods. The results show that RNGA loop pairing criterion provides accurate interaction assessment whereas RGA and REGA may give inaccurate results.

Multiloop Control, Loop pairing criterion, RGA, REGA, RNGA