In this article the so-called servomechanism problem is solved. This is one of the most basic p roblems in the field of automatic control, and it arises in almost every application problem of the process industry. In the servomechanism problem, it is desired to design a contro ller for a plant so that plant outputs are independ ent, as much as possible, from disturbances which may affect the system (i.e. regulation occurs), and also the outp uts asymptotically track any specified reference input signa l applied to the system (i.e. tracking occurs), sub ject to the requirements of maintaining closed-loop system stabil ity. The complete controller is formed by a plant s tabilizer, a decoupling network and PI channel compensators. It is showed the applicability of the approach means o f the control of a distillation column.