A computer-based system to control drying and cleaning machinery selection in commercial gins was installed at Servico Gin in Courtland, AL, in 1994. This system is now the most complete computerized gin process control system in the world. Directional valves for seed cotton diversion were added in 1995, and a new color/trash measurement system was installed in 1996. This gin has operated with some of the process control components for three ginning seasons, including 40,500 bales in 1996. This paper describes the measurement components of the system and how they relate to the process control.