A simple display-interactive system for process control using a small computer is presented which is based on conventional digital filter design methods and accuracy considerations. The system permits gain, lead, and lag-lead compensation of a two-real-pole plant with position offset. The program, written for the PDP-12, allows the user much flexibility in sampling and displaying the step, responses and choosing the compensator parameters. There is also provision for evaluating the system performance (peak time, maximum overshoot, and position offset). This flexibility is provided by organization of the program into large subroutine packages, e.g. graphic display, fixed-point two-decimal-place and double-precision (24-bit) fractional arithmetic routines, compensator difference equations, etc. Discussed are theoretical and practical aspects of the system design and implementation, sources of error, overall structure of the program, including a general flowchart, experimental results, the limits imposed on the program by the computing facilities used, and some suggestions concerning possible extensions of the system. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate