This paper presents the concepts developed to create a program, SIMORD, used to simulate hierarchical configurations of distributed process control computers. To achieve adequate response times under all critical conditions, the distributed process control computer systems should be designed from two points of view: functions distributions and performance planning. Performance criteria can be specified both in terms of system response time to alarm conditions and the maximum activity rate for each processor during steady-state service. Based on these characteristics, different computer configurations can be evaluated and compared through simulation in order to select the best control system for a particular physical-chemical process. The results, in abbreviated form, of the simulation of a hierarchical configuration of computers controlling a wastewater treatment plant are presented. © 1988.