Control system of the FOCAS instrument for the SUBARU telescope

Control software of FOCAS ( Faint Object Camera And Spectrograph) is being developed as a prototype of control software for SUBARU observing instruments. The software system consists of several processes; a network interface process, a user interface process, a central control engine process, a command dispatcher process, local control units, and a data acquisition system. Each process is communicated to other processes and controlled by passing messages of commands and its status. A control flow and generalized command messages are defined following the software guideline for the SUBARU instruments. Functionality of each process is presented. Related off-line software for making multi-slit plates and for data analysis is briefly described.