EXPERIENCE WITH THE STATE NOTATION LANGUAGE AND RUN-TIME SEQUENCER

The State Notation Language (SNL) has gained wide acceptance as a control system development tool. The SNL uses a subset of C with additional control statements that are based on the state transition diagram paradigm. In conjunction with a run-time sequencer, the SNL offers programming simplicity without significant performance penalty. As one of the major tools in the Experimental Physics and Industrial Control System (EPICS), the SNL has been successfully used on several control systems in a wide variety of applications, such as machine sequencing operation of beam diagnostics and facilitating complex operator interface functions. This paper presents the results of a survey of the various users of the SNL. The intent is to judge how well the SNL has met its original objectives and to determine future improvements. Such improvements will include implementing a graphical sequencer builder and providing a comprehensive graphical debugging tool.