Proceedings of the 1988 Winter Simulation Conference M. Abrams, P. Haigh, and J. Comfort (eds.) Introduction to SIMAN Deborah A. Davis C. Dennis Pegden Systems Modeling Corporation The Park Building 504 Beaver Street Sewickley, PA 15143 ABSTRACT This paper discusses the concepts and methods for simulating manufacturing systems using the SIMAN simulation language. SIMAN is a general purpose simulation language which incorporates special purpose features greatly simplify and enhance the modeling of the material handling component of a manufacturing system. 1. INTRODUCTION This paper discusses the use of SIMAN simulation language for modeling manufacturing systems (Pegden 1982). SIMAN is a general-purpose SIMulation ANalysis program for modeling combined discrete-continuous systems. The modeling framework of SIMAN allows component models based on three distinct modeling orientations to be combined in a single system model. For discrete change systems either a process or event orientation can be used to describe the model. Continuous change systems are modeled with algebraic, difference, or differential equations. A combination of these orientations can be used to model combined discrete-continuous models. SIMAN incorporates a number of important features which have contributed to its rapid growth in popularity. Some of the significant features include the following: 1. SIMAN is designed around a logical modeling framework in which the simulation program is decomposed into a model frame and an experiment frame. 2. SIh4AN incorporates a number of unique and powerful general-purpose modeling constructs which represent a natural evolution and refinement of existing language designs. 3. SIMAN imbeds within this general-purpose framework a set of special-purpose constructs which are specificahy designed to simplify and enhance the modeling of manufacturing systems. Many general-purpose languages lack the special-purpose manufacturing features provided by SIMAN. On the other hand, existing special-purpose manufacturing languages such as SPEED (Gross and Ippolito 1982), XCELL+ (Conway et al. 1987), and SIMFACTORY (CACI Products Company, 1986) are intended for a restricted class of manufacturing systems and are not applicable to systems in general. 4. SIMAN runs on mainframe, mini, and microcomputers. All versions, including the microcomputer versions, are completely compatible. Models can be moved between computer systems without modification. 5. SIMAN includes an interactive graphics capability for both building models and experiments, and displaying the outputs from the model. 6. SIMAN incorporates an interactive debugger which allows you to interactively monitor and control the execution of the simulation. Errors can be isolated and corrected during the execution of the simulation without the need to recompile, relink, and rerun the simulation. 7. SIMAN models can be used within the CINEMA system (Systems Modeling 1985) to generate real-time, high-resolution color graphics animation of the system dynamics. This provides an extremely powerful new tool for both understanding and explaining the dynamics of a system. 8. SIMAN’s modular structure and powerful modeling capabilities encourage integration with other analysis technologies and interfaces such as SimStarter (Suri and Tomsicek 1988) providing sets of compatible tools for rapid modeling and analysis. SimStarter provides the user with the ability to easily convert a Manuplan II analytical model to a SIh4AN simulation model. Thus, a user may use Manuplan II to quickly create an analytical model of a system, then use the SIMAN model created by SimStarter to perform detailed simulation analysis, evaluating the effects of such system characteristics as buffer size limits and specific scheduling policies which cannot be analyzed using analytical tools. This seamless integration of tools allows the use of the “right tool at the right time” without duplication of effort as the modeling process proceeds from analytical model to detailed simulation. 61