Library simulation components

The main distinguishing feature of semicustom ASICs, compared to full custom ones, is that the basic circuit building blocks, whether analog or digital, are already designed and proven to work. These basic circuits typically reside in libraries within a CAD system. The users simply select from the library the components needed, place them on their circuits, and interconnect them. Circuit simulation is also done at a much higher level than SPICE, and the designer is, therefore, not required to be familiar with either semiconductor or device physics. 

In this library, each component design is based on a simulated model developed using commercially available electromagnetic simulation tools. Mechanical layouts were generated based on these models, and parts were manufactured. S-parameter files included in the design kit reflect verified... 

In the area of the simulation design, we have compared two scenarios for developing simulation models. If the simulation library with simulation components is available, the simulation model can be semiautomatically assembled from these components. As future work in the simulation model design area, we will tackle the transformation of energy between various physical disciplines, such as between electrical and mechanical systems. The common problem of simulation design and integration that we will address in the future work is the validation of designed simulation models, especially in the relationship to the used components, from which the simulation is assembled. 

Each vendor of SPICE simulation software has added features such as Monte Carlo analysis, schematic entry, and post simulation waveform processing, as well as extensive model libraries. In most cases, the manufacturers have modified the algorithms for controlling convergence and have added new parameters or syntax for component models. As a result, each electronic design automaton (EDA) tool vendor has the basic Berkeley SPICE 2 features and a unique set of capabilities and performance enhancements. 

Users can create their own models, but most of the time they will depend on the model libraries provided by a vendor. The library models that do not use pure Berkeley SPICE 2G.6 syntax are unique to that particular simulator. While the SPICE syntaxes of each product are similar, they are not exactly compatible both distinct and subtle differences exist. However, in many cases, most models in vendors libraries have been provided by the component manufacturers. These models are available for free on the Internet. 

Based on a project (or logistics) class description of the electronic data management system, and the library of technical components it is possible to simulate any system in connection with the planning tasks. Figure 5 shows the integration scheme of different simulation systems for the planning aspects. 

None of the commercial process simulators contains a good library model for adsorptive separations or membrane separations at the time of writing. These separation methods are important for gas-gas separations, chromatographic separations, and size-exclusion or permeation-based separations. All of these processes must be modeled using component splitters, as described next. 

A component splitter is a subroutine in the simulation that allows a set of components from a stream to be transferred into another stream with a specified recovery. Component splitters are convenient for modeling any separation process that cannot be described using one of the library models. Examples of real operations that are usually modeled as component splitters include... 

When the design engineer needs to specify a unit operation that is not represented by a library model and cannot be approximated by a simple model such as a component splitter or a combination of library models, then it is necessary to construct a user model. All of the commercial simulators allow the user to build add-in models of varying sophistication. 

The research works performed for several years within the PSE research department (LGC) on process modelling and simulation have led to the development of PrODHyS. This environment provides a library of classes dedicated to the dynamic hybrid simulation of processes. Based on object concepts, PrODHyS offers extensible and reusable software components allowing a rigorous and systematic modelling of processes. The primal contribution of these works consisted in determining and designing the foundation buildings classes. 

The appropriate selection of thermodynamic models is probably the most important aspect of a simulation work. Sometimes preliminary work is necessary to estimate physical properties for non-library components, or to identify the parameters of thermodynamic models from experimental data. A thermodynamic model may be valid for the whole flowsheet, or only for some units. Specific thermodynamic options at unit level will increase the reliability of the results. For the HDA process we have the following possibilities ... 

Crew Station/equipment characteristics The crew station design module and library is a critical component in the MIDAS operation. Descriptions of discrete and continuous control operation of the equipment simulations are provided at several levels of functiontil deteiil. The system can provide discrete equipment operation in a stimulus-response (blackbox) format, a time-scripted/ event driven format, or a full discrete-space model of the transition among equipment states. Similarly, the simulated operator s knowledge of the system can be at the same varied levels of representation or can be systematically modified to simulate various states of misunderstanding the equipment function. 

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