Both MATLAB 5.0 and SIMULINK 2.0, its dynamic system simulator, are marked
as major upgrades with new "look and feel" interfaces. It is expected that you
are familiar with MATLAB's syntax structure and environment before you use
SIMULINK appears as an icon on MATLAB's menu system, with the Workspace Browser. The Browser is a static display of all variables and arrays in MATLAB's workspace. Unlike in the Mac version, you can't do much with the Browser other than view and clean the workspace.
Once SIMULINK is loaded, a new window with the block diagram libraries appears. To start building your model, drag the diagrams into the workspace. The block building process is very simple and intuitive. You can cut, paste, copy sections of the model, create groups of blocks to perform a certain task, or change the screen attributes of any entity of the model. But although the block connections are easy to construct and modify, SIMULINK lacks a tool that can detect intersecting lines with different origins and destinations and either reroute them or make them distinguishable.
You can control the complexity of your model by creating submodels for parts of the system that perform a certain task. Two new powerful functions of subsystems are introduced in SIMULINK 2. A Conditionally Executable Subsystem lets you control the execution of an event while certain conditions are met. You can also have a trigger event controlling the execution of a specific subsystem.
You can start a simulation from within SIMULINK or from MATLAB's Command line. Monitors can send information to a file or display it on-the-fly. The graphical part of these monitors, called Scope, addresses the basic graphical output during the simulation, leaving the more complex plotting to MATLAB's graphics routines. Although Scope has many enhancements for setting controls, it still needs a built-in printer option. Currently you must use MATLAB's graphics commands to capture the Scope data for plotting and printing.
You can attach monitors anywhere to watch the simulation's progress. Monitors can plot single variables or, after multiplexing the blocks, you can show in a single plot the variation of several locations in the model. The Scope can float on screen, acting as a monitor of any point in the model.
You start a simulation by specifying the simulation parameters. While the simulation is running, you can open the blocks of your model, change the variables or integration algorithm, and view the results on the model's monitors.
The interface functionality of your models can increase with MATLAB's graphical user interface (GUI) capabilities. The GUI lets you add special effects such as pop-up menus. You can also animate simple physical systems with building blocks. The GUI, animation tools, or other MATLAB commands can be automatically executed in a transparent interface.
The simulations are normally running in the "interpreted mode," which implies relatively slow response and execution. SIMULINK's Accelerator option allows you to create and compile C code for your models, which will drastically increase the speed of the simulation process. The Accelerator functions in a transparent mode and, once invoked, will recompile and link the modified model. A glitch in printing prevents SIMULINK models from printing when the model extents exceed the paper size. The alternative is to use the clipboard to copy in Metafile or Bitmap format for use with other Windows applications.
Mathworks tried to integrate the two packages and eliminate redundancies in tasks and functionality. SIMULINK represents a value on its own as a system builder, complete with a GUI and enhanced tools for any level of complexity. The graphical output capabilities are not fully integrated without some customization by the user. The GUI builder and its nice tools could help in this situation with some ready-to-use templates.
Spec Box: SIMULINK 2.0 with MATLAB 5.0
SIMULINK provides the tools for modeling and analysis of any dynamic system represented as a block diagram. The Windows 95 or NT version requires an 80486 or Pentium with at least 8 to 12M bytes of RAM, 50M bytes of free disk space.
List Price: $3,700
The MathWorks, Inc.,
24 Prime Park Way,
Natick, MA 01760
ph: (508) 647-7000
A similar product: VisSim
487 Groton Rd.,
Westford, MA 01886
ph: (508) 392-0100