![]() Two basic sub-classes are PTPetriNet, which implements Place/Transition Petri net class and CPetriNet, which implements simple coloured Petri net class. All classes are based on an abstract APetriNet object class in order to standardize basic Petri net properties and methods. Different Petri net classes naturally map to object classes in the software implementation of the developed toolset. The specifics of MMT server environment as well as improved object oriented programming support in recent versions of Matlab motivated the development of a new object oriented toolset, which can be used to build, analyze and simulate Petri net models in a script based manner without a dedicated user interface. Matlab implementation The previously developed PetriSimM Petri net toolbox is based on Matlab graphical user interface with callbacks to a number of m-script functions. Much of the research deals with basic timed continuous Petri nets (CCPN) where maximal firing speeds are constant. ![]() The token flow through firing transitions becomes continuous. If a token count of a place is replaced by a token quantity, firing of a transition only removes a fraction of the token quantity from its input places. A definition of simple Coloured Petri nets (CPN) without transition guards can be derived by folding places and transitions of the P/T Petri net. This way the structurally complex P/T Petri net models can be represented in a compact form, while preserving the model behaviour. Coloured Petri nets enable to distinguish among tokens based on an assigned attribute, which is called colour. firing durations, holding durations and enabling durations. Therefore various authors extended Petri nets with time representation, e.g. For many practical applications, execution times have to be considered. The concept of time is not explicitly given in the original definition of Petri nets. ![]() The basic Place/Transition Petri net model can be extended in different ways, leading to other Petri net classes. The resulting Place/Transition Petri nets became a central model, which is well explored in terms of analysis and synthesis techniques. Later a number of modifications of the basic system model was introduced, including integer markings and weighted arcs. Petri nets and Petri net classes Petri nets were initially introduced in the form of Condition/Event Systems with only binary markings and simple arcs. Therefore an object oriented Matlab based Petri net kernel was implemented that can be used to implement simple examples within MMT server environment. Petri nets are widely used modelling formalism for description of discrete-event systems with highly parallel and cooperating activities. An increased interest in discrete-event and hybrid systems motivated the investigation of possible implementation of Petri net based examples on the MMT server. Most examples on the MMT server are implemented in Matlab and recent developments include the ability to implement complex examples by various Matlab modelling and simulation toolboxes, including Simulink and Simscape. Main model parameters of examples can be adjusted and the parameter effects can be observed. TheMMT-web server is a part of the E-learning infrastructure at Vienna University of Technology, which enables students to get basic insight into the field of simulation and modelling in a user-friendly way.
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