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Control of a flexible manufacturing cell by Petri nets

in Java language.

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ObjetivObjetiveess

Configurating the PCI SC/I-T controller board via CMD’s HLI.

Create a set of Java classes that can access to the bus.

Create a Java implementation of Petri nets to control the manufacturing cell via Interbus.

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The The PCI SC/I-TPCI SC/I-T controller board controller board

4th. Generation Interbus controller board.

Remote interface for PCI bus.

Total configuration of the controlled system process data by CMD software.

Permits permanent storage of process data in its EEPROM memory.

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InterbusInterbus

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CMDCMD

Phoenix-Contact bus configuration software Can export bus configuration to a high-level

languaje. Auto-configuration.

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JNIJNI

Interconnect Java with C libraries. Solution: changing the C functions

created by HLI for being used from a Java application.

Java provides this funcionality: JNI (Java Native Interface).

Now we only have to find a method for representing the system to control: Petri nets.

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Java programmingJava programming

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Petri netsPetri nets Petri nets (PN) are a modelling and analysis tool

especifically adapted to the study of discrete events systems.

A set of classes have been implemented for representing a PN: Place, Transition, Net.

Two ways for creating a PN: direct code writing or importing a PN from an external editor.

We have used HPSim, a free PN editor that exports a PN into a .txt file; the class TextToNet translates the created PN into a Net object inside our project.

99Petri netsPetri nets

Station automaticStation automatic

production production

independent netsindependent nets

InicializatiInicializationon

netnet

Global control net

1010

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ControlControl

Class Coordinator implements the evolution of the PN: habilited transitions, fires and marking. Actualizates the monitor/s values.

Monitors hold the variables: station inputs and outputs, array of orders, etc.

After a fixed delay the class BusManager actualizates the station output variables from the monitor objects values and actualizates from the bus the input values.

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Xplore project MembersXplore project Members

Ramón Piedrafita MorenoAlberto Gran TejeroOscar García Flores

Universidad de ZaragozaUniversidad de Zaragoza

Video (Media Player) Video (Quicktime)