مدل شبیه سازی نسل اتوماتیک بر اساس کدهای PLC و MES داده های ذخیره شده

One of the most widespread techniques to evaluate various aspects of an existing manufacturing system is discrete-event simulation (DES). However, building a simulation model of a manufacturing system needs great resource expenditures. Automated data col-lection and model buildup can drastically reduce the time of the design phase as well as support model reusability. Since most of the manufacturing systems are controlled by low level controllers they store structure and control logic of the system to be modeled by a DES system. The paper introduces an ongoing research of PLC code processing method for automatic simulation model gen-eration of a conveyor system of a leading automotive factory.

During the last few decades planning and control of production systems developed in parallel with computer sciences. As it is well known, one of the most important factors for a production firm is to secure the widest product variability and the minimum lead time. These requirements lead to complex production systems that run in a rapidly changing environment. Planning, monitoring and control of a manufacturing system can be significantly supported by creating the digital map of the real factory and processes. To make responsible production planning and control decisions of a production system based on the information of the digital factory is always a nerve-racking task because there might be differences between the digital and the real factories. So it is essential to keep digital representation valid by following the changes occurred in the real factory. The conventional way to achieve this is to refresh the digital representation manually after any (some) changes in the real factory that is a time and resource consuming task. Discrete event simulation (DES) is one of the most widely spread techniques to evaluate various aspects of a manufacturing system [2], [6] and [7]. However, on the one hand, the design phase of a simulation project needs great resource expenditures. On the other hand, simulation is usually applied to long-term planning, design and analysis of manufacturing systems. These models are termed “throw away” or “stand-alone” models because they are seldom used after the initial plans or designs have been finalized. As opposed to the “traditional” use of simulation, Son et al. proposed that once the system design has been finalized, the simulation model that was used for evaluation also could be used as the basis for system control [11]. In their concept simulation was created by using neutral system components, i.e., they made efforts to build simulation models for Shop Floor Control System (SFC), generated automatically. Data needed to build simulation models of manufacturing systems are available in production databases or

Preliminary test runs were taken on a simulation model that was built automatically based on the data on the PLC codes of a test area of the above mentioned conveyor system. The generated simulation elements were parameterized based on the historical data of this area by the suggested parameterizing method. Input data was also generated based on historical data and time dependent capacity limitations of the output of the test area were implemented in the simulation model as well.introduced. Data stored in production database were used to parameterize objects of the model and generating input for simulation experiments. ISA-95 standard was applied to define simulation object classes so as design relevant data storage of them. Preliminary test runs revealed that the behavior of the automatically generated simulation model is similar to the behavior of the real system, hence is suited to perform simulation experiments and forecasts.