- USE ITS PLC WITH A SIMULATED PLC VERIFICATION
- USE ITS PLC WITH A SIMULATED PLC SOFTWARE
- USE ITS PLC WITH A SIMULATED PLC CODE
Recently, it is presented that O-O modeling is also appropriate for the real-time system design like an AMS as well as the business process modeling.
USE ITS PLC WITH A SIMULATED PLC SOFTWARE
O-O modeling has been mainly used as a method for the analysis and design of software system. In order to improve current PLC programming practices, significant efforts have been made in researches on object-oriented technologies in manufacturing systems. Finally, the last section summarizes results and suggests directions for future research.
USE ITS PLC WITH A SIMULATED PLC VERIFICATION
Section5 describes the automatic generation and verification method of ladder logic. Section 4 deals with O-O simulation of designed PLC-based control system for validating the correctness of control logic. Section 3 describes UML design of control logic. The rest of the chapter is organized as follows.
USE ITS PLC WITH A SIMULATED PLC CODE
Proposed framework facilitates the generation and modification of ladder code easily within a short time without considering complicated control behavior to deal with current trend of reconfigurable manufacturing systems. In order to show the applicability of proposed method, an UML-based tool for the design and generation of ladder code is also developed. Last part deals with automatic generation of ladder code from the validated design result. During the execution of simulation model, factory automation (FA) engineers can evaluate the system performance and validate the PLC control logic simultaneously. By using the results of O-O design model, an O-O simulation model is constructed and is executed. Second part is concerned with O-O simulation method for validating designed ladder control logic. O-O design model consists of three models: functional model, structure model and interaction model. Proposed framework, as depicted in Figure 1, consists of three parts: first part deals with UML design of PLC-based control system. The main objective of this chapter is to propose an object-oriented (O-O) ladder logic development framework integrating design, validation and automatic generation of ladder logic using extended UML (Unified Modeling Language). Therefore, current PLC ladder programming practices require a more integrated way to design, simulate, and generate the ladder control logic. However, since current simulation methods have mainly focused on the overall performance evaluation of manufacturing systems such as factory layouts, resource utilization, and throughput time, they have limitations with regard to the modeling capabilities of detail logic for the input/output signal-level control of AMS. Among many validation methods, computer simulation methods are widely used because mathematical formalisms have a problem of solution space explosion as the size of system increases. To generate error-free ladder code, it is also essential to validate the designed control logic of an AMS in an effective way. To deal with these frequent configuration changes of modern manufacturing systems, it is required that logic code can be generated automatically from the design results without considering complicated control behavior. Moreover, fast customer requirement changes requires flexibility of manufacturing system. So, the control logic design phase is usually omitted in current PLC programming development life cycle though it is essential to reduce logic errors in an earlier stage of automation projects before the implementation of control logic. However, currently there are no widely adopted systematic logic code development methodologies to deal with PLC based control systems in the shop floor. To cope with these challenges, a new effective and intuitive method for logic code design and generation is needed. More recently, manufacturing trends such as flexible manufacturing facilities and shorter product life cycles have led to a heightened demand for reconfigurable control systems. Currently, programmable logic controllers (PLC) are mostly adopted as controllers of automated manufacturing systems (AMSs), and the control logic of PLC is usually programmed using a ladder diagram. Among their endeavor to overcome the obstacles, one of the frequently prescribed remedies for the problem of decreased productivity and declining quality is the automation of factories ( Zhou & Venkatesh, 1999).Īs the level of automation increases, material flows and process control methods of the shop floor become more complicated. Most enterprises are struggling to change their existing business processes into agile, product- and customer-oriented structures to survive in the competitive and global business environment.
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