PLC for Turbogas Simulator System
The system of TG simulator is incorporated by a system of signal conditioning, a supervision station, a programmable logic controller (PLC), and an operation station. The simulator includes a dynamic model of the process of turbogas. The model of mathematical is a logic group, differential equations and algebraic programmed in high level language of computation. With this model is potential to reproduce or imitate the generation unit behavior under different operation situations, for instance generation stages, startup, and synchronization. In addition, it replicates the main transitory that can happen in the unit of turbogas. The simulator was designed in “C” programming and running in a computer industry. This computer contains acquirement boards for the signals of digital, analog input and analog output.
The system of signal conditioning is a substantial interface that allocates connection and data switch over between the TG simulator and the PLC. Conditioning involves of a number of boards to sufficient the levels of electrical intensity signals and voltage transferred between the controller and the simulator. The PLC is an industrial controller of S7-400. The diagnosis and control functions, temporization, fault corrections, actualization of the system input-output signals, and communications are programmed in the PLC. The programming of control functions in the PLC was executed using structured text, ladder, and functional diagrams.
The operation place is a personal computer with the interface of graphical for the OPC client-server model and the control system operation. The interface of graphical permits the plant operator to perform sequences of supervision and operation schedules. Throughout this interface, the operator can carry out startup, stop, generation operations and synchronization. The panel of control in the operation place offers tendencies, historical records, alarm displaying, and the process variables for graphical representation. This interface of graphical was built up in InTouch, which is a stand particularly dedicated to extend human machine interfaces (HMI).
System Integration Using OPC Technology
The intelligent system modules integration and the system of turbogas simulator are depend on a client-server model. In this integration we must build up different software applications and we must use commercial software for example OPCLink and TOP Server. The aim of these applications is:
• Data exchange, access, and communication in instantaneous with the PLC
• Graphical interaction with operators and the operation of plant by the control system
• Synchronized transfer of data between applications processing in different development platforms
• The results of graphical display
• Support to the plant operator
The architecture of software is created by the intelligent system components, graphical user interfaces (GUI), and client-server applications. The interfaces of PLC were property of its producer.
The components of intelligent system generally demand control system information in synchronized, in sequence to present this requirement, an open communication that permits interoperability with the part control is necessary to use. OPC is a general industrial standard for distribution data between software applications and industrial controller build up in different programming languages. The client set up a connection with the server via COM Microsoft technology in architecture of OPC client-server. Multiple clients should correspond concurrently by only one server. The server of OPC is a vital component in the system because it allows operations of read/write from the process variables, the server of OPC used in the system is a TOP Server S7-MPI. The two OPC server has important functions are:
1) Process controller data access and connection,
2) The system data provider to the client applications.
This driver is set up in the operation place and it was constructed for accessing the control database of PLC process.
The software architecture has two clients: LV Client and OPCLink. LV Client is a client remote that assembled in the supervision place and it is an application built up in graphical programming. OPCLink is a commercial client set up in the operation place with the TOP Server.