ABSTRACTA versatile control system, which uses standard commercial software and hardware has been developed and applied to control oxide (and carbide) MOCVD and CVD systems. The control system is implemented within a personal computer platform. The system operates in the real time Microsoft WindowsTM environment utilizing the full advantage of the sophisticated graphical user interfaces, dynamic data exchange, networking, and multitasking capabilities. We have used two different sets of commercial software to control and monitor system hardware. The first software set is INTOUCHTM, a Man-Machine interface software from WONDERWARETM in conjunction with Microsoft ExcelTM and I/O interface software. The second software set is LABVIEWTM, which is primarily a data acquisition control system from National Instruments, combined with Visual BasicTM. Both systems include a friendly interactive real-time windows-based user interface, an advanced process entry and recording spread sheet interface, alarm and security management systems, data display and recording, maintenance routines, and complete networking and remote operation capabilities. In addition, the configurations provide a flexible hardware interface that can directly interface to I/O cards in the PC's bus, as well as to most industrial Programmable Logic Controllers, various types of process controllers, I/O devices and other forms of hardware. Most importantly, the system can interface with any in-situ process monitor or higher level intelligent process control systems in order to optimize the process. Modules may be activated or deactivated as needed (even as part of the process). These systems have been used for home-built systems, as well as to retrofit a modified Spire SPI-MOCVDTM 500XT system. General process interaction and results will be discussed.
Software requirements analysis for real-time process-control systems
