Software Development for a Process Control System
This resulted in rigid systems which could only be modified under considerable effort. Flexible adaption to changing conditions was only possible by the use of microprocessor technology that were configurated with assembler language functional units. A popular version is the Siemens™ SPS. With the assistance of PCs such control systems could be created even more user-friendly and more functional. Firstly the PC was intended as a pure programming tool. Later, further functions were added, such as plant configuration, recipe administration, visualization or the process leading function.
A process plant consists of many components such as valves, pumps, motors and other devices which have to be monitored and controlled. Therefore, it is necessary to conduct several measurements at different metering points and different times and to take the results into account for the subsequent adjustments. Recipes have to be managed and if required cleaning cycles have to be transmitted to the control system. Finally they have also to be protected against unauthorized access with passwords.
