This memory requires a power supply but lends itself to modification and reprogramming. Advanced microprocessor or computer systems would normally use a combination of ROM and RAM to program control of retort functions. Algorithms are written to provide the microprocessor with a logical sequence of events for solving a problem. Control of multiple parameters such as temperature, pressure, rotation, etc may be controlled by installation of several loop controllers controlled by one PLC, microprocessor or computer. With the advancement of technology, defining the differences between microprocessors, minicomputers and mainframe computers has become more difficult.
Size is usually the distinguishing factor.
In the independent system each retort would be controlled by its own PLC or microprocessor. If one of the retort control systems failed the remainder of the systems would continue to operate. In a centralized system all data would be collected and analyzed by a central computer. This provides for quick capture of all processing information and for control from a central location. Failure of this control system would mean that all processing systems would be down.