Hybrid Computers A hybrid computer is a combination in hardware and software of one or more analog and digital computers. It aims at providing faster, more efficient, and more economical computational power than is available with computers of either type alone. The results depend to a large extent on the exchange of information between the analog and the digital computers and on the compatibility in operations and mutual interactions between the two parts. A hybrid computer provides for the rapid exchange of information between the parallel and simultaneous computations and simulations within the analog computer and the serial and sequential operations of the digital computer. This information exchange links the two computational domains and offers the combined advantages of the fast and flexible analog computer with the precise and logic-controllable digital computer. The extent of the information exchange between the two parts and the sophistication of the control structures and in

  Analog Computer Analog computers work on continuous signals and consist of operational amplifiers, capacitors, resistors, potentiometers, diodes, switches, squarer cards, and patch cards. All the fundamental functions of computation, such as addition, subtraction, multiplication, integration, differentiation, and generation of different functions, can be carried out with an analog computer. The heart of an analog computer is the operational amplifier. The operational amplifier is a single-ended, high-gain DC coupled wide bandwidth unit, which has a very high open-loop gain, on the order of 105  to 108.  All the computer signals are referenced to a common ground. Offsets, drifts due to temperature variation, aging, and electronic noise are the main problems in the operational amplifier circuits. Hence special precautions are taken to reduce or eliminate them. Special care should be taken to minimize the electromagnetic and static coupling between different computing units and signal s

  Supervisory Control Computer   Functions Supervisory control has three fundamental functions Calculation of the present state of the process in terms of key process parameters such as yield, severity, and efficiency. Calculation of critical process constraints, such as compressor capacity, column flooding limits, explosion limits, vacuum condenser capacity, and raw material. Calculation of new process conditions, in terms of set points, which will meet the requirements of the objective function. The objective function can be one of a number of goals such as maximizing throughput, yield, and profit or minimizing deviation. Tasks The supervisory control computer requires A process model Cost functions Optimization algorithms Constraints and limits The supervisory computer typically performs the following types of tasks Determines the process operating constraints, such as a column flooding condition in distillation or a surge condition of a compressor. Basic material balance, energy ba