GE-PAC 4020/EAI 580 Hybrid Computing System

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Virginia Polytechnic Institute and State University


Hybrid computation is a discipline designed to reap benefits from the strengths of both digital and analog computation. This system welds the capabilities of a GE/PAC®M/sup> 4020 Process Computer and an EAI® 580 Analog/Hybrid Computing System by means of a special Hybrid Interface.

The Hybrid Interface consists of five modules. First, there is the hybrid control module which mediates status and control information between the two computers, and the D to A converter module which provides analog voltages from digital information. Then, there is the analog scanner/controller. which switches voltages from the analog computer to the A to D converter, and the A to D converter itself. Finally, there is a logic interface which exchanges digital signals between the analog computer's logic module and the digital computer.

The interface scheme allows either computer to act as the master control, and it provides for full interchange of a problem's parameters between the digital and analog regimes as a problem solution unfolds. The system is fast enough to study many large problems in real-time with good accuracy.