The Knife Switch, The Relay and the IC
Remote control and data acquisition on a single or at most several wires has been under study at the AGS for some time. Recent advances in integrated circuit technology and significant reductions in the cost of Analog/Digital and Digital/Analog converters has enabled us to design a control system far cheaper (per channel) than similar automatic control schemes and which appears when all costs are included (wire, installation, etc.) to be competitive with conventional manual multiwire systems. The system is based upon the premise that the attached computer does not have to function in order for the control system to operate, but we have rejected the notion that duplicate (computer and manual) controls be developed. The new system might be likened to replacing switches with relays. The relays added additional reliability problems to the system, but their presence permitted control sequences unattainable with practical switch arrays, as well as operation with fewer personnel. The integrated circuit, serial, time multiplex system is the next evolutionary step.