The PLC: still useful after all these years

Programmable logic controllers (PLC) have gone beyond their original function as relay replacements in factory floor control systems to encompass diagnostics, information gathering and analysis. Several trends are emerging that increase PLC functionality while further blurring the line between PLCs and computer. Long-term-memory devices such as hard disk drives are being installed in some prototype PLCs to allow on-site storage of data previously stored elsewhere. Connecting PLCs to minicomputers allows businesses to make full use of the real-time data collected on the factory floor. Future developments in PLC use include linking PLCs into more powerful networks and the use of structured programming to create reusable PLC software.
PRODUCTION State-of-the-Technology Report: Unless you're intimately involved with them, you may be wondering about programmable controllers, about the viability of those electronic boxes that have been around since 1969. After [...]