In a programmable controller system, the central processing unit (CPU) provides both the heart and the brain required for successful and timely control execution. It rapidly and efficiently scans all of the system inputs, examines and solves the application logic, and updates all of the system outputs. In addition ,it also gives itself a checkup each scan to ensure that its structure is still intact. Included will be the various functional blocks in the CPU, typical scan techniques, I/O interface and memory uses, power supplies, and system diagnostics.
It is this attribute that makes programmable controllers the powerhouses that they are today in solving tough factory automation problems. The factory of tomorrow will run efficiently only if quality information about process needs and status of the process equipment are known on a realtimes basis. This can and will come about only if the unit level controllers, including programmable controllers, are empowered with the ability to collect, analyze, concentrate, and deliver data about the process. As the market continues to exhibit this demand, manufactures are likely to continue to outfit their controllers with more and more variable memory, and enhanced instruction sets to perform these tasks.
