A new method for solving a class of nonlinear equations

On preferring iteration in a transformed variable to the method of successive substitution

The use of control systems reduces the need for human involvement in food processing plants, reduces stress in the production process, and makes production more efficient and cleaner A control system was designed for a poundo yam processing plant using the estimated time required by each machine in the plant and the sequence of operation A flow chart was developed to analyse and study the timing and motion of individual machines and to control the operation of the machines The C++ programming language was used to programme the programmable logic controller A circuit was developed to control the electric motors, electric heaters and fans in the processing plant Evaluation of the developed control system shows that it reduces the time spent per batch production from 7 hours to 5 hours 19 minutes (2405% time reduction) and increases the efficiency of the plant from 734% to 8490% Human involvement was reduced by 75% (from 8 steps to just 2)

A control system for a poundo yam flour processing plant

Distributed control in the textile industry

Recent developments in microprocessor technology have made it possible to design control schemes far different from the traditional ones. Instead of large control rooms whose walls are lined with instruments, displays, annunciators, and so on, major plants can now be run by a few operators seated at video display terminals. Instead of trying to keep track of hundreds of instruments, these operators are concerned mainly with process parameters that are out of limits, or are trending in that direction. The control system selects these items and calls the operators' attention to them, using color, flashing displays, etc. This article explains what the chemical plant design engineers must provide to the control-system supplier, so that it can put together a complete control system, and provide the plant designers with a proposal and bid. The article then goes into the procedures by which plant designers can evaluate the proposals from various control-system suppliers and choose the one best suited for them.

G.T. Doyle

Papers

Microprocessor-based distributed control systems