Programmable Controller Power in a Bulk Material Handling System

Traditionally, the primary use of the programmable controller in a bulk material handling system has been the sequential interlocking and control of conveyor systems. In addition, today's modern programmable controller has the power to accomplish data processing tasks as well. It is the intent of this paper to describe a project, an iron ore pellet transshipment terminal, utilizing the full power of the programmable controller. The project will use two (2) programmable controllers. One 16K (16,384) word PC and one 32K (32,768) word PC. A word being 16 bits in size. The completed project will have 1,487 I/O points, 1,000 of these I/O will be at remote locations at distances of up to 2,500 ft. To enhance the I/O capacity of the programmable controller, the project will use a multiplexing device. The multiplexer extends the physical distance between the programmable controller's own I/O racks and additional remote locations. The programmable controller will have two operating systems (OS). The OS for the sequential control of the project will be ladder line programming with diagnostics. The OS for the data processing will be called D-Log. Both OS's run simultaneously and interact with each other. The link between the two OS's is called a math logic unit. The programmable controllers will have to be interfaced with various peripheral devices to complete the project. Sequential control peripherals include three general purpose ASCII CRT terminals, BCD thumbwheel switches, LED displays, pushbuttons, limit switches, and indicating lights. Data processing peripherals include one general purpose ASCII CRT terminal, three high speed serial printers, and one remote card reader. Interfacing of all the devices described thus far will comprise the main body of the paper, while electrical quantities and units will only be stated.