Microprocessors, in process

A detailed discussion of the application of digital computers and microprocessors in process control is beyond the scope of this volume. The use of computers and microprocessor based distributed control systems for the control of chemical process is covered by Kalani (1988). 

The use of microprocessors in process GCs allows the GCs to become an integral part of a gas company s data acquisition system. 

In spite of the problems, one confident prediction that can be made for the rubber industry is that the use of microprocessors in process control will grow significantly in the next few years, though its growth may be slower in the mixing area than in other processes. 

More microprocessor-based process equipment, such as smart instruments and single-loop controllers, with digital communications capability are now becoming available and are used extensively in process plants. A fieldbus, which is a low-cost protocol, is necessary to perform efficient communication between the DCS and these devices. So-called mini-MAP architec ture was developed to satisfy process control and instrumentation requirements while incorporating existing ISA standards. It is intended to improve access time while... 

The use of computers and microprocessors (also known as programmable electronic systems [PES]) in process control continues to grow. They have brought about many improvements but have also been responsible for some failures. If we can learn from these failures, we may be able to prevent them from happening again. A number of them are therefore described below. Although PES is the most precise descnption of the equipment used, I refer to it as a computer, as this is the term usually used by the nonexpert. 

The character and the degree of automation in chemical control may have been covered in the above treatment of semi-automatic or completely automatic, and of discontinuous or continuous analysis, but something more should be said about the means by which automation proper has been performed in recent times. Whereas in the past automated analysis involved the use of merely, mechanical robots, to-day s automation is preferably based on computerization in a way which can best be explained with a few specific examples. Adjustment knobs have been increasingly replaced with push-buttons that activate an enclosed fully dedicated microcomputer or microprocessor in line with the measuring instrument the term microcomputer is applicable if, apart from the microprocessor as the central processing unit (CPU), it contains additional, albeit limited, memory (e.g., 4K), control logics and input and output lines, by means of which it can act as satellite of a larger computer system (e.g., in laboratory computerization) if not enclosed, the microcomputer is called on-line. 

Digital computers are used in process control systems on a time-shared basis. A single digital computer (or microprocessor) services a number of control... 

Civera, P., DEL CORSO, D. and Greooretti, F. In Microprocessors in Signal Processing, Measurement and Control, Tzafestas, S. G. ed. (Reidel, London, 1983). Microcomputer systems in real-time applications. 

In the 1980s microprocessor driven applications and sensor interfaces entered the market, and also a variety of conventional sensors were used to create sensor systems by simply adding different sensors and using sensor bus systems or smart distributed systems [2]. In process technology, aircraft and automotive applications distributed conventional sensor systems are now state-of-the-art. 

Many laboratory instruments available on the market today contain built-in microprocessors that process data collected on samples and display or send the answer to a computer. In addition, they may have an interface that attaches to an external computer for processing the data generated by the instrument. With regard to experiments or analyses performed frequently, it is often desirable to interface the instrument to a computer to aid in the subsequent analysis of data. Some of the commonly encountered systems following. 

Lead-tin alloys are the most commonly used solder materials for microelectronic packaging. Pb and Pb-rich alloys have one of the most desirable characteristics of C4 solders in that they are soft and compliant. The compliant nature of these alloys act a cushion for absorbing thermal and mechanical stresses and transfer minimum stresses to the die during microprocessor assembly processes. On the other hand, the melting... 

The DRAM is also assumed to be built in a 0.13 pm process. The memory bus between L2 cache and DRAM is placed in the middle of the L2 cache, which is marked as red rectangles in Fig. 3.10. The DRAM will be placed on the top of the microprocessor in a way illustrated by Fig. 3.11. As for the main memory, we selected a high-end, Rambus DRAM with a clock of 1 GHz. Since the CPU clock has a frequency of 4 GHz, the access cycle time of the main memory is 4 CPU cycles. In the remaining part of this section, the word cycle always refers to a CPU cycle. On the other hand, the memory latency value is usually determined by the specific machine configuration and typically values are in the range of 100 cycles to 500 cycles (e.g., [20]). Because our target microprocessor is very aggressively clocked, we assume a memory latency of 400 cycles. 

What are the basic and most important advantages offered by digital computers in process control Discuss the size, capabilities, and prices of the most recent digital microprocessors available in the market. Do you realize the inexpensive potential that they offer for process control ... 

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