Digital microprocessor

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 ... 

They modified an existing autoclave and a real-time digital microprocessor control system so that It could be operated In a semi-continuous mode. Various components of MSW were studied In order to obtain meaningful data, not confused by the different thermokinetics of different MSW components. Feedstocks Included wood flour, cardboard, newsprint and rice (starch), as well as the Important model compounds alpha cellulose and lignin. It was found that these MSW components could be converted to liquid oils and a high-heating value residual solid at temperatures of 325 0 to 400 0 and pressures of 1000 psl to 3000 psl. 

So, what do these numbers actually mean This simple question actually gets to the core issue. In older, analog systems with discrete components it was possible, in principle, to take failure rate data for each component and thereby determine an overall system reliability, using basic arithmetic. Now that most new systems are digital (microprocessor-based), although it is stiU possible to do a failure rate calculation for the hardware parts of the system, the reliability of the software cannot be determined by numerical means. And, furthermore, the reliability of the software is likely to dominate the overall system reliability. 

With the advent of the microprocessor, digital technology began to be used for data collection, feedback control, and aU other information processing requirements in production facUities. Such systems must acquire data from a variety of measurement devices, and control systems must drive final actuators. 

Microprocessor technology permitted these technical issues to be addressed in a cost-effec tive manner. In the mid-1970s, a process control architecture referred to as a distributed control system (DCS) was introduced and almost instantly became a commercial success. A DCS consists of some number of microprocessor-based nodes that are interconnec ted by a digital communications network, often called a data highway. The key features of this architecture are as follows ... 

Initially, the microprocessor-based single-loop controllers made the power of digital control affordable to those with small processes. To compete with these products in small applications, the DCS suppliers have introduced micro-DCS versions of their products. As a PC-based operator interface is usually a component of the micro-DCS, there is sometimes little distinction between a micro-DCS and a system consisting of single-loop controllers coupled to a PC-based operator interface. 

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... 

Presently, fieldbus controllers are single-loop controllers with 8- and 16-bit microprocessors and are options to digital field-control devices. These controllers support the basic PID control algorithm... 

The control logistics such as PWM or frequency controls tire digital circuits and are microprocessor based. They can comptire the actual inverter output parameters with... 

Solid-state microprocessor based these are more sensitive and accurate. They can be made digital to be connected to a computer for remote monitoring and control of the process that the motor is driving. 

The foregoing demonstrates that modern digital devices offer highly reliable, state-of-die-art microprocessor technology that controls turbomachinery strings, monitors operating data, stores data for subsequent evaluation, communicates to odier systems, and can expand with future technologies. 

The advanced control room uses fiber optics, microprocessors, and digital monitoring and control. This includes self-testing, automatic calibration, user interactive from panels, full multiplex, standardization of the man-machine interface, common circuit cards, and wide-range flux monitors to eliminate range switching on startup. 

Digital control A control loop in which a microprocessor-based controller directly controls equipment by means of sensors. Its operation depends on a series of on-off pulses arranged to convey information. 

The battery-powered electronics acquire and store sonic waveforms. Under the control of a downhole microprocessor, the transmitter is fired, and four receiver waveforms are simultaneously digitized at 12 bits and added to a signal stack. The transmitter firing is done in bursts at the rate of 10 Hz, which allows minimum movement while stacking. 

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