Control electronic logic

The purpose of the various electromechanical elements of a circuit is to effect monitoring, safety and automatic control, and these may he connected separately into a custom-huilt system. The availahility of electronic logic circuits gives the possibility of integrated systems and superior control, using a large number of input signals. Observed parameters are ... 

Most processes operate more efficiently when functions must occur in a desired time sequence or at prescribed intervals of time. In the past, mechanical timers and logic relays were used. Now electronic logic and timing devices are used based on computer software programmable logic controllers. They lend themselves to easy set-up, reprogramming, and provide more accurate control. 

The component controllers used in the controller subsystem portion of the DCS can be of various types and include multiloop controllers, programmable logic controllers, personal computer controllers, singleloop controllers, and fieldbus controllers. The type of electronic controller utilized depends on the size and functional characteristic of the process application being controlled. See the earlier section on distributed control systems. 

Double-entry of the data should be performed. Data validation methodology (proofreading, double-data entry, electronic logical control) should be specified in writing. 

ACC differs from other vehicle control functions, especially in that the function is performed by several electronic control units (ECUs). While conventional control systems consist of a sensor and actuator environment around a central ECU, ACC adds functions to existing systems. A truly new component is the sensor for measuring the distance, relative speed, and lateral position of potential target vehicles, using laser optics or millimeter waves. This component often contains the logic for controlling vehicle movement. The latter is affected by commands of ECUs for engine and brake control electronics. 

Controls (1) provide closed-loop control of temperature, pressure, and thickness (2) maintain preset parameters (3) monitor or correct equipment operations (4) con-standy fine tune equipment (5) provide consistency and repeatability in the operations and (6) provide self-optimization of the process. Most processes operate more effi-ciendy when functions must occur in a desired time sequence or at prescribed intervals of time. In the past, mechanical timers and logic relays were used. Now electronic logic and timing devices are used based on computer software programmable logic controllers. They lend themselves to easy set-up and reprogramming. See computer batch processing computer continuous pro-... 

Failsafe Operation—Utilize sensors, controls and logic in such a manner that their failure or loss of power would produce the least undesirable consequences. In case of power failure, circuits must be manually re-energized to restart. The overall start and stop function must be hardwired, which eliminates the dependence on an electronic device or controller. 

Electronic and programmable electronic logic solvers use internal low-level logic signals. Use of low-level logic outside the shielded controller cabinet may be inappropriate. 

Electrical and electronic logic to use only logic controlled by the user under a formal revision and release control program. 

The invention of the germanium transistor in 1947 [I, 2] marked the birth of modem microelectronics, a revolution that has profoundly influenced our current way of life. This early device was actually a bipolar transistor, a structure that is mainly used nowadays in amplifiers. However, logical circuits, and particularly microprocessors, preferentially use field-effect transistors (FETs), the concept of which was first proposed by Lilicnficld in 1930 [3], but was not used as a practical application until 1960 [4]. In a FET, the current flowing between two electrodes is controlled by the voltage applied to a third electrode. This operating mode recalls that of the vacuum triode, which was the building block of earlier radio and TV sets, and of the first electronic computers. 

Nevertheless, SET devices, as they can build up with chemically tailored building blocks, control the motion of just a few electrons instead of several hundred or thousand ones. Since power consumption is roughly proportional to the number of electrons transferred from a voltage source to the ground in logic operations, SET devices may reduce the power consumption drastically [85]. 

Research on multi-qubit molecules starts with the synthesis and characterization of systems that seem to embody more than one qubit, for example, systems with weakly coupled electron spins. Indeed, many molecular structures include several weakly coupled magnetic ions [76-78]. On a smaller scale, the capability of implementing a Controlled-NOT quantum logic gate using molecular clusters... 

---