Centralized control instrumentation

The term control panel refers to the instrumentation console in a central control room through which process information is communicated to the process worker and via which the worker changes the state of the process. This category includes display elements such as chart recorders, bar indicators, dials, and modem VDU-based systems together with control elements such as buttons, switches, track balls and mice. The control panel is the human-machine interface (see Chapter 2) that has traditionally received the most attention from human factors specialists. 

Stop, start, emergency stop and speed controls are grouped adjacent to the engine, and the machine is usually equipped with instrumentation for monitoring its safe operation. Very often, a centralized control room is provided, particularly when there are a number of units in operation. Typical signals monitored and recorded remotely are ... 

Inhibitor control can be effected by conventional methods of chemical analysis, inspection of test specimens or by instrumentation. The application of instrumental methods is becoming of increasing importance particularly for large systems. The techniques are based on the linear (resistance) polarisation method and the use of electrical resistance probes. They have the advantage that readings from widely separated areas of the plant can be brought together at a central control point. (See Section 18.1.)... 

Substential instrumentation, central control panels, petrochemicals MISCELLANEOUS CHEMICAL PLANTS Little instrumentation, solids... 

In order for the data generated by the analyzer to be useful, it must be transferred to the operation s centralized control or host computer and made available to process control algorithms. Vendor packages manage instrument control and can do spectral interpretation and prediction or pass the data to another software package that will make predictions. Most vendors support a variety of the most common communications... 

The instrumentation developed employs units for (1) automation of the basic operations (2) sample transport (3) central control (4) the entry and weighing station and (5) the output for results and logistics. 

A central location where instrument leads are short is preferred. In modem facilities with distributed control systems, all units are controlled from a central control room with few operators. Only a few roving operators are available to spot trouble. It is desirable to deep process equipment a minimum of 8 m away from the control room. Any equipment and hydrocarbon-containing equipment should be separated by at least 15 m if possible. Most control rooms are designed with blastproof construction and have emeigency backup power and air conditioning. The room is pressurized to prevent infusion of outside air that may have hydrocarbon content in the explosive range. 

Figure 11 -7 Workstations with clusters of tike Instruments (e.g., chemistry analyzers, Chem I through Chem 4, or hematology analyzers, Heme 1 through Heme 4) enable one technologist to operate and monitor the functions of several analyzers simultaneously. The central control module is usually provided by the manufacturer of the analyzers in each duster. (From Boyd JC, Felder RA, Savory j. Robotics and the changing face of the clinical laboratory. Clin Chem 1996 42 1901-10.)...

Automated Computer controlled usually through a personal computer or programmable logic controller. Less frequently by a central control computer or as part of a distributed control system Better repeatability Better process control Lower operating labor costs Data gathering automatic although some analytical instrumentation may remain off line Some to all routine operations may be automated... 

The central control room provides surveillance and direction for all phases of TOCDF activities. It is kept at a higher positive pressure to prevent the possibility of any agent entering it, and the air intake is doubly filtered. Several consoles Une the room, each with two advisor screen monitors, two closed-circuit TV monitors, and a keyboard through which commands are entered to control plant operations. Redundant computers, software, and plant instrumentation ensure that continuous realtime control is maintained. 

Following development of pneumatic field control systems came the idea that a control house was needed to incorporate all controls for a process into a central room. Pneumatic transmitters, including the development of dP cells for flow measurements, provided the next step in instrumentation and moved the local process control room into a central control house for the entire plant. 

This continuous process is operated from a centralized control panel which contains more than one hundred recorders and controllers. In addition, a data-reduction system continuously scans 70 key temper ures and at intervals types them out on the plant log. If, in the scanning process, a deviation from control is noted, the operator is notified by an alarm and the deviating data are recorded automatically. The control panel also contains start-stop switches for all motors. Included in the instrumentations are an infrared analyzer on the nitric oxide stream, a hydrogen analyzer on the derivative autoclaves, and a mass spectrometer for nitroparaffin analysis. 

The equipment is of such a nature that it can be protected more economically without a building and can be operated via automatic control instrumentation from a small central control building. 

Vitrification Cells. Liquor is fed from the HAL cell to one of the two duplicate vitrification cells in the WVP. These house the main chemical process equipment, namely the calciner, melter, and primary off-gas vessels. The Vitrification Cell equipment evaporates the HAL liquor to dryness, mixes it with pre-formed glass (inactive) and other additives, and melts the mixture to form the glass product at a temperature of around 1100 C. The primary off-gas system removes dust, water vapor, and a proportion of the radioactive species that are entrained in the off-gas stream. HAL liquor is fed continuously into the Vitrification Cell and the glass product is poured in batches, approximately every 8 hours. Process conditions within the cells are generally manually controlled. All vitrification instrumentation is logged to a central control room an interlock system is provided to trip the vitrification process if pre-set conditions are exceeded. 

From an early date in the conception of the MTR, a centralized control room was planned for the control and instrumentation of the reactor and its major cooling processes.. This arrangement is desirable since the materials of construction permit the operation of the reactor only as long as proper coordination of the heat removal processes, is maintained. However, this plan for centralization was changed by recent determinations that the time element, gained by control of the major reactor-cooling process from the reactor control center, would not facilitate the operation of the reactor. With the admission of this premise into the basis of design for the reactor control center, the requirements for simplifications of control problems have resulted in other locations for the controls of the heat removal processes. 

With modern instrumentation and automation of control equipment, and ever improving methods of data presentation, visual and audible alarms, etc., most plant operations are now controlled from the Central Control point. The reactor is designed to be capable of shutting itself down, inside preset limits of the plant conditions of the transient, by multiple lines of automatic protection. The Operator s role is therefore not critical in this respect. However, he must ensure that the plant is operated safely, efficiently and economically. 

In general, there are relatively few processes which cannot be made completely automatic. There are few manually operated processes which do not use instrumentation for indicating and recording. Processes may be started, stopped, or adjusted manually from a central control station by the use of remotely controlled equipment. 

The assembly station will be manned by personnel assigned to perform specified duties. These personnel are trained to use radiation detecting instruments, to read personnel badges, and report the results throng direct telephone hookcq) to the central control center. They will report pertinent information received from tee evacuees about injured personnel and unusual circumstances observed while leaving the building. 

Centralized control approach. DCS, distributed control system ESD, emergency shutdown system HMJ, human—machine interface MIS, management information system PU, pro cessing unit SIL, safety integrity level SIS, safety instrumentation system. 

Along the corridor of the power line, a system control and data acquisition (SCADA) or instrumentation line is run back to the main control station. Telephone wires or fiber optics are used to monitor remote start or shut pumps and valves. The computer system that monitors the local control may be programmable local controller (PTC) based. The centralized control room is usually called the distributed control system (DCS). SCADA controlled systems are designed to include ... 

PVC product is a voltage conversion component specially developed for control and propulsion system. It supplies power for the control and propulsion systems, such as the central control unite, gyro, momentum wheel, SADA, earth sensor, sxm sensor, promoting power amplifier, etc. It is a certain type of key instrument directly related to the normal working of a certain satellite platform. Because of its high life and reliability requirement, the conventional test methods are not suitable for it. ALT of the PVC mainly including the following several aspects ... 

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