Instrumentation monitoring control systems

Downing, T.M. Preparing for New Smokestack Monitoring Regulations," Instruments and Control Systems, 47 (Febtuaty 1992). 

The final component we need to consider is the instrumentation and control system (Figure 14-10). Good instrumentation is vital to ensure that an extrusion line is operating efficiently and to troubleshoot extrusion problems. Because we cannot see inside the extruder, nor would we leam much even if we could, instrumentation serves as a window onto the process. Monitoring an extrusion system has been compared to monitoring a patient in the hospital you always need to measure vital signs, like blood pressure and body temperature. Likewise, an extrusion line that is not properly monitored can... 

The instrumentation and control system was built for remote monitoring and control capability. Sensor outputs were visually observed as well as recorded. A 1-in. linear potentiometer was used to measure shaft position and a 6-in. linear potentiometer was used to follow shaft excursions during rapid cycling. When platform instead of shaft drive was used, platform position was determined by multiplying the measured travel time by a known... 

Nuclear instrumentation and control systems present a greater challenge. Even though it may be possible to develop a system that is inherently controlled by temperature for all normal operations, it appears that it will always be necessary to include control devices and instrumentation in the nuclear system to adequately control and monitor startup from cold shutdown, total shutdown, and possibly to compensate for fuel bumup. Design configurations that reduce the number and complexity of these instrumentation and control systems and components need to be developed. 

Instrumentation and control systems are required to monitor key parameters (for example, temperature, pressure, agitation, cooling) and take corrective action when a hazardous condition is detected. (See also case histories Al 57-61, pages 184-185.)... 

Instrumentation and control systems are provided for monitoring and controlling the major process variables related to each equipment and UOP, as shown in the process flow... 

The purpose of the instrumentation and control system (Fig. 2.14) is to measure and control important processing parameters. Without the data provided by this system, it would be very difficult to maintain a safe and efficient process and to troubleshoot extrusion problems. The data provides a window to the process, since we cannot see inside the extruder (and probably would not find it very useful if we could). Monitoring an extrusion line has been likened to monitoring a patient in a hospital we certainly want to measure the patient s vital signs, such as body temperature and blood pressure. Similarly, we need to monitor extrusion parameters, so the system does not become unstable, leading to a dangerous situation or to the production of costly scrap. 

Based on the tried and tested standard components of the SIMATIC range, the system offered is highly flexible and can be used in a distributed configuration in stable housings and can be moved from location to location. The integrated instrumentation and control system ensures safety by means of reliable monitoring and alarm functions. 

The instrumentation and control systems in the PHWR plant include a variety of equipment intended to perform display, monitoring, control, protection and safety functions. The concepts presented form the basis for the system design and development. General guide-lines followed are ... 

The instrumentation and control system consists of the reactor protection system, engineered safety features opmtion system, plant control system and reactor monitoring system. The reactor protection syston has two diverse shutdown ems. The engineered safety features are the decay heat removal system (PRACS) and the containment system. 

Microcomputer-based subsystems are standard in most computer control systems available today. The digital subsystems are interconnected through a digital communications network. Such systems are referred to as distributed digital instrumentation and control systems because of the network approach used to monitor and control the progress. 

The plant building schematic is shown in Fig. III-8. The plant includes instrumentation and control systems a system for heat removal to consumers an auxiliary power supply system and a radiation monitoring system, including process radiation monitoring, dosimetric monitoring, and environmental monitoring. 

A maintenance program involving both operating and maintenance personnel can help to ensure continued safe operation of an instrumentation and control system. The program should include preventive maintenance supported by systematic monitoring of system behavior. Any observed abnormalities should be reported and investigated as quickly as possible. The maintenance program should provide for ... 

A complete disconnection of the instrumentation and control systems are avoided since essential interlock and monitoring control and alarm functions are still needed, such as ... 

This section should provide relevant information on the instrumentation and control systems as described in paras 3.65-3.70. The reactor instrumentation senses the various reactor parameters and transmits appropriate signals to the control systems during normal operation and to the reactor trip systems and engineered safety features and systems during anticipated operational occurrences and in accident conditions. The information provided in this section should emphasize those instruments and their associated equipment that constitute the protection systems and those systems rehed upon by operators to monitor plant conditions and to shut the plant down and maintain it in a safe shutdown state after a design basis accident. Information should also be provided on the non-safety-related instrumentation and control systems used to control the plant in normal... 

A safety grade instrumentation and control system [9] should be provided to activate the appropriate safety systems and to provide sufficient information to reactor operators to enable them to determine the state of the RCSASs [11], The instrumentation and control system should be capable of continually monitoring plant conditions during normal plant operations as well as in anticipated occurrences. 

The instrumentation and control system of the JRR-3M consists of its constituent systems of neutron instrumentation, process instrumentation, reactor power control, reactor protection, engineered safety feature stating and process radioactivity monitoring The system is designed and constructed under the laws, standards and criteria of those days with a satisfactory quality assurance program A specific feature of the system is an extensive introduction of computer systems with a process computer and a management computer This contributes to lightening operators loads satisfactorily... 

Monitoring and control of the production process will be performed by a combination of instrumentation and control equipment plus manual involvement. The level of sophistication of the systems can vary considerably. For example, monitoring well performance can be done in a simple fashion by sending a man to write down and report the tubing head pressures of producing wells on a daily basis, or at the other extreme by using computer assisted operations (CAO) which uses a remote computer-based system to control production on a well by well basis with no physical presence at the wellhead. 

The safe operation of a chemical process requires continuous monitoring of the operation to stabilize the system, prevent deviations, and optimize system performance. This can be accomplished through the use of instrumentation/control systems, and through human intervention. The human element is discussed in Chapter 6. Proper operation requires a close interaction between the operators and the instrumentation/control system. To a large extent, batch operations have simple control systems and are frequently operated in the manual mode. The instrumentation system is the main source of information about the state of the process. Some of the typical functions of the instrumentation/control system are... 

The lime feeding system may be controlled by an instrumentation system integrating both plant flow and pH of the wastewater after lime addition. However, it should be recognized that pH probes require daily maintenance in this application to monitor the pH accurately. Deposits tend to build up on the probe and necessitate frequent maintenance. The low pH lime treatment systems (pH 9.5 to 10.0) can be more readily adapted to this method of control than high-lime treatment systems (pH 11.0 or greater) because less maintenance of the pH equipment is required. In a close-loop pH-flow control system, milk of lime is prepared on a batch basis and... 

Computer monitoring and control systems have recently been introduced. These are designed to operate in place of conventional instrumentation. Using intelligent interface outstations connected to a desktop computer, many plant functions may be programed into the computer and controlled centrally. 

Instruments are provided to monitor the key process variables during plant operation. They may be incorporated in automatic control loops, or used for the manual monitoring of the process operation. They may also be part of an automatic computer data logging system. Instruments monitoring critical process variables will be fitted with automatic alarms to alert the operators to critical and hazardous situations. 

Scattering on the Triple-Axis-Diffractometer [1,2] at the HASYLAB high-energy beamline BW5 is performed in the horizontal plane using an Eulerian cradle as sample stage and a germanium solid-state detector. The beam is monochromatized by a singlecrystal monochromator (e.g. Si 111, FWHM 5.8 ), focused by various slit systems (Huber, Riso) and iron collimators and monitorized by a scintillation counter. The instrument is controlled by a p-VAX computer via CAMAC. 

Process control plays an important role in how a plant process upset can be controlled and subsequent emergency actions executed. Without adequate and reliable process controls, an unexpected process occurrence cannot be monitored, controlled and eliminated. Process controls can range from simple manual actions to computer logic controllers, remote from the required action point, with supplemental instrumentation feedback systems. These systems should be designed such as to minimize the need to activate secondary safety devices. The process principles, margins allowed, reliability and the means of process control are mechanisms of inherent safety that will influence the risk level at a facility. 

Basic Process Control System (BPCS) - Pneumatic, electronic, hydraulic or programmable instruments and mechanisms that monitor and/or operate a facility or system to achieve a desired function, i.e., flow control, temperature measurement, etc., which are supervised by human observation. 

Most of the monitoring instruments specified in the GATS design package are simple and reliable, having been used extensively in the chemical industry. Control valves and monitors for temperature and pressure, as well as distributed control systems and PLCs, have also been widely used in industry. 

Flow schematics for the designed (layouts) water system showing all of the instrumentation valves, controls, and monitors, numbered serially... 

The original GC control system took the form of a central room which monitors the flowllne6, oil, water, and utility sections, plus a smaller satellite control room monitoring the gas compression and gas conditioning section of the plant. Closed loop process control, such as separator liquid level, pressure, flow and temperature control were handled by local pneumatic analog controllers. The key process variables are displayed in the control room via electronic instrumentation. All the key process and equipment trouble alarms are annunciated m the control rooms, plus the on/off status of key machinery and open/close status of key valves are displayed. 

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