Instrumentation supervisory control

Microprocessor-based control systems are marketed under a variety of acronyms and not all will be true DCCSs. Of particular note are the Supervisory Control and Data Acquisition (SCADA) systems which form an increasingly central part of the operations of many industries (e.g. offshore oil and gas platforms, petrochemical complexes, pulp and paper works). SCADA describes a communications system whose principal function is to join instrumentation and control into a cohesive package(57) and, particularly, the supervision and management of remote ... 

Data acquisition is provided by instrumentation. Chemometrics, on-line prediction, and reporting are typically supported by some kind of Supervisory Control And Data Acquisition (SCADA) system and/or Manufacturing Execution System (MES). This may be a COTS product or a custom development. Data Historian is likely to be a separate interfaced application. To support this and exchange of information with other systems an open systems approach should be adopted. 

All capsule pipeline systems include a pipe, many capsules, an injection system to inject capsules into the pipe, a pumping system to pump the fluid and capsules through the pipe, an ejection system to eject the capsules from the pipe, an instrumentation system to monitor the flow rate, pressure, temperature, and the passage of capsules at key locations, and an automatic control system that uses programmable logic controllers and an SCADA (Supervisory Control and Data Acquisition). 

An interface to the Fieldbus instruments, providing the OCS with the necessary data to perform supervisory control. Note that some control is performed at the level of the intelligent instruments themselves, and the control system downloads set points, monitors the control and records the various parameters. 

Supervisory control refers to the role a human plays in operating a semiautomatic process or system. Examples include control of large systems such as a nuclear power plant and specific instrumentation such as a robotic or assistive device. Performing supervisory control is high-level task that predominantly consists of mental components. This task is used to generically illustrate the use of analytic techniques to model a task. 

Instrument records are authoritative because they are objective and quantitative. Facilities that use SCADA (Supervisory Control and Data Acquisition) or DCS will generally have a large amount of instrument data that can be readily accessed. 

Control System (BPCS), including functions of Supervisory Control and Data Acquisition (SCADA) system, the alarm system (AS) and Safety Instrumented Systems (SIS) performing defined Safety Instrumented Frmetions (SIF). Proper design of layers of protection is based on hazards analysis and risk assessment with consideration of human and organizational factors. It is essential to ensure required safety integrity level (SIL) for each of these layers. 

Fig. 28.1a-c. Technical classification of robotic systems a Supervisory controlled system, in which the surgeon plans the operation off line and the robot performs the specified motions autonomously under the supervision of the surgeon, b Telesurgical system, in which the robot is under direct control of the surgeon with an on-line input device, which is typically a force feedback joystick (master), c Shared control system, in which the robot and surgeon share control of the surgical instrument. [Modified from Nathoo et al. (2005) with permission]... 

Fiset, J. 2009. Human-Machine Interface Design for Process Control Applications. Research Triangle Park, NC Instrumentation, Systems, and Automation Society. Written for designers and industrial control personnel, this book discusses three basic human-machine interfaces distributed control systems (DCSs), supervisory control and data acquisition system (SCADA), and stand-alone units. 

However, these assumptions were incorrect. The worker decided to rely on the trip and stopped watching the level. The supervisor and foreman knew this, but were pleased that the worker s time was being utilized more productively. A simple trip fails about once every two years so the tank was bound to overflow after a year or two. The trip was being used as a process controller and not as an emergency instrument. The operating and supervisory staff probably assumed a much higher level of reliability for the trip than was actually the case. 

Does the customer s management fully understand what is required from their side and can they actually deliver the necessary supervisory and manpower support For example, changing from a system of simple chemical dosing pumps to a microprocessor-controlled product residual tracing and addition system will probably require more equipment inspection and calibration time. It will also require a high degree of instrumentation skill. 

A pilot plant can be computer controlled in one of two ways supervisory or direct digital control as shown in Fig. 10. In the first, a computer supervises another primary control element. In the second, the interfacing element is eliminated and the controller (e.g., a valve) is regulated directly. New computer-based automatic instrumentation is likely to be supervisory because it is faster and less expensive. (See also Refs.P - l.)... 

Programmable controllers are specific microcomputers that are designed to replace electromechanical relay logic systems. These instruments can be connected to computers for data logging or the computer may act in a supervisory capacity over the programmable controller. 

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