Supervisory Control and Data Acquisition SCADA

The design of the Supervisory Control and Data Acquisition (SCADA) system is integral to the performance of the system, in terms of safety, efficiency, and effectiveness. SCADA systems essentially have two main roles  

Communicating information from physical sensors within the plant 

Facilitating physical manipulations of components within the system 

Descriptions of the controlled system can be presented at a number of levels of abstraction. These descriptions range from physical raw data from individual sensors up to higher order systems performance descriptions calculated through data fusion. SCADA has been around in one form or another for as long as the systems they represent and control have. Early SCADA systems were comprised of a series of readouts directly hardwired to the physical objects they represented. These hardwired display consoles were generally large, fixed, and difficult to modify. The advent of the microchip has allowed many of these systems to be digitized. It is now possible to remotely control these systems with mechanization, computers, and appropriate software. 

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Determination of critical assets that might be subject to malevolent acts that could result in undesired consequences What are the malevolent acts that could reasonably cause undesired consequences on these assets electronic, computer, or other automated systems that are utilized by the public water system (e.g., Supervisory Control and Data Acquisition (SCADA)) the use, storage, or handling of various chemicals the operation and maintenance of such systems... 

Intrusion through Supervisory Control and Data Acquisition (SCADA)... 

System interface with hardware supervisory control and data acquisition (SCADA) program... 

Control of the field occurs on two levels. The upper level Is the supervisory control and data acquisition (SCADA) system whose main responsibility is well flow rate control, well testing, production allocation, accounting and general field monitoring. The SCADA system is operated from the Main Operations Center (MOC) which is remote from all three GCs. The second level of control is process control in the individual GCs. Flow to the GCs Is normally controlled by the SCADA system (HOC operator), but the GC operator can override and control well flow rates in case of SCADA system failure or other unusual circumstances. The GC operator and the MOC operator communicate via a dedicated telephone connection. 

Since the operation is in an arctic environment, achieving the above objectives presents particular problems and would be difficult and Inefficient using the more conventional approaches. Therefore, as part of the original facilities a "supervisory control and data acquisition" (SCADA) system was Installed in the VfOA. The operational philosophy is one where, by means of the SCADA system, the functions necessary for reservoir management and production control could be monitored and controlled from a central location called the Main Operations Center [Pg.57]

The crude oil delivery system starts with relatively small-diameter gathering lines from individual producing wells to a main-line pump station, from where it is pumped through a larger transmission trunkline to a refinery or other destination. At the refinery, the cmde oil is separated into gasoline, jet fuel, kerosene, distillate fuel oil, etc, and the refined products are transported by products pipelines to markets, storage, shipping terminals, etc. In modem lines, all inputs and outputs are metered, monitored, and remotely controlled by supervisory control and data acquisition (SCADA) computer systems. 

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 ... 

Stand-alone systems. Multiloop controllers) or programmable logic controllers (PLC) typically used to control part of a process, and larger supervisory control and data acquisition (SCADA) systems/distributed control systems (DCS) used to control the process or service as a whole (e.g., bulk primary production plant, building management systems). These self-contained systems are a component of an automated manu-... 

Incorrectly implemented calculations moving averages in Supervisory Control and Data Acquisition (SCADA) systems, material mixing concentrations in DCS systems, flawed shelf-life date calculations in Laboratory Information Management Systems (LIMS). 

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. 

The vahdation of analytical methods that are based on arrays of sensors cannot rely on the traditional pharmaceutical approach. Many of the vahdation headings have no equivalent, and important steps, such as vahdation of software, are not explicitly included. The pharmaceutical industry does, however, have a model for vahdation that could be used in modern analytical chemistry, namely the vahdation of programmable logic controllers (PLC) [26] and supervisory control and data acquisition (SCADA) [27] systems. This was the subject of a recent issue of the journal Measurement and Control [1]. Of importance is now the process of vahdation, which may be broken down into a number of steps (Fig. 1). 

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. 

Association service control element This module is a supervisory control and data acquisition (SCADA) element related to the ISO/lnternational Electrotechnical Commission (lEC) 15953 and 15954 standards. No MMOs are transmitted in this stage. 

A checklist is industry specific and is developed with the help of experience and plant history data. There may be generic checklists for certain types of major equipment but in industry it is unique in the sense that a checklist for supervisory control and data acquisition (SCADA) applicable for an electrical transmitting system may not be applicable for SCADA in oil and gas midstream plants. Similarly, a checklist for a nuclear plant may not be applicable for a fossil fuel power plant. Here, may not be means that the turbine operation part of the nuclear plant may be utilized for the fossil fuel power plant as well. However, the checklist of a refinery will be completely different. 

The logic elements may be distributed, linked by communications, or marshaled together and may be in the form of distributed control systems (DCS), supervisory control and data acquisition (SCADA), computers (including PCs), or PLCs. 

Modem networked supervisory control and data acquisition (SCADA). Dl, device 1 DN, device N lED, intelligent electronic device Int., intelligent I/O, input/output. 

Prior to the widespread implementation of supervisory control and data acquisition (SCADA) and human-machine interface (HMI) systems, most SPC and SQC was performed by quality-control departments as an off-line process. Data was collected from test stations, laboratories, etc. and statistical analysis was performed later. SCADA/HMI systems, however, have made it feasible to provide plant-floor SPC charts using data collected in real time directly from the process. Fabricators that want to standardize SPC and SQC to increase their use find they need the two following functions (1) provide the plant floor with SPC charts and (2) make data collected by SCADA systems available for off-line analysis. Available is SPC and SQC software to support these efforts. Recognize that the bulk of SPC s value is derived from process improvements developed from offline SQC analysis. 

The Olympic pipeline was controlled using a supervisory control and data acquisition (SCADA) system - in other words, a digital control system. This system used plant sensors and actuators connected to two DEC VAX computers, with one primary computer, and one backup. The computers received data from the sensors and the actuators every 3-7 seconds. As is normal for systems like this, the operators used screens with pre-programed formats on which the data were displayed, and the operator could interact with the system by mouse click. The system also recorded and stored all data and commands made. 

Although the formal design of the control room should be conducted by an architect, it is possible to perform a rudimentary evaluation or feasibility study based on the required contents of the room along with an understanding of expected traffic flow. The design of the room should always be driven by the requirements of the operators rather than the physical constraints of the room. In most cases, the first step is to determine the required size of the operator s workstation (see Section 10.5.1.2) which is in turn informed by the Supervisory Control and Data Acquisition (SCADA) system housed on the workstation. Next, the number of required operators should be considered based on the workload (see Chapter 6). The arrangement of these workstations will be dependent on the required level of conununication (see Chapter 4) as well as the required level of supervision (see Chapter 8). Other important factors to consider include the orientation of displays due to environmental considerations such as windows and the potential confusion that could arise from operators determining the ownership for audible alarms. 

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