Supervisor Control And Data Acquisition

Introduction, main points of report and Conclusion

It is not an abstract, nor is it part of the Introduction. Should be considered a separate stand-alone section that summarises all major points of the report.

Introduction  

The problem or maintenance approach being addressed

Context of the problem/ maintenance approach

Methodology

Results and discussion

The SCADA is a computrelized communication system that can monitor the process, transmit, and displays using graphical user interfaces for the whole industry operation data in the controller. SCADA uses programmable logic controllers and discrete (PID) Proportional Integral Derivative Controllers to access the interface monitored. SCADA concept was to enable and enhance universal accessibility remotely without the need of great workforce being required to control industries operating systems and machines. The systems were first  put into trials in the 1960s. It supports the industry with the ability to be able to monitor and control its system remotely and locally, gather real field data in real-time and keep the records of event occurrences much more efficient and on real-time. The SCADA systems are paramount to most of the industries so as to be effective, avoid breakdowns, process data much smartly and show system state and condition. Example SCADA system can give the industrial operator warnings in case of emergency, and it gives him the exact condition of the machine temperature, batch being transported like in a pipeline. The SCADA also shows the amount of pressure that is exerted in bars, and the operator will know the best action to maintain the system safely at the remote level or locally if it's required to be rectified or controlled at the ground (Daneels & Salter, (1999)

Before the invention of the SCADA, industries struggled to monitor and control their production process which became harder by the day. Industries started trying every means to curb the tiresome and costly production means by use of relays and timers as means of supervisory control without the need of workforce in the field. The relay and timers became absolute since they were hard to reconfigure, they were unable to diagnose faults and most especially industries with the time required more efficient and automated technology and that led to the birth of the SCADA system. First generation (Monolithic) SCADA system was used in the 1960s and computed using the minicomputers. At the time SCADA was invented common network was not also available, and so the system was also independent therefore there was no connectivity to other systems. Second generation (Distributed) SCADA system was connected to multiple stations through LAN where each of the stations had different tasks which minimized the cost of operation as of that of the first generation (Ten et al. (2008).

Both the first and the second generation network protocols were still not standardized. The third generation (networked) system was spread across to more than one LAN network known as the Process Control Network, and it was also separated geographically where few SCADAs were running parallel to each other with only one supervision. The third SCADA system reduced the cost of operation and enhanced efficiency for large firm systems. The Fourth generation (internet of things) SCADAs significantly adopted Internet mode of operation cutting a lot of expenditure on the infrastructure and reduced the maintenance cost. SCADA system in the fourth generation operated in near real-time state and with the help of cloud computing more complex control algorithms was implemented to the traditional PLCs. Due to the decentralization of data SCADAs required to be enhanced so as to be able to bind all the information from different PLCs memory addresses and avoid problematic issues when data from different sensors or controllers are feed to the system. The solution to this problem was through data modeling (Karnouskos & Colombo (2011).

Results and Discussion

 The SCADA system is made up of hardware and software materials which function are the hardware receives or taps the information from the interface and transmits it to the computer where now the software interprets the information to complete data information or records.  The software part of the SCADA mainly serves different purposes according to the type of information delivered to the computer from a primary source. Example if a signal is received in the system like the emergency stopping of pump generator it sounds the alarm immediately. SCADA mainly comprises Supervisory Computers, Remotely terminal units, Programmable logic controllers, communication infrastructure and Human-interface.

Supervisory computers act as the brain of the SCADA system where it processes the information and sends the commands to the installed devices. Supervisory computers are the software part which helps in the processing of data received and responsible to the sending of information or communication purposes into the computer and also to the field devices which are connected to the controllers. The filled connection controllers are the Programmable Logic Unit and Remote Terminal Units and

Remote Terminal Units (RTU) usually connects to the sensors and motors or machine in the industry. RTUs are known to of intelligence and are designed with control capability such as ladder logic that can be able to accomplish Boolean logic of operations.

Programmable Logic Unit (PLCs) are networked to the supervisory computer the same as to the connection in RTUs, and they are connected to the sensor and motor or machine in processes. PLCs have greater control capability as compared to RTUs; it’s programmed to one or several programming languages. PLCs are more used than RTUs because of several reasons that are; first PLCs are more economical than RTUs, PLCs have more flexibility, versatile and have better configuration than RTUs. One of the main great difference between PLCs and RTUs is the ability of PLCs and disadvantage of RTUs to support control algorithms or the control loops. Most of the companies that require monitoring or controlling motion, positioning and torques use PLC because of its ability not be affected by impacts and vibrations.  Some industries and companies set up motion controllers working together with PLCs to control machines movements and vibrations that may act disruption or affect the production process. The PLC model tapping to the system is normally done by connecting the input to the primary sensor and tapping the output to the final control device connected in the field.

A PLC is a real-time system this means that the output ratio results is directly proportional to the input injected into the system within a particular period. PLCs are designed for different task handling capabilities example is digital and analog inputs and outputs. The PLC are also designed with a prove free to some conditions such as high-temperature working ranges, electrical noises, and vibrations. PLCs have logic for various functions and program example integral, single analog feedback, analog control loop and derivative controller (PID). A PID loop is used to monitor and control temperature changes in plants. PLC has transited a lot in the changing of control loops which were very few and could be able to handle processes which required more hundreds or even thousands of loops and also to be more efficient than Distributed Control System (DCS).  PLCs modernization and continuous transition with has made the PLC system more effective and powerful than the DCS system (Macaulay & Singer (2011). PLCs memory of programs to control various memories and devices is stored up in non-volatile memory or normally to a backup system that has power storage to avoid the confusion and destruction in the system. Modern and many of the updated PLCs have control sequence that can respond automatically and reconfigure back to the defaults settings in the event of any failures in the communication system and thus provide undisrupted and safer operation of the firm (Goel, & Mishra, (2009).

SCADA Development Progress

Communication infrastructure is responsible for connecting the PLCs and RTUs to the Supervisory Computer system. The communication system sends commands to PLCs and RTUs for continuous running but RTUs and PLCs operate autonomously and near real-time control, so, therefore, there is communication. The industry process are not interfered with or disrupted; the critical industrial system has dual data network highways usually through cables or other diverse routes. The data collection from RTUs and PLCs are collected to one central unit which also is the primary database memory residence. The central unit of data collection is known as Master Terminal Unit that entails of one or several computers connected in actual data collection system. An example of field data that be received in an industry are; Analog signal which is a continuously changing value within a defined zero and span. Rate signals which are pulse value representing a measurable quantity over time within a defined zero and span, and Digital signal that is discrete of values representing the state of a device. The remote control of industrial processes using the SCADA system is called telemetry. Due to the increase of security demand in the communication system in the world, many of the industries and organizations have adopted or opt to use satellite-based communication. (Karlsson, et al. (2004).

Human-Machine Interface (HMI) is the display of the system using graphical user interface of high level. It provides the whole industrial operation schematic diagram which is in the form of a mimic diagram. The mimic diagram is schematic symbols, animations, digital pictures or images and lines that allow the operator idea of the whole structure. The HMI is linked to the supervisory computer and so to be able to collect live data feeds; it gathers information from devices in the field and processes it to a much reliable data display by showing trending status of the whole firm operational process and also issuing an alarm to any incident. The controlling of the system by the operator involves issuing of command remotely using the computer and mainly using the mouse to click on the screen. Example, an operator in oil industry observing a pipeline in an industry can close the valve to a tank if the floating sensor gives out the message that the reservoir is full and redirect the product to another tank, the actual operator can increase or decrease the liquid flow rate through increasing or decreasing the pressure bars. The HMI gives the alarming message and stable condition of the system by mostly color indication. The example most pipeline industries use red to indicate active processes and green for dormant processes. The representation can also be used in elevator control, train on the railway line and other many industrial monitored systems (Li et al. (2002).

The SCADA system virtually is at one point directly and indirectly in use to ease our daily to day life. The SCADA system is used in industrial organizations and companies in the private and public sectors to control and maintain maximum efficiency in the production and output ratio.  The system is one the relied technology in most manufacturing companies such as; energy, water and wastewater, food and beverage, manufacturing, recycling, etc. SCADA has numerous benefits that greatly saves many industries and companies a lot of time and money. An example is SCADA notifies the operator pipeline leakage or even it shows a malfunction on a machine and also giving the main course of the problem and how the operator is supported to do correct the situation (Zaher, et al. (2009).

SCADA Mode of Operation

The SCADAs have significantly contributed to the growth of Australia economy and industrial growth; transport sector also has a lot of benefits to the system. Example, the railway transport in Australia, mainly relies on the SCADAs to control how the train enters or leave the stations and also the airways transport have their system majorly based with SCADA system all over to have smooth control of the departures and arrivals. Another sector that SCADA act as a backbone pillar of the industry operation is the oil and gas sectors, the SCADA allows the transportation of the products over long distances and being controlled in one central point. The SCADAs are installed in every booster and deport stations of the company where the product is transported with very high pressure to the required destinations or the customers. The system is very reliable to the oil and gas industries because of the ability of the SCADA to monitor the pipeline and controls the entire line. (Endi, & Elhalwagy, (2010). Data collection of the SCADA is known to be much better because of its ability to gather real-time statistics from the field the RTUs, PLCs and other electronic measuring equipment gadgets that are positioned at an intervals in the pipeline. Communication between the gadgets might occur in several ways, where else most common media are devoted to phone circuits, terrestrial, and satellite-based radio programs. It shows leakages in the system and also controls the actuators in the opening and closing of the valves.  However SCADA has security vulnerabilities, this is due to the exposure to different types of the network thus also increasing different types attacks. SCADA is faced with multiple threat vectors such as access to unauthorized control software, software attacks by virus access in the system, destruction of SCADA devices by packet access through the network segment loopholes. And also the attackers get away through the system by VPN by bypassing to SCADA network jerk and switches this according to (Davidson, et al. (2006).

Conclusion:

The SCADA system is one the best efficient and reliable software that small and complex industries and companies rely very much on the production process. Australia is a developed country it’s faced with major industrial problems that come up every day. For our nation to have one the best efficient industrialization in the world, the country has to boost the industries and companies with the best SCADAs in the market that have a much-updated system. If the security vulnerabilities are looked upon SCADA system is a reliable software for companies, industries, and even our domestic homes. A good example of SCADA system impact to the society and the whole world is in the water transportation and treatment and also in the oil and gas industries, therefore, its true say that SCADA system is backbone pillar of our society, companies and all industrial organizations in general. This has been deeply discussed how SCADAs have contributed to the saving of resources and Energy by (Berry,  (2000).

Reference:

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