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ISA Transactions Volume 45, Number 1, January 2006, pages 6775

0ased SCADA integration using the GPRS or WAP transfer scheme could enhance the performance of the crane in a dayithout causing an increase in the response times of SCADA functions. The operator can visualize and modify the plantarameters using his mobile phone, without reaching the site. In this way maintenance costs are reduced androductivity is increased. 2006 ISAThe Instrumentation, Systems, and Automation Society.

eywords: SCADA; Automation; Mobile phone; WAP; GPRS

. Introduction

The term supervisory control and data acquisi-ion SCADA was first introduced in the 1960s atonneville Power Administration and was firstublished in the PICA Power Industry Computerpplications Conference Proceedings. TheCADA system is used for monitoring and con-

rolling of industrial processes from remote areas.he need to monitor the process and possibly con-

rol the operation of industrial systems from virtu-lly anywhere is becoming an important issue.owever, with different types of platforms used inresent SCADA systems, incompatibility has be-

clude cost, security, accessibility, system integra-tion, data integrity, and consistency 2.

Many companies are considering SCADA sys-tems to provide access to real time data display,alarming, trending, and reporting from remoteequipment by using different communication me-dia such as Internet, private leased line PLL,dial-up connection, satellite, and radio modem.Recent technological advances have made locationtransparency achievable through the Internet at arelatively low cost and acceptable level of secu-rity. Some of the potentially valuable develop-ments are Intranet and Extranet. Nowadays, im-provements in the visual interface of the SCADAMobile phone based SCAEngin Ozdemir

Kocaeli University, Technical Education Faculty, Electrica

Received 5 August 20

bstract

SCADA is the acronym for Supervisory Control Andustry for supervisory control and data acquisition ofotebook, thin client, and PDA as a client. In this paperample SCADA application in order to display and suresents an actual implementation of the on-line controommunication between the mobile phone and the SCADome the main obstacle 1. Other problems in- Gr

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*Tel: 90 262 3032248; fax: 90 262 3032203. E-mailaddress: eozdemir@kou.edu.tr

E-mail address: mkaracor@kou.edu.tr

019-0578/2006/$ - see front matter 2006 ISAThe Instrumentatfor industrial automationevlut Karacortion Department, 41380 Umuttepe Kampus, zmit, Turkey

cepted 25 May 2005

ta Acquisition. SCADA systems are widely used intrial processes. Conventional SCADA systems use PC,a-enabled mobile phone has been used as a client in athe position of a sample prototype crane. The paper

of the prototype crane via mobile phone. The wirelessver is performed by means of a base station via generalUI Graphical User Interface have fairly high-esolution graphical animations.

In spite of all these improvements, a need hasmerged to access system information instead ofontrolling it from specific control centers.

ion, Systems, and Automation Society.

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68 E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775CADA systems have been opened to the worldia the Internet to meet this requirement. Despitell these improvements, the SCADA system needs

computer connected to the Internet. Recentlyhere has been a growing trend towards personalomputers and work stations becoming portablend mobile. This has led to a big expansion ofireless networking, which is getting advanced in

erms of technology and usage and penetration 3.SCADA software usually exists in a computer,hich carries out tasks of supervision and man-

gement of alarms, as well as data processing androcess control. The communication is made byeans of special buses or LAN networks. All

hese tools are executed normally in real time, andre designed to give the plant operator the possi-ility of supervising and controlling of these pro-esses.

SCADA systems require both hardware andoftware for their successful execution. User-esigned control parameters, graphical system dia-rams, trend charts, alarm screens, and program-able control logic are some of the features of the

oftware program for the SCADA systems. Thisaper discusses the use of mobile phone as a clientor an industrial SCADA automation system. Anxperimental prototype crane system is monitoredy a mobile phone in a sample SCADA applica-ion. An attempt is made to provide some insightnto design considerations for wireless mobilehone based automation as used in modernCADA automation systems. It is emphasized thatith some basic knowledge of design consider-

tions, it is easier to take the right automation ap-roach and choose the right equipment for the taskonsidered. Test results have indicated that theobile-based SCADA integration using the gen-

ral packet radio service GPRS or wireless ap-lication protocol WAP transfer scheme couldnhance the performance of the crane in a dayithout causing an increase in the response timesf SCADA functions. As distance to remote sitesncreases, it becomes more difficult to accesshem. In this case, SCADA becomes a better alter-ative to an operator or repairman visiting the siteor adjustments and inspections. Distance and re-oteness are two major factors for implementinghe SCADA systems. T. Review of conventional SCADA system

SCADA is used to observe and supervise thehop floor equipments in various industrial auto-ation applications. SCADA software, working

n DOS and UNIX operating systems used in the980s, was an alarm-based program, which has aairly simple visual interface.

SCADA systems using a variety of RTUs re-ote terminal units are used for industrial control

nd supervision all over the world. These systemsrastically cut operating costs and allow the auto-atic supervision and reporting needed in todays

egulatory environments. The main components ofconventional SCADA system 35 are RTUs at

ubstations and plants, data processing units, andan-machine interfaces MMIs. ConventionalCADA system components are given in Fig. 1here all monitoring, processing, and control are

onstrained within the local area network locatedn the control center. Dedicated channels are re-uired to guarantee the time responsiveness of theystem.In earlier days, an alarm sounding at control

oom meant that a crew would be dispatched tohe trouble site to assess the problem. Based onheir assessment, other crews would be called in,nd those crews often would discover that yet andditional work crew was needed. Insufficient dataith no control meant that all alarms were treated

s urgent, since there was no knowledge about themportance of an alarm or the attention it required.

Fig. 1. Conventional SCADA system components.oday, when an alarm goes off at a new SCADA

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69E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775ontrol center, an operator calls up a screen thathows the exact problem. The operator quickly de-ermines the importance of the alarm and simply

akes an adjustment or, if necessary, dispatcheshe appropriate crew directly to fix the problem.CADA now provides monitoring of the entire au-

omation process, including the treatment facili-ies. Presently, full control functions are beingmplemented in the SCADA automation system.CADA systems allow equipment in many differ-nt locations to be monitored and controlled fromcentral location.With the advances of electronic and software

echnologies, the supervisory control and data ac-uisition systems are widely used in industriallant automation. It provides an efficient tool toonitor and control equipment in manufacturing

rocesses on-line. The SCADA automation systemlways includes several functions, e.g., signalensing, control, human machine interface, man-gement, and networking.

. Web based network architecture

A typical SCADA system architecture is shownn Fig. 2. In this architecture, data systems are onhe highest level, used for planning and storingata. The programs, including the server and clientsed by the operator and system, are on the MMI

Fig. 2. Typical SCADA system architecture.evel. The PLC and RTU level is responsible for she connection between sensors and actuators inhop floor 6,7. In this level, there is program-able logic controller software that controls shopoor equipment in a design manner.The basic components of a web access based

CADA system are shown in Fig. 3 8. Web en-bled SCADA hosts enable users to remote moni-or and to control remote sites via a web browser.osted SCADA services allow users to monitor or

ontrol their remote equipment by using a normaleb browser and logging onto a secure website.Typically, a web access based SCADA system

ontains five elements. These are SCADA nodes,lients, project nodes, thin client, and network.he SCADA node communicates in real time withutomation equipment. Typical automation equip-ent includes programmable logic controllers

PLCs, single loop controllers, direct digital con-rol systems DDC, distributed control systemsDCS, and input/output I/O modules. A full ani-ation client uses an ActiveX control inside an

nternet Explorer web browser to view real-timeata, acknowledge alarms, and change set points,

ig. 3. The basic components of a Web access basedCADA system.tatus, and other data. The client then communi-

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70 E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775ates directly with the SCADA node using propri-tary communication links over a TCP/IP networkonnection. The project node is a centralized data-ase server. It can be physically separated fromhe SCADA node or combined with it. A copy ofhe database of all SCADA nodes is kept on theroject node. Remote configuration and graphicsuilding occur on the project node using a Weberver to exchange data with remote clients. Theonfiguration of database and graphics are thenownloaded to the SCADA node from the projectode, which is a web server. The thin client inter-ace supplies static snapshots of graphics as GIFles. No plug-in or ActiveX control is required.he thin client is intended for use with PDA,ocket PCs, and handheld computers but otherSP enabled web browsers can view the graphics.eal-time data, alarms, and changes to data areerformed by means of a text-type interface. Thehin client does not communicate with theCADA node directly, it communicates directly to

he project node only. Then network supplies theonnection between the nodes and clients. AnyCP/IP network including local area networks

like Ethernet, a corporate Intranet, the Internet,r dial-up connections can be used. Internet andeb based SCADA systems have a lot of advan-

ages, such as a wide area connectivity and perva-ive, routable, parallel polling, redundancy, andot standby, large addressing range, integration ofT to automation and monitoring networks, andtandardization.Many companies consider using the Internet for

CADA to provide access to real-time data dis-lay, alarming, trending, and reporting from re-ote equipment. However, there are three signifi-

ant problems to overcome when implementing annternet based SCADA system. The first is thatost devices used to control remote equipment

nd processes, such as gas production wells andower distribution systems, do not have Internetommunication capability already incorporated inheir operating systems. The second is that the de-ices still have to be physically connected to thenternet, even when equipped through retrofit or inhe factory with the necessary communicationsrotocols. These problems must be solved at lowost and high reliability before Internet basedCADA can be implemented in industrial automa-

ion applications. The third is assurance of the data

rotection and access control. One solution to ihese problems is to connect the device to a PCnd have the PC make the connection to the Inter-et via an Internet service provider using secureocket layer. Unfortunately, this solution may noteet the low-cost criterion, and depending on con-guration, can lack reliability. An alternative tosing a PC is an embedded solution, a small, rug-ed, and low cost device that provides connectiv-ty capabilities of a PC at lower cost and highereliability.

The open nature of the Internet requires dataecurity measures when implementing Internetased SCADA systems. Processes, procedures,nd tools must address availability, integrity, con-dentiality, and protection against unauthorizedser. The open architecture of Internet basedCADA system combined with appropriate fieldquipment makes it possible to develop an inte-rated system such as mobile phone. However, in-eroperability requires data format and transmis-ion protocol standardization. Use of Internetased SCADA automation system to monitor andontrol a plant has been proven to improve pro-uction and lower maintenance costs.The introduced Java based application for a

CADA system was created with networking,ompatibility, and support for an open geographi-al distributed environment as its main objectives.

consistent GUI for SCADA systems will enablenexperienced operators to become proficient in itssage with minimal training, thus reducing theost requirement to invest in training staff on so-histicated and hard-to-configure systems.A SCADA system gathers incoming automation

ystem data for further processing by a number ofistributed processes. However, existing SCADAnformation management systems cannot satisfyhe new challenges as more and faster informationas now become desirable by many users andlayers. Technological advances in networkingave made it possible to develop a low cost com-unication system for accessing real-time power

ystem information over digital network.With a Java based application, any Java enabled

rowser can be used to view and control theCADA system from any terminal of any existingperating platform within the control center. Thepplication is platform independent, portable,here system data can be shared, reused, and ac-

essed at a much-reduced cost. As the application

s downloaded from the Web based server system

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71E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775nto the client system for execution via a Webrowser, scalability and performance are no longerightly tied to the Web based server system. Higherformance requirements have also been ad-ressed through multithreading in the application.his new Java based application, when applied to

he SCADA system, provides an easy, effectivend low investment means of accessing data. Nopecial hardware is needed for the setup.

. Developed application

In order to test the developed system, a modelrane, which can move in two directions by usingwo dc motors, is designed. The model crane isontrolled by using Siemens S7 300-312 IFM PLCd SM334 I/O card. A CP5611 MPI bus card ob-ains the data interface between PLC and server.he SCADA program is WinCC, and the mobilehone is Siemens M50 containing 228-Kb usertorage and is used for the proposed Java applica-ion.

The whole system consists of the model crane,he PLC with the control panel, mobile phone, and

PC. All the components of the mobile phoneased SCADA application are shown in the pho-ograph in Fig. 4. The model crane has three sen-ors, two of them are used for left-right directionnd one of them is used for crane height.The basic components of this model system aremodel crane, computer, Siemens S7-300 CPU

12 IFM PLC, and SM 334 AI4/AQ2 I/O card.he crane can turn itself around 360 and can act

n the y axis. The movements of the crane can beontrolled by using two dc motors. The PLC haseen used as a bridge, which provides data trans-er between the server and the test equipment. The

ig. 4. Photograph of the mobile phone based SCADApplication.ost important part of the control action proce- pures is carried out by small programs in SCADAoftware. Data exchange between the server andLC are realized by MPI bus protocol via aP5611 MPI bus card installed on the server com-uter with a 187.5-KB/s data exchange rate. Theobile-based SCADA application model system

lock diagram is illustrated in Fig. 5. The serveronitor and SCADA screen shot, and the remote

ontrol and remote supervision program screenhots are shown in Figs. 6 and 7, respectively.Mobile phone SCADA GUI screen shot is

hown in Fig. 8. The mobile phone client GUIas four specifications graphical animations,alue tables, alarm page, and remote control ashown in Fig. 9. The parametric values of the pro-otype application are converted to graphical ani-

ations and listed in the value tables. Alarms thatccured in the prototype application are given inhe alarms section. Remote control of the applica-ion is carried out by using the remote controlage.The J2ME Application Program JAP operating

Fig. 5. Mobile based SCADA application block diagram.

ig. 6. The server monitor and SCADA screen shot of test

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72 E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775n mobile phone is prepared in Sun One Studio 4.he program has been tested in the Siemens M50mulator and then downloaded to the mobilehone. The user can access the real-time informa-ion superimposed on on-line diagrams generatedutomatically using the mobile phone and routingechniques through the Internet. In addition, theser can control the operation of the automationystem with the mobile phone through GSM glo-al system for mobile base stations. The choice ofhe Java technologies offers unique and powerfuleatures such as zero client installation, on-emand access, platform independence, and trans-ction management to the design of the on-lineCADA display at the mobile phone.

. Design of the mobile phone based SCADAystem

External data communication and integrationrom various information sources such as controlenters, power plants, and substations have be-ome a necessity. As more and more real-time in-ormation is being desired by many customers andendors, existing information management sys-

ig. 7. Remote control and remote supervisor programscreen shots.Fig. 8. Mobile phone SCADA GUI screen shot.ems cannot satisfy the new challenges. Distrib-ted SCADA has already become the trend of theuture industrial automation system development.

In operation of the mobile phone based applica-ion, SCADA software in the server is operatedrst. Afterwards, the SCADA controlling programSCP, which realizes the process of sending datao the server side program SSP, is operated.hen, it transfers the data reading from theCADA database to the Web page designated,here the ASP active server page is responsible

or setting up the connection between the mobilehone and the SCADA system. The simple quan-ities of data received by the ASP, sending fromCP found in the Web server, is stored in the ASP.This information reaches the ASP by means ofPRS or WAP after JAP in the mobile phone and

his information is saved in the JAP database. Ana-yzing the data in this database, the JAP turns itnto a value diagram, bar graph, text message, andarious graph animations, which can easily be un-erstood by the operator. As long as the programn the mobile phone operates, data between the

obile phone and SCADA system are automati-ally exchanged. The proposed mobile phoneased SCADA automation system includes sixevels as shown Fig. 10.

1. There are three servers in the first level:Web server, the master server, and the re-serve server.

2. Firewall software or specially designedcards are used to ensure data security in thesecond level.

3. The operator station or control room, that

Fig. 9. Mobile phone client GUI specifications.contains PCs or thin clients, are installed at

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73E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775the central location in the plant. In the pro-posed system, a Java-enabled mobile phoneis included as a client into the SCADA sys-tem.

4. Remote operator stations that can be con-nected to main server by its competence areused to inform the operator at the centralcontrol room. In todays SCADA applica-tions, the number and the location of opera-tor stations are not limited by means of In-ternet connectivity.

5. PLC and other controllers, which are verynear to the central control room, are placedin this level. The communication is realizedby cables between PLC and other control-lers to the central control room.

6. RTU, Internet based equipments, and othercontrollers that are very far away from cen-tral control room are placed in this level.The communication media that are used inthis level are private lease lines and radiomodems.

7. Sensors and actuators are placed the lowest

ig. 10. The proposed mobile phone based SCADA auto-ation system.level of the SCADA automation system. u. Designed software architecture

Internet/Intranet has been successfully em-loyed in many areas for real-time applicationsuch as audio stream and videoconference. Annternet-based SCADA system was also intro-uced 9 into a power system. Several prototypesnd products have been introduced for on-lineCADA applications. However, most of the exist-

ng SCADA applications were set up based on theonventional computer technologies. An importanthallenge is how to integrate new services and net-ork elements into the existing system. In this

ection is described an Internet based informationccessing system based on an existing SCADAystem.The designed software architecture consists of

hree different programs: mobile phone program;erver side program SSP; SCADA controllingrogram SCP.

.1. Mobile phone programThe mobile phone program is designed by using

2ME Java Micro Edition downloaded to a mo-ile phone with GPRS general packet radio ser-ice or WAP wireless application protocol. Therogram sends the data required for the web servern accordance with the protocol using preferablyPRS or WAP internet access technology, re-

eives the data sent by web server, and informs ito the user with the help of graphical interfacenalyzing this knowledge in its structure.The application routine has two stages. At the

rst stage, current and voltage values of the sys-em, state of motor 1 and motor 2 ON/OFF, anducket position value are sent to the mobile phonerom the SCADA server. The data received by theobile phone are interpreted by the J2ME appli-

ation and some related graphical animations areffered to the user. At the second stage, an autho-ized user can control the SCADA system valuesia the mobile phone by using its user name andassword. In our case study, authorized users canontrol the state of motor 1, motor 2, and the sys-em on/off position by using the J2ME applicationrogram in the mobile phone.

.2. Server side programA Server side program SSP can be designed bysing any server side script ASP, PHP, etc. or

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74 E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775ava Servlet Server Applet. In this application,SP is used as a SSP in order to get fast response

o a lower number of users than Java Servlet thatupports excessive users. It receives the requestata sent by the program integrated into the mo-ile phone. It reads the values belonging to thetate or position database located in the computern which the web server is installed. These data areent to the mobile phone via Internet in accor-ance with the program in the mobile phone andhe protocol between them 1012.

.3. SCADA controlling programsThis program is installed in the same computerith the SCADA system and has a visual inter-

ace, receives the data pertaining to the state of theystem connecting with SCADA, and saves it tohe condition-stating database in the computer inhich the web server is installed. Two differentrograms have been designed and used to monitornd control the SCADA system via mobile phone.he remote control program mobile to SCADAas been used to control the SCADA system viaobile phone, while the remote supervisor pro-

ram SCADA to mobile has been used to moni-or the SCADA system via mobile phone. A dataow diagram of the designed model system soft-are architecture is illustrated in Fig. 11.TCP/IP offers reliability by providing

onnection-oriented, end-to-end reliable packetelivery through an Internet network. It does thisy sequencing bytes with a forwarding acknowl-dgment number that indicates to the destinationhe next byte the source expects to receive. Bytes

ig. 11. Data flow diagram of the designed system softwarerchitecture.ot acknowledged within a specified period are re- sransmitted. The reliability mechanism of TCP/IPllows devices to deal with lost, delayed, dupli-ate, or misread packets. A time-out mechanismllows devices to detect lost packets and requestetransmission 13.

. Conclusion

In this study, a Java enabled mobile phone haseen integrated into the SCADA system as a cli-nt. Therefore the obligation of the SCADA sys-em to work with a PC is not necessary. Since the

onitoring and control of the plant process is per-ormed with the use of present GSM base stations,o cost of network setting is required. The ex-hange of data with the SCADA system is accom-lished through GPRS or WAP, so the expendituref connection is considerably low.The conditions in a process plant of an automa-

ion system are harsh and the site is remote. Re-ources for data communication are difficult to ob-ain under these conditions; thus a wirelesshannel communication through a mobile phone isractical and efficient in a process control environ-ent. The mobile communication industries and

he public have a strong interest in the WAP tech-ology application in mobile phone networks. TheAP API application program interface in

ower industry applications is one of the areas thatequire extensive investigation. The objectives ofhis study are replacing the existing conventionalCADA system with one new mobile based sys-

em to control the sample crane, increasing theCADA attain envelope to include all of the loca-

ions not currently reached, providing a SCADAystem with WAP based software applications, anderforming these purposes by installing minimumew hardware.SCADA systems are alarm based systems and

hese alarms are monitored and controlled by anperator in a control center to inform maintenanceperators when needed. This type of conventionallarm management system can be affected by hu-an based faults. Integrating the mobile phones of

he maintenance operators to the SCADA systemsan minimize these faults. The maintenance anduthorized operators can monitor and also controlhe system with their java enabled mobile phonesy using their user name and password. Thelarms occurring in the system can be sent to theuthorized personnel or operators as a SMS mes-

age so that system security can be maximized.

Response time of the mobile phone based systemir

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SCADA applications. IEEE Trans. Ind. Appl. 9 2,12951334 1997.

75E. Ozdemir, M. Karacor / ISA Transactions 45, (2006) 6775s set to 10 sec, that can be changed by the user asequired. In addition, the user can also get infor-ation about the SCADA system whenever theyant.By using a mobile WAP phone, shop floor per-

onnel have access to critical information wher-ver they may be, and can take corrective action intimely manner. Instead of being chained to a

omputer terminal, plant engineers and automa-ion professionals now enjoy a new tool that offersreater mobility, thus making workers more pro-uctive, while maintaining the ability to monitorhe integration of real-time data, alarm, and his-orical information in everyday plant operations.s distance to remote sites increases, it becomesore difficult to access these sites. ThereforeCADA becomes a better alternative to an opera-

or or repairman visiting the site for adjustmentsnd inspections. Distance and remoteness are twoajor factors for implementing SCADA systems.The mobile phone based SCADA automation

rovides a cost effective solution to control andutomate of the flow of information for small toedium size process plants. The proposed mobile

hone based SCADA system has the capability ofeporting selected process values and equipmentlarms, giving GUI about process, remote control-ing, and refreshing process data in a user-etermined timely manner.

cknowledgments

This research was supported by TUBITAK Re-earch Project Project No. EEEAG 101E002.he authors wish to express appreciation to M.dem Sengul for his cooperation and help in all

he Java software programming of this work.

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2 Ong, Y. S., Gooi, H. B., and Lee, S. F., Java-basedapplications for accessing power system data via In-tranet, extranet and Internet. Int. J. Electr. Power En-ergy Syst. 23, 273284 2001.

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10 Sun Micro Systems, http://www.sun.com/nc/whitepapers, The Java Enterprise Server PlatformWhite Paper.

11 Sun MicroSystems, http://www.sun.com/nc/whitepapers, Implementing Java Computing SolutionsWhite Paper.

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13 Internetworking Technology Overview, June 3012,1999.

Dr. Engin Ozdemir was born inIzmit, Turkey in 1970. He re-ceived his Ph.D. degree in Electri-cal Engineering from KocaeliUniversity in 1998. Since 1999,he has been an Assistant Professorin the Department of ElectricalEducation, Faculty of TechnicalEducation, Kocaeli University, inTurkey. His research interests areindustrial automation systemsPLC, SCADA, etc., power elec-tronics, and fuel cells.

Mevlut Karacor was born in Es-kisehir, Turkey in 1977. He re-ceived his M.Sc. degree in Elec-trical Education from KocaeliUniversity in 2004. He is cur-rently a Research Assistant andPh.D. student in Technical Educa-tion Faculty in Kocaeli Univer-sity. His research interests are re-mote control and industrialautomation systems PLC,SCADA, etc..