International Journal of Emerging Technology and Advanced Engineering Website: (ISSN , Volume 2, Issue 7, July 2012)

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1 Introduction of PLC-Based Remote Laboratory for Modular Mechatronics System (MMS) Amriya Tasneem H. R. 1, Dr. K. R. Prakash 2, S.N. Ravi Shankar 3 1 Department of Mechanical Engineering, Malnad College of Engineering, Hassan , Karnataka, INDIA 2 Special Officer, VTU-Bosch Rexroth Centre of Competence in Automation Technology, Mysore , Karnataka, INDIA 3 Department of Mechanical Engineering, Malnad College of Engineering, Hassan , Karnataka, INDIA Abstract The proposed work describes programmable logic controller (PLC) based feasible and cost-effective remote laboratory platform for modular Mechatronics system. This is a multidisciplinary laboratory which gives the knowledge about PLC programming skills, mechatronics, automation technology and working principle of various robots, sensors, actuators, controllers, mechanisms, drives etc.., of the system which are usually used in industries. The laboratory also provides opportunity for students to program and build their control circuit to control the system via internet. The mms has three stations used to assemble the metal and non-metal cubes with two pins using pneumatics press and stored in the rack, this system consists of three different types of pneumatics robots. The process of manufacturing or assembling the cubes will be divided into sub-systems or small experiments to build the logic and executing it. The logic is built using Rexroth IndraWorks Engineering Software and students can even follow the operation or working of system using Team Viewer software via internet. This remote laboratory concept helps the student to feel them as if they are working in real industrial equipments and or environment. The present work can be used as web-based laboratory with internet for distance education. Keywords Distance education, mms, PLC, Rexroth Indra Works Engineering, Team viewer, Web-based laboratory. I. INTRODUCTION The mechatronics system is a synergistic integration of fundamental elements of mechanical engineering, electronic engineering, intelligent computer engineering, software engineering, control engineering and system design engineering in design and manufacture of products and processes in a powerful, adaptable and interdisciplinary approach. In a mechatronics laboratory usually students are provided with different types of sensors, valves, actuators, switches, controllers etc.., which are used to build their own control circuit to a given design task. Students can easily learn the subject and understand when they involve in experiments than compared to theory classes. 328 The Programmable Logic Controller (PLC) is a type of controller used to control robots which plays a vital role in today s automation field. The main purpose of PLC is to replace hundreds and thousands of hard wired relays. The PLC can be programmed and controlled using ladder diagram which is easy to learn and write. But employing this type of highly sophisticated laboratory facility is almost impossible for many institutions due to high initial cost. The invention of internet technology acted as a catalyst to implement new teaching methods. The remote laboratory concept is one among them, which is increasingly being in demand now-a-days. The remote laboratory is considered as a competitive service or solution or alternative in industries for remote measurement, supervision, diagnosis and control. From an educational point of view, a distance and e-learning system could play an important role in providing help for university teachers to teach distance education course or web-based laboratory. These laboratories have been used as an alternative method of teaching in many institutions all around the globe or worldwide. In [1], a distance PLC programming course for flexible manufacturing cell using remote laboratory concept is described. The control is implemented over internet using Axis 205 network camera software. In [2], a virtual laboratory to control liquid levels in tank using PLC ladder logic via internet remotely. In [3], the web-based environment for color identification experiment. The control is achieved over internet using client-server architecture with Transmission Control Protocol/Internet Protocol (TCP/IP). In [4], the remote laboratory for internet-based engineering education based on PLCcontrolled temperature and flow processes experiment equipment to those in biochemical industries. The control is achieved using Omron proprietary command/ response protocol. In [5], the remote control of a robot is described and controlled using client-server architecture with User Datagram Protocol/ Internet Protocol (UDP/IP).

2 In [6], the project-based laboratory for electrical drive control using PLC programming and remote laboratory concept. In [7], the design and implementation of PLCbased monitoring control system for Induction motor experiment controlled using internet. In [8], the remote laboratory for optical circuits control using Lab view tool via internet. In [9], the remote and virtual robotic laboratory and controlled via internet using client server architecture. In [10], the current trends in remote laboratories, author concentrated on application of mechanical and electrical engineering fields to implement remote laboratory concept. From the recent literature survey, the widespread of remote laboratory concept is adopted in almost all the engineering disciplines that are automation, robotics, power electronics, electrical drives, control, mechatronics etc.., using different types of software through internet. This paper describes the development and implementation of remote laboratory platform for robotics based on PLC in modular mechatronics system using Team Viewer software via internet. The structure of this paper is as follows: the section-2 includes remote laboratory setup, remote laboratory architecture in section-3, in section-4 the discussion of various experiments available, and concluded in section-5. II. REMOTE LABORATORY SETUP Remote laboratory facilitates the student to access the laboratory during 24*7 hours a week. The student can easily connect to laboratory whenever required from wherever they wish to access the laboratory. This laboratory provides more flexibility for students to learn and use laboratory using internet. The laboratory can be viewed through camera placed to monitor the system which gives the feeling that as if they are working in real laboratory equipments and it is not as those of virtual and simulative type of laboratory. The system allows the connection of three different users connected simultaneously to the three different PLCs. The block diagram describes the scheme of remote laboratory and communication network to achieve remote control over laboratory via internet is shown in fig. 2. A. Modular Mechatronics System The mechatronics system is called as modular because it is divided into three stations or modules. The mms is as shown in fig. 1 is the system to be controlled. This system must assemble two cubical halves with two tension pins using pneumatic press. The mechatronics system is called as modular because it is divided into three stations or modules. The fig. 2 represents the arrangement of stations to form modular mechatronics system. This system assembles two cubical halves i.e. one is metal and another one is non-metal with two pins using pneumatic press. The system can be controlled both in automatic and hand mode, the mms is composed of three stations or tables performing different tasks are as follows, 1. Station-1: Magazine Station: The first station [fig. 3(a)], consists of two magazines, a conveyor belt and a testing unit. Metal and non-metal cubes are stored separately in two magazines, when start button is actuated the metal cube will be ejected out of magazine on to the conveyor using pneumatic cylinder. When sensor senses the presence of cube on the conveyor, conveyor starts to move in forward direction. Testing unit consists of four sensors namely, capacitive, inductive, depth detective and optical sensors to detect the presence of cube on conveyor, material type and its orientation to accept or reject material (sorting the material). 2. Station-2: Press Processing Station: It consists of a cylindrical robot, turning unit, pining section, pressing unit, portal robot and a conveyor as shown in fig. 3(b). The pick-and-place robot picks the cube from conveyor of station-1 and places into pining unit for pining purpose then into pneumatic press. The portal robot after assembly transfer material to the conveyor. 3. Station-3: Storage Station: The station-3 [fig. 3(c)], consists of a handling robot, a Cartesian robot (encoder) and a rack to store finished products one-by-one sequentially. B. Programmable Logic Controller (PLC) The system is controlled with PLC (Rexroth IndraControl L20, supplied by Bosch Rexroth, Germany). Each station has its own PLC, which must control the manufacturing sequence and communication between the other stations. The PLCs have several input-output modules which includes digital inputs and outputs, analog inputs and 329

3 Station-2 Station-1 Station-3 Fig. 1: Modular Mechatronics System Fig. 2: Scheme of the mms laboratory setup and communication network 330

outputs and counting modules. The students/remote user have to program the PLCs using some of the different languages defined in the IEC61131-3 standard.

(CFC). The software employed to develop logic is Rexroth Indra Works Engineering Software. III. REMOTE LABORATORY ARCHITECTURE The remote laboratory architecture is as shown in fig.

The client or student PC is connected to server PC of laboratory via internet using team viewer software. The client-server architecture is implemented to achieve this remote laboratory concept.

It also allows user for file transfer and distance presentation purpose but only between connected PC s via internet.

4 outputs and counting modules. The students/remote user have to program the PLCs using some of the different languages defined in the IEC standard. The different languages available are Structured Text (ST), Instruction List (IL), Ladder Diagram (LD), Function Block Diagram (FBD), Sequential Function Chart (SFC) and Continuous Function Chart (CFC). The software employed to develop logic is Rexroth Indra Works Engineering Software. III. REMOTE LABORATORY ARCHITECTURE The remote laboratory architecture is as shown in fig. 4, the server PC is connected with PLC of modular mechatronics system (mms) using Ethernet cable and webcamera. The client or student PC is connected to server PC of laboratory via internet using team viewer software. The client-server architecture is implemented to achieve this remote laboratory concept. (a) (b) Fig. 4: The Remote Laboratory Architecture A. Remote Laboratory Development Tool The Team Viewer is a type of software which allows users to share their desktops screen. It also allows user for file transfer and distance presentation purpose but only between connected PC s via internet. The client/student who wish to use remote laboratory need not to have Rexroth Indra Works Engineering software installed in their PC as users can use the software installed in server PC. But they are supposed to have the membership in team viewer. The students, who need to connect, should know the login-id and password of server PC. Then they can access server PC files, software and program the PLC of the system. The view of desktop sharing when connected with team viewer software is as shown in fig. 5. (c) Fig. 3 Stations of modular mechatronics system. (a) Station 1: (b) Station 2: and (c) Station 3. IV. REMOTE LABORATORY EXPERIMENTS Initially students are thought with basic theoretical aspects of pneumatic actuators, drives, sensors, PLC programming, automation technology, controllers and communication techniques between systems. They are made to learn how to configure the PLC and its inline I/O modules used, PLC programming using different languages for simple exercises and to work with the different kinds of variables, inputs, outputs, timers and counters. As Team Viewer software allows for distance presentation purpose. In presentation mode up to 25 members of students/remote user can connect to laboratory platform, where student/remote user can listen to the presentation rather than controlling the laboratory equipment. 331

5 After ensuring that they have the required knowledge about the mms, the tasks are given and students are supposed to develop remotely the control of one of the three different sub cells. Students should actuate their logic first in simulation mode and then they should load the program to PLC, this avoids the damages going to occur due to wrong program. After correcting the program, they can download it to flash card of PLC and system will run according to written program. Sharing the computer or PC which is going to connect can be controlled by setting the level of privacy. The stations of mms are divided into small experiments/projects/tasks to reduce the complexity in programming the system using PLC for students. The experiments sub-divided from each station are as follows: A. STATION-1 (Magazine station) a. Ejection of material Task: When start button is actuated the cylinder-1 should retract first then extend and retract again to push cube from magazine on to the conveyor. If the start button S1 is actuated when sensors B1 is ON and emergency stop button in OFF condition the cylinder-1 Y1 will extend. And when sensor B2 is ON then cylinder-1 will retract. Metal and non-metal cubes stored in the two magazines and two pneumatic cylinders are as shown in fig. 6. The solution is in the form of control circuit or ladder logic written to achieve the given task or objective is as shown in fig. 7. Similar to the above example/experiment all the below experiments will have task/question with respective inputs and outputs. The students should write the logic using these inputs and outputs for given task using any of the PLC languages. b. Movement of conveyor c. Testing unit for sorting the material d. Rejection of material e. Acceptance of material B. STATION-2 (Press Processing Station) a. Picking of material to keep the material in turning unit or in press directly by robot b. Turning unit control c. Working of pneumatic press d. Control of gantry robot e. Control of conveyor f. Controlling the rotation of robot g. Control of vaccum sucker C. STATION-3 (Storage Station) a. Control of handling robot 332 b. Rotation of robot up to encoder c. Movement of encoder d. Controlling encoder to store finished product in the rack properly and sequentially. After completing the above experiments students can combine the small tasks of each station to complete station- 1, station-2 and station-3. Finally they can program for whole of mms by combining the program of three stations. V. CONCLUSION The present paper introduces remotely controllable robots of modular mechatronics system platform used as a web-based laboratory to teach technical students. Especially mechanical, electrical, computer science, electronics engineering students about mechatronics, automation technology, PLC programming skills and makes them to acquire basic knowledge in the field, allowing them to work with some of the common situations of industry. This laboratory is more flexible than tradition laboratory because it has no time limit and gives the student more practical experience. REFERENCES [1] O.Gomis, D.Montesinos, S.Galceran, A.Sumper, and A.Sudria, A Distance PLC Programming Course Employing A Remote Laboratory Based On A Flexible Manufacturing Cell, IEEE Trans. Educ., Vol. 49, pp , May 2006 [2] D.Perdukova and P.Fedor, A Virtual Laboratory For The Study Of Mechatronics, 9th IEEE International Conf. on Emerging elearning Tech. and Appl.(ICETA), pp , Oct 27-28, 2011 [3] Wen-Jye SHYR, Development And Evaluation Of Mechatronics Learning System In A Web-Based Environment, TOJET: The Turkish Online Journal of Education Technology, Vol. 10, Issue 1, pp , Jan-2011 [4] Ahmed Chiheb Ammari and Jaleleddine Ben Hadj Slama, The Development of a Remote Laboratory for Internet-Based Engg. Education, Institute National des Sciences Appliques et al Technologies (INSAT) pp [5] B.Aktan, C.Bohus, L.Crowl, and M.Shor, Distance Learning Applied To Control Engineering Laboratories, IEEE Trans. Educ., Vol. 39, No. 3, pp , Aug-1996 [6] Coia Ferrater-Simon, Lluis Molas- Balada, Oriol Gomis-Bellumunt, A Remote Laboratory Platform for Electrical Drive Control Using PLC, IEEE Trans. Educ., Vol. 52, No. 3, pp , Aug-2009 [7] Maria G. Ioannides, Design and Impelemientaion of PLC-Based Monitoring Control System for Induction Motor, IEEE Trans. Energy Cons., Vol. 19, No. 3, pp , Sept [8] Deniz Gurkan, Alan Mickelson, and Driss Benhaddou, Remote Laboratories for Optical Circuits, IEEE Trans. Educ., Vol. 51, No. 1, pp , Feb 2008 [9] Costas S. Tzafestas, Nektaria Palaiologou and Manthos Alifragis, Virtual and Remote Robotic Laboratory: Comparative Experimental Evaluation, IEEE Trans. Educ., Vol. 49, No. 3, pp , Aug-2006

6 [10] Luis Gomes and Seta Bogosyan, Current Trends in Remote Laboratories, IEEE Trans. Industrial Electronics, Vol. 56, No. 12, pp , Dec-2009 [11] W.Bolton, Programmable logic controllers, fifth edition, published by Elsevier, a division of Reed Elsevier India Private Limited. [12] Rexroth IndraLogic L20 System Description, Operating and Programming Guide R Edition 01 [13] Rexroth IndraControl L20 System Description, R Edition [14] Rexroth Bosch, Understanding the IEC programming languages, Drive and Control News letter, (2009). [15] Rexroth Bosch, mms-station-magazine Manual, RE09952-B

The Modular Mechatronic System from Rexroth. Practise-orientated, efficient, ready to use

The Modular Mechatronic System from Rexroth Practise-orientated, efficient, ready to use Learning as in Real Life Just as the tempo of innovations cycles is constantly increasing, so do the demands on