Touch Screen Technique for Learning PLC Programming

Wen-Jye Shyr Department of Industrial Education and Technology

National Changhua University of Education Changhua Taiwan, R.O.C.

E-mail:shyrwj@cc.ncue.edu.tw

Yu-Chuen Huang Department of Industrial Education and Technology

National Changhua University of Education Changhua Taiwan

Abstract This study presents a touch screen technique for instruction in the use of programmable logic controllers (PLC). Students used touch screen software and a program containing virtual processes simulation to develop their own applications, both in class and at home. The main contributions of this study are as follows: (1) A learning platform was developed and experimentally tested; (2) Exercises were specifically targeted to the learning of PLC programming; (3) The technical aspects of the proposed touch screen technique are presented.

Keywords Touch screen technique, programmable logic

controllers, PLC

I. INTRODUCTION Modern computer technology is becoming increasingly

important in education. One important benefit of computer technology in education is that the level at which learning occurs, and the permanence of that learning, can be increased [1]. It has been found that an engineering education, in particular, requires practical activities in a laboratory to apply the concepts and methods learnt in theoretical courses [2].

A wide range of methods have been used to write programs for industrial control applications and programmable logic controllers (PLC) [3]. Gomis et al. [4] used commercial PLC to automate a manufacturing cell and communicate with other systems. Hshieh and Hshieh [5] proposed a tutorial system for PLC.

Touch screen techniques facilitate the collection of data to save time in administrative duties, make the scoring and entering of data more convenient, and allow immediate access to results [6-7]. Touch screen interfaces are increasingly being used in industrial computer systems to replace the traditional keyboard or mouse. These systems employ a simple, direct interaction with graphical icons representing specific tasks [8].

This study developed teaching technologies for PLC that enable students to learn the system successfully. A simulator was integrated within the touch screen software, enabling students to program the PLC to control virtual processes.

II. TOUCH SCREEN TECHNIQUE

There are a variety of touch screen technologies that have different methods of sensing touch such as: Resistive, capacitive, surface capacitance, projected capacitance, mutual capacitance, and self-capacitance [9].

The proposed touch screen technique addresses the following pedagogical issues: (1) implementing PLC programs using touch screen software; (2) learning how to plan a project; (3) learning how to monitor processes; (4) grasping concepts related to PLC automation with an emphasis on the importance of standards, and (5) understanding how touch screen processes work.

The design of human machine interfaces has evolved considerably, particularly in the use of touch screen technology and SCADA (supervisory control and data acquisition) terminals [10]. These developments are expected to continue, fueled by advances in the multi-touch displays suitable for industrial use, such as those found in tablet PCs.

This study developed Vijeo Designer, a state-of-the-art software application that enables users to create operator panels and configure operating parameters for touch screen devices. It provides all of the tools required to design projects, from data acquisition to the creation and display of animated drawings. 2.1 Features

The Vijeo Designer employs two types of data: (1) internal data created in user applications, and (2) data provided by external devices such as PLC and remote I/O modules. Vijeo Designer enables the configuration of a human machine interface (HMI) capable of communicating with third-party devices simultaneously. Vijeo Designer also enables the creation of dynamic screens for the HMI, combining a range of functions, such as moving objects, zooming, and creating level indicators, on/off indicators, and switches. Animated symbols can be used to build and edit graphical screens very simply and a script feature enables the reuse of building blocks or full sequences for other projects.

2.2 Main screen

The main screen of the Vijeo Designer environment is presented in Figure 1.

III. SAMPLE EXPERIMENTS: ELEVATOR

3.1 Experiment 1: elevator Figure 2 presents the elevator flowchart, which is the basis

for the touch screen application. Table 1 presents the PLC contact point planning for the elevator.

2014 International Conference on Computational Science and Computational Intelligence

978-1-4799-3010-4/14 $31.00 © 2014 IEEE

DOI 10.1109/CSCI.2014.131

737

2014 International Conference on Computational Science and Computational Intelligence

978-1-4799-3010-4/14 $31.00 © 2014 IEEE

DOI 10.1109/CSCI.2014.131

253

2014 International Conference on Computational Science and Computational Intelligence

978-1-4799-3010-4/14 $31.00 © 2014 IEEE

DOI 10.1109/CSCI.2014.131

253

2014 International Conference on Computational Science and Computational Intelligence

978-1-4799-3010-4/14 $31.00 © 2014 IEEE

DOI 10.1109/CSCI.2014.131

253

Figure 1. Main screen of Vijeo Designer

Figure 2. Flowchart of elevator processing

3.1.1 Process

The user is expected to determine the position of the elevator in advance when the elevator is in the Power ON state. If the elevator is at the 1st floor, then the user can push

the 2nd or 3rd floor button. If the elevator is at the 2nd floor, then the user can push the 1st or 3rd floor button. If the elevator is at the 3rd floor, then the user can push the 1st or 2nd floor button. The M point resets when the elevator reaches the target floor.

PLC programming is used to control these elevator control processes. PLC has proven flexible, robust, and easy to modify and debug. The programs are developed using touch screen software and a simulator to provide HMI capability.

3.1.2 Simulation

The simulation function of the touch screen software enables the use of virtual laboratories without the need for additional software or hardware. A virtual process section is used to simulate the system.

3.1.3 Monitoring

The HMI utility of the touch screen software can be used to monitor the evolution of process variables with all of the components, including M point, motors, and buttons placed on a single screen (Figure 3).

Figure 3. Touch screen for elevator

3.2 Experiment 2: flashing racing lights

Figure 4 illustrates the flashing racing lights flowchart for the touch screen application. Table 2 shows the PLC contact point planning.

3.2.1 Process

In Figure 4, when power switch (X0 ) is on, only Y0 displays; 1 second later only Y1 displays; 1 second later only Y2 displays; 1 second later only Y3 displays; 1 second later only Y0 displays. The lights take turns shining until the student turns off X0.

3.2.2 Simulation

The simulation capability of touch screen software enables an experiment to construct virtual laboratories. The program sections created by the students read the information from the monitor.

TABLE 1. PLC contact point planning for elevator PLC Contact Point Function X0 Power Switch X1 1F Limit Switch X2 2F Limit Switch X3 3F Limit Switch X9 1F Push Button(PB) X10 2F Push Button(PB) X11 3F Push Button(PB) Y0 Motor forward(Elevator up) Y1 Motor reverse(Elevator down)

Floor Detect?

Up for 2nd floor or 3rd floor

Up for 3rd floor or down to 1st

floor

Down to 1st floor or 2nd

floor

Reset M point

1st Floor

2ndFloor

3rd Floor

Power on

738254254254

3.2.3 Monitoring

The HMI utility in the touch screen software monitors the process evolution. All the components, including X0 and Y0-Y3, are placed on a single screen (Figure5).

Figure 4. Flowchart of flashing racing lights

TABLE 2. PLC contact point planning PLC Contact Point Function X0 Power Switch Y0 Y0 displays Y1 Y1 displays Y2 Y2 displays Y3 Y3 displays

Figure 5. Touch screen for flashing racing lights

3.3 Final report

The students prepare a final report to be submitted to teacher. They have to include some of the programs they have carried out and some of their conclusions about the entire work. This very important step is the main source for the evaluation assessment of the students.

IV. ASSESSMENT

High-quality assessments have been shown to enhance the eagerness of students to exert themselves and improve individual learning attitudes. As students grow used to the assessment process, they continually assess themselves and other students [11]. User assessments tend not to be as well articulated and explored in terms of assessing whether a system is usable, or whether it actively increases work productivity.

System assessment enables the capture of information regarding student likes and dislikes, and whether or not the Vijeo system meets their needs. The proposed touch screen technique was tested and evaluated based on student assessments. Once the human machine interface platform was built, the outcome was evaluated. Student assessments regarding the effectiveness of the platform revealed whether the system accomplished its objectives.

An assessment form was employed to measure the usability of the platform; this assessment form was distributed to all students who took the PLC course in the Department of Industrial Education and Technology at National Changhua University of Education, Taiwan. Overall, the assessment was generally positive.

The author has created a laboratory manual for the course that includes laboratory assignments and discusses all necessary details of how to complete the touch screen tasks.

V. CONCLUSIONS

This study developed a touch screen technique for learning PLC incorporated with a simulator. The software can be used by students during class and at home to control virtual processes. The use of this software can help students to learn the fundamental concepts related to automation, which will prove essential to their careers. Using the software, students might learn how to program PLC as well as the means to structure a general automation project. Results of this study indicate that the proposed touch screen technique is a power tool for learning PLC. The students were able to grasp the benefits of the platform once they understood what they were doing and which devices they were dealing with. The use of a touch screen enabled instructors to adjust the course structure and enabled students to develop programs and explore solutions implementation problems.

ACKNOWLEDGMENTS

This work is based upon work supported by National Science Council, Taiwan, Republic of China under grants NSC 102-2511-S-018-014.

Power ON

only Y0 displays

delay 1 second

only Y1 displays

delay 1 second

only Y2 displays

delay 1 second

only Y3 displays

delay 1 second

739255255255

REFERENCES [1] R.E. Clark, T.G. Craik, Interactive Multimedia Learning

Environments, NATO ASI Series F: Computer and System Sciences, 93, Springer, 1992.

[2] A.N. D'Andrea, F. Giannetti, G. Manara, M. Michelini, P. Nepa, A Virtual Educational Laboratory for Telecommunications Engineering, International Journal of Engineering Education, vol.24, no.1, 2008, pp.144-152.

[3] G.B. Oriol, M.M. Daniel, G.A. Samuel, B.J. Joan, S.A. Antoni, A Chemical Process Automation Virtual Laboratory to Teach PLC Programming, International Journal of Engineering Education, vol.23, no.2, 2007, pp. 403-410.

[4] O. Gomis, D. Montesinos, S. Galceran, A. Sumper and A. SudriaÁ, A Distance PLC Programming Course Employing a Remote Laboratory Based on a Flexible Manufacturing Cell, IEEE Transactions on Education, vol.49, no.2, 2006, pp.278-284.

[5] S.J. Hshieh, P.Y. Hshieh, Animations and Intelligent Tutoring Systems for Programmable Logic Controller Education, International Journal of Engineering Education, vol.19, no.2, 2003, pp.282-296.

[6] M.C. Greenwood, A.J. Hakim, E. Carson1, D.V. Doyle, Touch-Screen Computer Systems in the Rheumatology clinic Offer a Reliable and User-Friendly Means of Collecting Quality-of-Life and Outcome Data from Patients with Rheumatoid Arthritis, Rheumatology, vol.46, 2006, pp.66-71.

[7] M. Veit, A. Capobianco, D. Bechmann, An Experimental Analysis of the Impact of Touch Screen Interaction Techniques for 3-D Positioning Tasks, IEEE Virtual Reality Conference, 75-82, 2011.

[8] P. Kaszycki, Touch Screens are Now Used on the Majority of Industrial OIT or HMI Devices in a Variety of Applications, Touch-Screen Technologies Offer Ease of Use Reliability, Control Solutions, vol.75, no.1, 2002.

[9] A. Sears, C. Plaisant, B. Shneiderman, A new era for high-precision touchscreens. Advances in Human-Computer Interaction, vol. 3, Hartson, R. & Hix, D. Eds.,1992.

[10] M. Scholz, HMI trends in industrial touch screens, HMI at Kontron, 2013.

[11] K. Isbister, K. Höök, J. Laaksolahti, M. Sharp, The Sensual Evaluation Instrument: Developing a Trans-Cultural Self-Report Measure of Affect, International Journal of Human-Computer Studies, vol.65, no.4, 2007, pp.315-328.

740256256256