programming and testing of storage conveyor in a virtual
Contents
1. a Gl amp amp BS ce Al Symbols 1 __ Status Symbol Address ja Box in FC 1 1 Box out FC 2 FC 2 Fetch Box out control FG 3 FC 3 control out Stop Pressure FC 4 FC 4 Stop is Pressure Identify Color FC 5 FC 5 Color ID Counters FC 6 FC 6 State of storage level Full Not full S6 20 BOOL IN OUT Conveyor S1 21 BOOL Elevator 1 Left 1S2 22 BOOL Elevator 1 Right PS10 23 BOOL Elevator 1 M 1 PS9 24 BOOL Elevator 1 Ivl 2 PS8 25 BOOL Elevator 1 lvl 3 PS7 26 BOOL Elevator 1 Ivl 4 1 S3 l 27 BOOL Storage Ivl 1 Left 84 30 BOOL Storage M 1 Right S8 34 BOOL Storage Ivl 2 Left S9 l d BOOL Storage lvl 2 Right S10 33 BOOL Storage Ivi 3 Left sd Press Fl to get Help NUM E Figure 18 Symbol Table 4 2 7 User program creation Implementation of Blocks The user program was created with FBD language and stored as blocks The program is divided into different parts to help in reading and under standing A block is a section of the user program which is defined by its function structure or its intended purpose Berger 2005 96 The different block type used in this program includes OBs and FCs 25 Programming and testing of storage conveyor in a virtual environment Organizational block OBs These blocks serve as an interface between the operating system and user programs Berger 2005 96 OBs used in this program are OB1 and OB100 OBI is2. The user s manual was designed to provide instructions to users on how to use the model It provides step by step guidance on the use of the model The user s manual can be used from any location as long as the model is accessible 5 4 2 User requirements The requirements of the user are as follows The user must have general knowledge about a computer The user must have basic STEP 7 programming skills The user must be able to operate in a virtual environment 5 4 3 Writing the user s manual The following steps were considered when writing the user s manual The user of the manual Some reasonable assumptions where made about the user based on the user s manual requirements for example the skills level of the user The format of the user s manual The manual is simple and not too technical to understand Pictures and texts were used to explain the procedures in details Model features The model features were well explained and broken down into smaller parts in the user s manual Model operation The operational procedures of the model were clear ly stated 5 4 4 Access to the user s manual The user s manual is available here in appendix 1 It is also available at the web link provided 31 Programming and testing of storage conveyor in a virtual environment 6 CONCLUSION A PLC program was successfully designed with STEP7 to automatically control the model The model units were working pro
3. The procedures for programming a real machine differs slightly from the ones stated above 4 3 1 Hardware requirement The hardware requirement of real machine programming includes Acomputer PC STEP 7 software MPI interface for the PC PC Adapter PLC SIMATIC 57 300 with digital In and Output device 27 Programming and testing of storage conveyor in a virtual environment ASTEPT 3 PC Adapter 4 S7 300 Figure21 S7 Hardware requirement SIEMENS 4 3 2 Real machine programming procedures Design the program structure The program structure should be de signed beforehand This allows the automation task to be examined thoroughly before the real programming Create a new STEP 7 project A new STEP 7 project should be cre ated as described earlier Configure a station This is the specification of the programmable controller that is desired to be used Example SIMATIC 300 Configure hardware This involves specifying the modules to be used for the automation solution in a configuration table Configure networks Create subnets for your automation networks set network connection properties and other connections required for the networked stations Symbol table creation this is same as described in section 4 2 6 Creation of user program and definitions The user program is cre ated using any of the available programming language The program created is linked to a module and stored as blo
4. J SIMATIC Manager S7_Pro100 C Program Files x86 Siemens Step7 s7proj S7_Pr iux Bp File Edit Insert PLC View Options Window Help la x Dg E X Baix S t EE E E NoFit sd cB 57 Pro100 E SIMATIC 300 Station 3 gl cPustart sq S7 Program 1 Bg Sources g Blocks Press F1 to get Help Figure 16 STEP7 OBI appears in the window 4 2 5 Program structure The program structure shows the call hierarchy structure The program structure of the user program can be seen in appendix 3 In this program the organisational block OBI is the master controller program Figure below shows the program structure 24 Programming and testing of storage conveyor in a virtual environment ENG e Figure 17 The program structure 4 2 0 Symbol Editor Symbol editor is used to assign symbols to signals and other variables The symbol table contains variable definitions which are used in the pro gram and the model The variables include inputs outputs functions memory bit and memory word It shows symbol names addresses data type and comments A symbol can only be used once on the symbol table Easy to remember words can be attached to addresses See Figure 19 S7 Program 1 Edit Insert View Options Window Help s rem amp Symbol Table 1 Symbols S7_coveyortest1 SIMATIC 300 Station CPU312 1
5. before a change of state Transition points are event monitoring points Example sensor inputs States and transitions are alternated in SFC There are three types of variables in the SFC Sequence Function Chart In this program they are represented as Inputs are represented by input bits States are represented by memory bits Outputs are represented by output bits The states is where action are driven output A state may contain one or more outputs The SFC of this program can be seen in the appendix 2 Figure 11 shows an example of an SFC Wait for start State 1 Start is pressed Transition 1 Conveyor run Figure 11 An example of SFC State 2 4 2 3 Flip flop chain The Flip Flop chain is a type of sequence control logic used in program ming The logic principle is that if all the transition state T1 is true the previous state is reset R and the next state is set S There are two main states namely Reset state means to reset the state to value 0 stop running Setstate means to set the state to value 1 start running 21 Programming and testing of storage conveyor in a virtual environment State 1 A UN Move to next step if T1 B A B 1 State 2 State 1 A Move to next step if T1 B A B 1 State 2 Figure 12 Shows how SFC is converted to FBD State 1 A B EJ State 2 Figure 13 Conversion to Flip Flop chain 4 2 4 STEP7 The user program was desig
6. control panel and elevators The proximity sensor in storage level 4 left 13 5 was not working properly All other sensors are working properly The IN OUT conveyor are both functioning properly The elevators are also working properly The control panel buttons are working properly 5 2 Error list Bugs are errors or faults found in systems or software that produces unex pected results and system malfunction The bug found in the system include The model did not open after it had been minimized 5 3 Model improvement This section addresses several improvement recommendations to the mod el The improvement recommendations include Reduction of the control panel buttons to allow a broader view of the model Introduction of a movement direction indicator of the motor Adding a sensor light indicator Adding a storage level movement indicator Adding a reset button that can be used to drive all the actuators to their initial state Adding an emergency stop button Adding a counter value display 30 Programming and testing of storage conveyor in a virtual environment 5 4 Model user s manual User s manuals are written guides in either a paper copy or an electronic document format that provide instructions on how to do or use something They educate users about the product s features and how to use them http www wikihow com Create a User Manual accessed 15 4 2013 5 4 1 Manual usage
7. model In conclusion a demo program was designed improvement recommenda tions were made and a user manual was developed for the model Model input output STEP 7 Radio Frequency Identification RFID 35 p appendices 20 p Programming and testing of storage conveyor in a virtual environment LIST OF ABBREVIATIONS CD Down Counter CPU Central Processing Unit CU Up Counter FB Function Block FC Function FBD Function Block diagram HMI Human Machine Interface I Os Inputs and Outputs IW Input Word LAD Ladder Diagram MPI Multiple Point Interface MRES Memory Reset MW Memory Word OB Organizational Block PC Personal Computer PLC Programmable Logic Controller QW Output Word RF Radio Frequency RFID Radio Frequency Identification S7 SIEMENS STEP 7 SFC Sequence Function Chart STL Statement List VE Virtual Environment VLE Virtual Learning Environment VR Virtual Reality Programming and testing of storage conveyor in a virtual environment CONTENTS D INGRODUCIIOIN S Ecosse eeu ntfi mec ue RR PAREDES RC HS ER RR OR RENS 2 MODEL AND VIRTUAL ENVIRONMENT eese nennen enne PS MANU oro iSt C E P 7 2 2 Simulation iiie eet sid to se abe et oec ae taces rueda id toes eC heeds 7 22 1 Benehtor simulatione s i a erai aeaa dei ede ease suae NR 8 222 Barriers Of simulat of sne a Vadis tutu a LM 9 2 3 arent 9 Zu Virtual Environment iiu cies e COO So He RU des MV D o ARENI
8. the master program block OBI also includes all the function calls OB100 is the complete restart block Function FCs Functions are used to program frequently recurring or complex automation functions They can be parameterized Berger 2005 97 The FCs used in this program are FC1 FC2 FC3 FC4 FCS and FC6 FClin the Box in program FC2is the Box out program FC3 is the Output control program FC4is the Pressured stop program FC5is the Identify colour program and FC6 in the Counter program Implementation of RFID The RFID plate on the in conveyor identifies the box colour by reading the colour code on the box as hexadecimal code displaced as input word IW7 Each colour has a 16 bit hexadecimal code in the memory of the program which is compared with the RFID IW7 input using the compara tor block The comparator compares the two values If the value matches a box colour code the output is copied as a memory bit colour code Blue colour code is 0001u Green colour code is 00024 Orange colour code is 00034 Not identified colour code is 01944 COLOR CODE W 16 0000 Comparator I RFID BOX COLOR TYPE Figure 19 RFID implementation block Counters Up Down counter is used to monitor the state of the model storage levels if its full or empty The storage level can only store two boxes at a time A rising edge at input CU up count counts
9. EP 7 in LAD and FBD Erlangen Publicis Corporate Publishing Berger H 2006 Automating with SIMATIC Erlangen Publicis Corpo rate Publishing Ellafi M A 2003 Simulation in Education Accessed 9 March 2013 http projects edte utwente nl pi sim AliEllafi html Federley S Jussila J Mattila J Horelli J V n nen M 2010 Using simulation models to improve the planning delivery chain Kaunas 5 In ternational Conference on Electrical and Control Technologies Georges L S Viren N N Stanley J H Pamela J M 2005 Barriers to use of simulation based education Accessed 9 March 2013 http www politicalcollectors com Thesis Barriers2620to9620use96200f96 20simulation based 20education pdf Hayford V 2012 Canning Machinery with Siemens Simatic PLC control Programming Test Programming Holyoke M 2011 Accessed 23 Feb 2013 http whatis techtarget com definition 0 sid9_gci866691 00 html http dictionary reference com browse virtual environment accessed 11 April 2013 http www omicron lab com application notes 3105201 1 rfid resonance frequency measurement html accessed 23 March 2013 http www posright com new how RFID work reader functions ac cessed 23 March 2013 http www engineersgarage com insight how rfid tag works accessed 23 March 2013 http www automation siemens com mcms sce en advanced training train ing material download training material
10. NC USON sc defui Mu ror atii RM 32 SOURCES EE 33 Programming and testing of storage conveyor in a virtual environment Appendix 1 MODEL USER S MANUAL Appendix 2 SEQUENCE FUNCTION CHART Appendix 3 PROGRAM STRUCTURE Appendix 4 SYMBOL TABLE Appendix 5 STEP 7 PROGRAM Programming and testing of storage conveyor in a virtual environment 1 INTRODUCTION Recent scientific and technological developments have given rise to ad vancement in computer modeling Computer modeling applications are used in education in the medical field in gaming applications military training aviation astronomy psychology and engineering Simulation technologies are widely employed in the area of training and research Simulations in education are used for both technical and non technical purposes Models are sometime used before an existing system is altered or a new system built to reduce the chances of failure to meet the specifications and to optimize system performance Computer model applications are uti lized in automation system design An example of computer modeling is the energy system optimization model used in modern industries for ener gy optimization and management The Research and Development Centre AutoMaint at HAMK University of Applied Sciences Valkeakoski unit was developing a computer model replica of a storage conveyor in a virtual environment which will be used for teaching PLC programming As a final year student I was given t
11. Programming and testing of storage conveyor in a virtual environment PROGRAMMING AND TESTING OF STORAGE CONVEYOR IN A VIRTUAL ENVIRONMENT HAMK UNIVERSITY OF APPLIED SCIENCES Bachelor s thesis Degree Programme in Automation Engineering Valkeakoski 19 April 2013 Ademola Abdul Rahman Amida Programming and testing of storage conveyor in a virtual environment HAMK ABSTRACT UNIVERSITY OF APPLIED SCIENCES Valkeakoski Degree Programme in Automation Engineering Author Ademola Abdul Rahman Amida Year 2013 Subject of Bachelor s thesis Programming and testing of storage conveyor ABSTRACT Keywords Pages in a virtual environment This thesis was a developmental project to program and test a storage con veyor model developed by the Research and Development Center of HAMK University of Applied Sciences The model will be used to facili tate teaching PLC programming The objective of this thesis was to design a PLC program with SIEMENS STEP 7 for the control of the model and test out its functionality Other objectives included the design of a user s manual for the model improve ment recommendations and identification of bugs in the model The thesis work was divided into three main sections The first section deals with the programming of the model using SIEMENS STEP 7 The second part involves the testing of the model and bug identification The final part describes the design of a user s manual for the
12. S EN Sat 10 25 Mirt al models Sasececdio desees bth canted a ola ems de eam M ema 10 2 6 Pros and Cons Virtual Environment applications eene 10 2 7 Future of Virtual applieatiQns isioose iios en oti te ttes e ated deaveuasatesyievnuaetionss 11 THE MODEL OVERVIEW r enea a nU os pup US Resta 12 3 1 Benehit of this smiodel uu ii diae ei will se i ede iege tenes 12 3 2 Techical descripEOtas ni o edet eI SEE tpe t veta keel erue agar Dese DO eoi 12 SOT OBIOVaLOES associer uude dua ea uuu dba bau ed m EN 13 3 2 27 Strage LEVEN S ic cencorscactas un Moe S DUM MIO Mioidse DG e isse EEN 13 3 2 3 CODIVOOES suot Clo du o rounded Rud at ecu pU SEEE due Dici UM UTR 14 3 4 4 Proximity Sensors be III ERES NEUEN SON eerste ERR V SES nan P eS ER Ee apa 15 3 25 agi als a st a embed ates td 15 3 20 BOX StODDEES Costes datos on eaa thm meet ed 16 3 3 Us r nterface 2 aieo cans are bie denis ea ab e REI UI e epee geen 17 3 31 HMI Control Panel en ced rete n tient 17 Oodd MENUS deutet Nes o Ret eutenun on dat mate te dM ee NI eM 18 9 3 5 Key SHOLICUE So cos ete e arp tdi ac pb mette cud 18 Se Mecca 18 PROGRAMMING WITH SIEMENS DEMO PROGRAM ner 19 4 1 SIEMENS STEP 7 inrait tpe Ue pause iR eese ati erg aede 19 4 20 Model programming procedures eseseesseeeeeeeeeeeee enne enne 19 42 1 Model GDOtatl oT e Dia dedu elon eit tas ee Ae 20 4 2 2 Sequence Function C
13. Simulation p 44 O Leary R Accessed a Feb 2013 http www bioscience heacademy ac uk ftp Resources gc elearn2 pdf Pohjasto H 2010 Automation Lecture series Automation Department HAMK University of Applied Sciences Schwartz T 2012 Which type of model will be most effective in teach ing about moon phases Accessed 23 March 2013 http www slideshare net tschwartz37 physical vs computer models Smith R 1998 Encyclopedia of Computer Science Simulation Article Accessed 23 Feb 2013 http www modelbenders com encyclopedia encyclopedia html Weis S Principles and Applications Accessed 234 March 2013 http www eecs harvard edu cs 1 99r readings rfid article pdf 34 Programming and testing of storage conveyor in a virtual environment Appendix 1 25 Programming and testing of storage conveyor in a virtual environment Appendix 2 SEQUENCE FUNCTION CHART Wait for start Start I 6 0 Stop IN OUT Conveyor Right Elevator 1 Right RFID IW7 Stop Blue box IN OUT Conveyor Right Elevator 1 Right 7sec elapse To Stop Elevator 1 up 12 4 Stop Elevator 1 Right Stopper lvl 2 Up 12 4 Stop Storage lvl 2 Right Elevator 1 Right Stopper lvl 2 5sec elapse T1 Stop Storage lvl 2 Right Stopper lvl 2 Up 16 1 Figure 22 Green box IN OUT Conveyor Right Elevator 1 Right Orange box IN OUT Conveyor Right E
14. The future of virtual applications according to Janet Clarey 2012 can be summarised into the following The future of virtual reality is an augmented reality technology which enhances your perception of reality it is more of a physical real world environment whose element is augmented by a computer generated layer such as sound video and graphics New technology being developed include Human less learning ex ample is surface computing Haptic technology a feeling based tech nology More informal learning technology will emerge in the future Example mobile learning learning with mobile apps More virtual classrooms will replace most conventional classroom to minimize cost in the future 11 Programming and testing of storage conveyor in a virtual environment 3 THE MODEL OVERVIEW The model is a computer replica of a storage conveyor in a virtual envi ronment The model is used to store boxes of different colours into differ ent storage levels and its operation is controlled automatically The model is an example of an automation model which provide pro grammable units actuator to enhance the learning of PLC programming A picture of the model is shown in Figure 1 Green Box IN Blue Box IN Orange Box IN Un ID IN Green Box OUT Blue Box OUT Figure 1 Model Storage conveyor 3 1 Benefit of this model The following are the benefits of this model The model can be programmed like a real storage con
15. a basics step7 programming D ocuments a03 startup pdf accessed 23 March 2013 http www automation siemens com doconweb pdf SINUMERIK SINA MICS 02 2012 E S7P pdf p 1 accessed 234 March 2013 http www systems thinking org modsim modsim htm accessed 23 Feb 2013 http oald8 oxfordlearnersdictionaries com dictionary virtual accessed 23 Feb 2013 http www cs sunysb edu cse529 chap 1 pdf accessed 23 Feb 2013 33 Programming and testing of storage conveyor in a virtual environment http www wikihow com Create a User Manual accessed 15 April 2013 Hunter I W T D Doukoglou S R Lafontaine P G Charette L A Jones M A Sagar G D Mallinson and P J Hunter 1993 A Teleoperated Mi crosurgical Robot and Associated Virtual Environment for Eye Surgery pp 265 280 Janet C 2012 Creating a Learning Environment for the Modern Mobile worker Accessed g h March 2013 http www safaribooksonline com webcast 2012 11 08 190000 safari books online webcast creating learning environment modern mobile Khambekar A What is a simulation model Accessed 23 Feb 2013 http www wisegeek com what is a simulation model htm Maria A 1997 Introduction to modeling and simulation Accessed 23 Feb 2013 http www inf utfsm cl hallende download Simul 2 2002 Introduction to Modeling and Simulation pdf Overstreet C M 1982 Model Specification and Analysis for Discrete Event
16. cessing priority can be speci fied within the framework permitted by the particular CPU Berger 2006 125 The organization blocks OBs and the programming language FBD is used in this program was selected as shown below File PLC z q X Which blocks do you want to add 3 4 Dg Bods BlockName SymboicName V OB1 Cycle Execution OB10 Time of Day Interrupt 0 C OB11 Time of Day Interrupt 1 OB12 Time of Day Interrupt 2 C OB13 Time of Day Interrupt 3 xl 7 Select all Help on OB Language for Selected Blocks C SIL C LAD FBD J Create with source files Preview gt gt 3 ish Cancel H Press F1 tc Lose z omh o oma hp Figure 15 STEP7 block name and language 23 Programming and testing of storage conveyor in a virtual environment The Simatic Manager window gives access to the following functions Project file used to store data and programs Project library Download icon used to download program to the programmable logic controller Online offline button used to switch from online to offline view of the program and vice versa Configure network used to configure PROFIBUS Ethernet and MPI networks Simulation on off PLCSIM used to run and test programs The Simatic Manager window is shown below OBI is the master program block and it appears in the window by default Other blocks FB FC and OBs can be added into the program
17. chnolo gies are being designed to further develop the use of e learning applica tions An example of e learning is the Moodle Modular Object Oriented Dynamic Learning Environment which is a learning management system Programming and testing of storage conveyor in a virtual environment 2 4 Virtual Environment Virtual Environment is a computer generated three dimensional represen tation of a setting in which the user of the technology perceives them selves to be and within which interaction takes place http dictionary reference com browse virtual environment accessed 11 4 2013 A virtual environment is a computer simulated environment Virtual environment applications are widely used in the medical field gaming applications in military training aircraft simulators in astronomy in psychology in education and engineering For example in a medical training application a surgeon can practice par ticular surgical procedures on a virtual patient In addition to visual imag es the surgeon s major form of interaction with the system is by means of specially modified versions of his customary instruments that provide re alistic haptic feedback sensations as the surgeon manipulates virtual body tissues Hunter et al 1993 2 5 Virtual model A virtual model is a model that is made to appear to exist by the use of computer software http oald8 oxfordlearnersdictionaries com dictionary virtual accessed 23 2 2013 Vir
18. cks or files Save and download program to programmable controller After the user program programming tasks are complete download the pro gram to the programmable controller Test and diagnose error test user program by displaying variable values from user program or CPU 28 Programming and testing of storage conveyor in a virtual environment Monitor operation and diagnose hardware This is done by display ing online information about the module A diagnostic buffer or stack contents can be used to determine the cause of the error Archive the program Always remember to keep good documenta tion of your user programs 4 4 Safety requirements STEP 7 program The program should be designed to allow the device to be controlled manually in an emergency situation Implement mechanical or electrical interlocking between automation task to improve safety Emergency stop break switch should be implemented to shut down the operation of the entire device 29 Programming and testing of storage conveyor in a virtual environment 5 MODEL TESTING IMPROVEMENT AND USER MANUAL Model testing involves the testing of the model with the intent of finding faults and errors bugs The different parts of the model and the data ex change between the model and the PLCSIM were tested in this project 5 1 Model part test The model part tested include proximity sensors IN OUT conveyor stor age levels box stoppers
19. en boxes and Level 4 for orange boxes The boxes move in from the left side of the storage level and move out from the right Figure 3 shows the storage levels The blue box is identified by RFID as a 16 bit word 1680001 Green box is identified by RFID as a 16 bit word 1650002 Orange box is identified by RFID as a 16 bit word 1650003 Not identified box is identified by RFID as a 16 bit word 1640194 13 Programming and testing of storage conveyor in a virtual environment MCA eee aiat x ii 3 2 3 Figure 3 Model storage level Conveyors The conveyors are used to move boxes from one place to another in the model The conveyor has belts which are driven by motors The model system has three different types of conveyors In Out convey or Elevator conveyor and Storage level conveyor The In conveyor allows boxes to be added into the system Box in and it can move in both directions The Out conveyor is used to fetch boxes out of the model and it also moves in both directions Elevator conveyor allows the boxes to move onto elevator 1 and move out of elevator 2 Storage level conveyor allows the boxes to be moved from elevator 1 to its storage position and also out of the storage level to elevator 2 Figure 4 shows the conveyors Figure 4 Model conveyor 14 Programming and testing of storage conveyor in a virtual environment 3 2 4 Proximity sensors Proximity sensors are used to detect the
20. ent box colours Figure 9 shows the control panel Stop Start Orange Box IN Green Box IN Blue Box IN Un ID IN Orange Box OUT Green Box OUT Blue Box OUT Un ID OUT Figure9 Model control panel 17 Programming and testing of storage conveyor in a virtual environment 3 3 2 Menus The menus allow the user to perform various functions The menu is di vided into three File contains Reset which can be used to delete all the boxes from the model Quit which is used to exit or quit the model View contains Control was used to open close the HMI control window Log contains warnings and debugs information from the model Help contains Manual which is accessible from the website About Information about the model 3 3 3 Key shortcuts Key shortcut enables the user to use the keyboard to execute some opera tions on the model The key shortcuts include C on the keyboard can be used to open close the control panel win dow T can be used to on off the sensor status indicator Key 1 9 on the keyboard can be used to view the model at a different camera angle Click on the box to camera follow the box in the model 3 4 Safety The safety of both human machine and environment is very important The following are important safety precautions to take before operating the storage conveyor in real life Ensure that the emergency stop button is functioni
21. ers of simulation based education in the medical field for anesthesiologists The study examine this issue with patient simulators The following barriers were discovered Lack of training opportunities Lack of free time Stressful and intimidating environment Fear of educator s judgements Fear of peer s judgements 2 3 Virtual learning A virtual learning environment VLE is a software system designed to support teaching and learning It is a set of teaching and learning tools de signed to enhance the learning experience by including computer and the internet in the learning process Holyoke 2011 An example of a virtual learning environment is the storage conveyor model which can be used to learn PLC programming The model has pro grammable units which can be programmed with any PLC control pro gram The input and output variables can be manipulated to change the control sequence and additional tasks can be implemented These flexible possibilities allow the user of the model to learn and acquire more pro gramming skills Another example of a virtual learning environment in education is the use of web based applications which create a medium for students and teach ers to meet online and exchange ideas such as WebEx which is used for material sharing and web conferencing E learning involves the use of technology and electronic channels in edu cation It is a technologically aided learning and teaching New te
22. hart SEC iei Goin tob oreaitsesad as 21 42 3 EOP Chal ausit ta o EP RE POR OUS ONES tu IM pst deti pde x epu Uds 21 AD A STEP T E 22 420 Program st Ure n A RR Det a OS Iiis aes eu tad d end 24 420 Symbol Editor oae E dap Rom eh Ste ip aea EU E 25 4 2 7 User program creation Implementation of Blocks 25 4 2 8 Download and run PLCSIM program eene 21 4 3 STEP7 programming of a real machine esee 27 4 3 1 Hardware requirement 5 cose cai sortes seda Qe acai oes canseasdaacvcessaes 27 4 3 2 Real machine programming procedures eene 28 4 4 Safety requirements STEP 7 program eese eee entente enne 29 5 MODEL TESTING IMPROVEMENT AND USER MANUAL 30 2 1 Model part festo deron oor de eor care po Er ERS tede Du odaeko copas 30 I 2e o ur gl ee MN P KE 30 Programming and testing of storage conveyor in a virtual environment 5 3 M del improvement siri aoa eoi eR p studios quee sio ieaie i Ode RU KENT 30 DA Model users mand essi bereitet tek eue bosse ed ra NF eta e uev EEA PU ota 31 SET IM anal MIS sos eod terti ven iret ys se ap eu a a EAE eee sccharenazs 31 542 User Te GUN CIC TIES tnt ads oo euh esM E R Pedo aaa aoe 31 5 4 3 Writing the user s manual Jones tenti aeo aer e eee eid ses 31 5 4 4 Access to the User s manual sess css sivssecessocsuctduneand gaseantevesteasgceracboinats 31 o CO
23. he project as a final thesis with the following objectives The first objective was to design a demo program with SIEMENS STEP 7 PLC to automatically control the model in the virtual environment In addition test out the model its features sensors elevators conveyors stoppers and its control panel The testing also includes identification of bugs errors and system malfunction in the model Recommendations feedbacks and improvement suggestions were expected to be given about the model The second objective was to write a user manual about the functionalities key shortcuts controls and operations of the model The user manual is a technical document which gives assistance to students on the usage of the model The project will be used to teach student PLC programming and it is par ticularly effective since students can operate the model from home and at any time Programming and testing of storage conveyor in a virtual environment 2 MODEL AND VIRTUAL ENVIRONMENT 2 1 Model A model is an abstraction of a system intended to replicate some proper ties of that system The model is similar to but simpler than the system it represents Models are used in various scientific and engineering systems Models can be constructed for most systems which may include educa tional systems communication system highway systems research sys tems and imaginary systems Models are generally classified into three according to Tom Schwart
24. l classes Khambekar propose that to create a simulation model three elements are needed Programming and testing of storage conveyor in a virtual environment The parts of the system The interaction between the parts The number and nature of inputs variables Simulations are widely used for educational purposes It is used in training and research particularly when it is expensive or dangerous to allow train ees to use real equipments Example of simulation in education is sim School which is a classroom simulator used by educators to learn class room management techniques An example of simulation in engineering is process simulation which is used in oil refineries to give process parame ters 2 2 1 Benefit of simulation Simulations offer the following general benefit Ellafi 2003 Effective and efficient Simulations help to create familiarity with skills programs systems and process without using the real system or process Cost effective Most simulations are cheaper to build compared to the cost of acquiring the real system Risk free Simulations allow user to test their skills in real life situa tions simulation without real life consequences Flexibility Simulations are easier to modify and manipulate to per form different functions than the real system its imitates Simulations also offer benefits in education for both teachers and students Benefit of simulation for students Simulations are ri
25. lectromagnetic Field Ww Z f RFID Transponder b a Reader jo Reader Coil Transponder Coil Figure6 RFID Radio Frequency Identification OMICRON Lab RFID is used in the model to identify the boxes as they move on the con veyor to determine the level where it will be stored Les 7 shows the RFID Blue box is identified by RFID as a 16 bit word 1650001 Green box is identified by RFID as a 16 bit word 1650002 Orange box is identified by RFID as a 16 bit word 1650003 Not identified box is identified by RFID as a 16 bit word 1620194 Figure 7 Model RFID sensor 3 2 0 Box Stoppers Stopper is located on each storage level of the model towards the end It is used to stop and hold the boxes in place to prevent them from falling from the conveyor Figure 8 shows the box stoppers 16 Programming and testing of storage conveyor in a virtual environment Figure8 Model box stopper 3 3 User Interface The user interface provides a medium where the user can interface or con nect with the model This enables the user to interact operate and control the model The user interface consists of the control panel the menus key shortcuts and mouse behaviour 3 3 1 HMI Control Panel The control panel contains control buttons which allow the user to operate and control the model The control buttons includes the stop and start but tons the box in and box out buttons for the four differ
26. levator 1 Right 7sec elapse T Stop 7sec elapse T4 Stop Elevator 1 up 15 a Elevator 1 up 12 5 Stop T 12 6 Stop Elevator 1 Right Elevator 1 Right Stopper lvl 4 Up Stopper lv13 Up 12 5 Stop 12 6 Stop Storage lvl 3 Storage lvl 4 Right Elevator 1 Right Elevator 1 Right Stopper lvl 3 Up Right Stopper Iv14 Up 5sec elapse T Stop 5sec elapse T Stop Storage lvl 3 Storage lvl 4 Right Stopper lvl3 Up Q2 3 Stop Q23 Stop Elevator 1 Down Elevator 1 Down 16 1 161 Box in Sequence Function Chart 36 Right Stopper lvl 4 Up No ID IN OUT Conveyor Right Elevator 1 Right 12 2 Stop Storage lvl 1 Right Elevator 1 Right 3sec elapse T6 Stop Programming and testing of storage conveyor in a virtual environment Storage lvl 2 Right 132 500msec elapse Tis Elevator 2 up 14 2 Stop Storage lvl 2 Right Elevator 2 Right 3sec elapse T Stop Elevator 2 Down 14 1 Stop Elevator 2 Right IN OUT Conveyor Righk sec elapse T Stop Figure 2 Storage lvl 3 Right I3 4 500msec elapse T Elevator 2 up T1 14 3 Stop Storage lvl 3 Right Elevator 2 Right 3sec elapse T Stop Elevator 2 Down 14 1 Stop Elevator 2 Right IN OUT Conveyor Righk 6sec elapse T Stop Wait for fetch button Storage lvl 4 Righ
27. ned in the Simatic Manager which is an auto mation tool in STEP 7 Simatic Manager Wizard New project was opened by clicking on the Simatic Manager icon on the desktop The CPU contains the central control processor which executes the operat ing systems and the user program assign module parameters and and transmits user data All CPU modules are equipped with an MPI interface for the connection to the programming device operator interface systems or other SIMATIC stations Berger 2006 38 The CPU name was selected on the wizard dialog box as shown below The MPI address has a default value of 2 22 Programming and testing of storage conveyor in a virtual environment KASIMAN STEP 7 Wizard New Project File PLC EE a Which CPU are you using in your project Dc 6ES 312 1AE14 DABO 5ES7 312 5BEO03 DABO 6ES7 312 5ACO2 DABO 5ES7 313 1AD03 0ABO 6ES 313 5BFO3 DABO 6ES 7 313 6CF03 DABO Preview PERDE lt Back i i Finish Cancel Help Figure 14 STEP7 CPU name The organization blocks OBs are the interfaces between operating sys tem and user programs The organization blocks OBs are part of the user program and are called and processed by the operating system when cer tain events occur Berger 2006 125 The organization blocks OBs are divided into priority classes which de termine the sequence of the program processing mutual interrupt ability when several events occur The pro
28. ng correctly Ensure that the mains were disconnected during the service of the ma chine Ensure that personnel are kept away at a reasonable distance to the machine during operation The machine operating program should be designed to allow the de vice to be controlled manually in an emergency situation Implement mechanical or electrical interlocking between automation task to improve safety Ensure that the machine is serviced periodically to improve safety 18 Programming and testing of storage conveyor in a virtual environment 4 PROGRAMMING WITH SIEMENS DEMO PROGRAM 4 SIEMENS STEP 7 STEP 7 is a programming software solution for solving control problems Its automation tool is the Simatic Manager The Simatic Manager is the main tool in STEP 7 Berger 2005 49 The complete program of a central processing unit CPU consists of the operating system and the user program The operating system is a fixed part of the program and cannot be changed but the user program can be changed Berger 200 125 The programming languages in STEP 7 are Ladder LAD Function block FBD and Statement list STL The Demo program user program was designed with FBD language The version of STEP 7 used in this project is V5 5 SPI S7 PLCSIM user interface enables the user to test and run offline pro grams without additional hardware The S7 PLCSIM version used in this project is V5 4 SP5 S7 PLCSIM softwa
29. perly and the bug de tected was reported A user s manual was successfully designed to help the users of the model A major challenge was to understand the objectives and to implement the project Other challenges encountered included The design of the user program sequence The integration of the RFID into the user program The implementation of the counters The model is too complex for inexperience PLC students to understand at once The model should be broken down into smaller units to teaching PLC programming The model can be used for industrial purposes when planning new systems or improving old ones It can also be used in training operators on how to use the system The model project was a laudable one because of the opportunities it will provide for students to learn PLC programming skills It is recommended that more work should be done on the compatibility of the model with the VMware View Client virtual desktop so that students without PLC software on their PC can use the model from home It is also recommended that Industrial Process Models should be con structed to aid the teaching of process measurement and control This model will indicate temperature pressure and flow measurement and con trol It may also include DCS programming This is an important part of automation technology 32 Programming and testing of storage conveyor in a virtual environment SOURCES Berger H 2005 Automating with ST
30. presence of the box and elevators and its information is used in the control program design There are about twenty nine proximity sensors in the model Figure 5 shows the proximity sensors Figure5 Model proximity sensor 3 25 RFID RFID Radio Frequency Identification is a wireless non contact radio fre quency identification technology It is used to track and identify objects at a distance RFID system is an example of automatic identification sys tems Figure 6 shows the components of an RFID gus proposes that an RFID system contains RFID tag or transponder is a small device attached to the physical ob ject which stores and sends data to the reader RFID reader or transceivers receive data from the RFID tag and re spond with some identification information based on its data record RFID application software RFID system basic principle of operation http www posright com new how_RFID_work_reader_functions accessed 23 3 2013 is as follows The RFID reader produces an electromagnetic field When the RFID tag gets into this field it receives the radio frequency RF signal emitted by the reader The RF induces energy into the RFID tag the RFID tag then sends out information stored in the tag chip to the reader The RFID reader receives the signal and sends to the information sys tem centre for processing 15 Programming and testing of storage conveyor in a virtual environment E
31. re is installed separately but in newer version of S7 this separate installation may not be needed The S7 PLCSIM communication is integrated into the Simatic Manager and are both interfaced into the model environment so that the model can be controlled 4 2 Model programming procedures The following procedures were executed in the programming of the model with S7 Design of a program control sequence see appendix Sequence Func tion Chart Design of a program flip flop chain Design of a program structure Creation of a new STEP7 project Define the symbol table Creation of a user program Save and download the program Test and diagnose error 19 Programming and testing of storage conveyor in a virtual environment Design program structure Start STEP7 Create a project Define symbols Create user program Program blocks Call block in program Define local symbols Save program Download program l Test program Diagnose errors Figure 10 STEP7 programming procedures fix program 4 2 1 Model operation The model is a storage conveyor that is used to store boxes in four differ ent storage level based on the colour of the box Each storage level can on ly accommodate two boxes at a particular time Box in Introduce a box with the box button into the in conveyor and press the start button RFID identifies the colour of the box to determine the
32. sk free Students can test simulation systems of real machine without exposure to danger Students can practice different things without fear of damaging any component or unit in the simulation Simulations are an effective way to learn Its create familiarity with systems and processes giving real life experiences Simulations can be paused whereas real machines cannot Pausing al lows more time for students to assess what s going on Benefit of simulation for teachers instructors Simulations are cost effective They require fewer resources to con struct compared to the real equipment Simulation creates a flexible environment for teachers to transfer their learning materials Simulations make teaching easier for teachers since learning resource can easily be distributed to students Most simulations do not pose any safety risk to the students Programming and testing of storage conveyor in a virtual environment 2 2 2 Barriers of simulation Barriers of simulations include Simulation does not run exactly as the real system in a controlled en vironment Most simulations require the user to have access to a PC to use the simulation Poorly designed simulations do not break or damage when wrongly used unlike the real systems Poorly built simulations do not allow full safety precaution to be expe rienced by users A study was carried out at the University of Toronto Canada 2005 to de termine the barri
33. storage level and the in conveyor moves the box to elevator 1 Elevator 1 moves the box to the desired storage level The storage level conveyor move right to allow the box to move into the storage level The box stopper in the storage level keeps the box in place preventing it from falling from the storage level Box out The box can be taken out by pressing the Box out button The box move out through elevator 2 Stop The model can be stopped at any time by pressing the stop button The operation process is automatic See appendix 2 for the model control SFC 20 Programming and testing of storage conveyor in a virtual environment Counters The storage level sensors left and right are used to count the boxes moving in and out of the storage conveyor The sensors are integrated into an up and down counter When the storage level is full no additional box can be added to that level A reset button can be used to reset the counter 4 2 2 Sequence Function Chart SFC An SFC describes the step by step flow of the control process It is also called sequence control which is widely used in automation It is identical to the flow diagram in computer programming The control function is divided into two Namely States or Steps States are where events are driven States can take a long or short time Example the conveyor moves right Transition condition Transition conditions are conditions that must be met true
34. t 13 6 500msec elapse T Elevator 2 up 1 144 Stop Storage lvl 4 Right Elevator 2 Right 3sec elapse T Stop Elevator 2 Down 14 1 Stop Elevator 2 Right IN OUT Conveyor Right 6sec elapse T Stop Box out Sequential Function Chart 37 165 Storage lvl 1 Right 13 0 500msec elapse T Storage lvl 1 Right Elevator 2 Right 3sec elapse T Stop Storage lvl 1 Right IN OUT Conveyor Righk sec elapse T Stop Programming and testing of storage conveyor in a virtual environment Appendix 3 PROGRAM STRUCTURE 38 Programming and testing of storage conveyor in a virtual environment Appendix 4 SYMBOL TABLE 39 Programming and testing of storage conveyor in a virtual environment Appendix 5 STEP 7 PROGRAMS 40
35. the box going into the model and input CD down count counts the box going out of the conveyor The counter output value is a 16 bit memory word MW which is copied into a comparator The output value is compared with zero and two a item ized below Ifthe value is zero then the storage level is empty If output value is two the storage level is full If the output value is one the storage level can only accept one more box 26 Programming and testing of storage conveyor in a virtual environment A reset button can be used to reset the counter to default state The output word QW is used to display the value of the counter The value of the counters is then shown in the counter value indicator on the control panel 4 2 8 Download and run PLCSIM program After all configurations were completed in the user program the program was downloaded to the CPU The PLCSIM provide an offline simulation resource A program commu nication channel is established between the S7 programs the PLCSIM and the model This allows the user program to be tested and errors can be de tected Data is continuously exchanged between the PLCSIM and the model as the program output affects the model actuators The figure below shows the data flow fioul Input Output communicabon STEP7 PLCSIM MODEL Read data Inputs Z Outputs Write data Figure 20 Data flow diagram 4 3 STEP7 programming of a real machine
36. tual models are easier to study and manipulate because of their flexible nature Virtual model validation techniques include simulating the model under known input conditions and comparing model output with system output Maria 1997 Examples of virtual technologies are virtual library virtual storage virtual classes and virtual machines 2 6 Pros and Cons Virtual Environment applications Pros of virtual environment according to Ros O Leary 2013 include It widens student access on and off campus to learning resources Itis flexible and easy to manipulate t can be used to create a simulated environment which gives a lifelike experience Its minimize cost in training and research since a virtual environment can be built with low cost considering the material cost of building the actual machine It provides an enabling environment for materials and information to be shared Itis not difficult to use compared to the complex real machine It enables user to control their own learning 10 Programming and testing of storage conveyor in a virtual environment Cons of virtual environment include Off campus access to hardware and networks can be problematic for students It is not a real machine so the user does not get the actual feeling of using a real machine Most virtual environments can only run on a PC therefore cannot be used by a user without a PC 2 7 Future of Virtual applications
37. veyor enabling the user to learn PLC programming The model can be used without any fear of damaging any machine component The model is easily accessible to the user once the zip file has been in stalled The model is cheaper to install than installing real storage conveyor The model does not pose any safety risk to an inexperienced user 3 2 Technical description The model consists of eight belt conveyors four storage levels two eleva tors four stoppers twenty nine proximity sensors RFID control panel buttons and motors It also contains the inputs and the output I O unit which receives and send data in and out of the model Most input has a Boolean data type The in 12 Programming and testing of storage conveyor in a virtual environment EE Eris iu 2i a put and output are stated in the program symbol table that will be dis cussed later in this report 3 2 1 Elevators The elevators move the boxes between levels from the first level The ele vators are affected by the program outputs which drives the elevators up or down There are two elevators in the model Elevator 1 and Elevator 2 El evator 1 takes the boxes in and elevator 2 takes the boxes out fetch box Figure 2 shows the elevators Figure2 Model elevator 3 2 2 Storage levels There are four storage levels and each level store a specific box colour Level 1 is for not identified boxes Level 2 for blue boxes Level 3 for gre
38. z 2012 2 Namely Conceptual models are simplified representations describing physi cal or social systems to enhance understanding of such systems Ex amples are the Big Bang theory eletrons orbiting the nucleus of an at om Physical models are physical copy or representation of a system or object that can be held Examples are the human body model the globe Computer models are computer generated representation of a system to simulate its behaviour Examples are mathematical model weather forecast model the storage conveyor model Other examples of models are crowd control model paper making model and factory process model Models are widely used in automation engineering to represent different automation systems machines which can be used in teaching training and research The storage conveyor model is an example of an automation model used to learn PLC programming Another example is the Automat ed Highway System model used in traffic control and management 2 2 Simulation Simulations are used to mimic the operations of a physical or abstract sys tem using a computer software A simulation is a computerized model of a system which allow the system to be studied and experimented with Ellafi 2003 stated that simulation models have three major functions Recreational example is gaming simulations Decision making Problem solving example mathematical simulations Instructional example virtua
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