PLC BASED BREAKDOWN NOTIFICATION MANAGEMENT SYSTEM BY SAP

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1 PLC BASED BREAKDOWN NOTIFICATION MANAGEMENT SYSTEM BY SAP Nalina H D 1, Spoorthi Y 2 1 Assistant Professor, Dept of ECE, GSSSIETW, Mysuru (India) 2 Assistant Professor, Dept of ECE, GSSSIETW, Mysuru (India) ABSTRACT Maintenance of complex industrial system consisting of multiple assets has started receiving more attention in academic literature over the past decade. The event of malfunctioning of the machine which seriously endangers the further production, results in the reduced opportunity time of the machine. Such exceptional or malfunctioning situations require a quick response from the maintenance department. In order to overcome this drawback, a PLC based breakdown notification management system is designed which converts all the process that were involved in conveying the machine breakdown notification to the maintenance department into an automatic process. In this system, the breakdown notification is sent to each person in the respective maintenance department, thereby reducing the communication time from an average of 45 minutes to 1 minute which in turn enables the quick restoration of production and thus contributes to the efficiency, customer service, high quality, safety, on-time delivery and customer satisfaction. Key Terms Computer numerical control machine (CNC),Programmable logic controller(plc), Extensible Markup Language (XML). I. INTRODUCTION Plant maintenance refers to the methods, strategies and practices used to keep a manufacturing industry running efficiently. The main purpose of the plant maintenance is to maintain and maximize the performance of production equipment efficiently and regularly. A maintenance plan can include scheduling time for equipment checkups, troubleshooting and general cleanup etc. Through short daily inspections, cleaning, lubricating and making minor adjustments, minor problems can be detected and corrected before they become major problem that can shutdown a production line. It prevents the breakdown or failures and minimizes the production loss from failures. This also increases the reliability. The different types of maintenance are Breakdown maintenance, Scheduled maintenance and planned maintenance. Breakdown maintenance implies that repairs are made after the equipment is failed and cannot perform its normal function. The improperly performed maintenance can cause problems because of faulty parts, maintenance error or decreased profits. Lack of maintenance can lead to dangerous situations and accidents. 40 P a g e

2 Since the event of breakdown of the machine is unpredictable, there might be an excessive delay in the production process which in turn reduces the opportunity time of the machine. Hence, a proper maintenance is needed to keep the machines and working environment safe and reliable. [5] The Computer Numerical Control machine (CNC) tool is a kind of typical complex system with complicated structure and failure styles in which the failure rate of one component is not only influenced by its internal failure, but also by interactive failures of other components. As an every electromechanical industry aims at providing an uninterrupted service in their production, these failures have to be recovered quickly. The present methodology being used for the maintenance is completely a manual process. Figure 1.1 Manual process of sending notification. Whenever the CNC machine results in the breakdown, all the process that is involved in sending the breakdown notification from the operator to the supervisor and then to the respective maintenance department is completely a manual process, which in turn results in the communication delay of 45 min and is as shown in the figure1.1, as a result of which the opportunity time of the machine reduces. In this system, the maintenance department may or may not come across the breakdown notification because the message from the superior is sent only to one person in the maintenance department. This increases the response and recovery time of the machine. In order to tackle the problems present in the existing system, a PLC based breakdown notification management system by SAP is designed with an aim of converting all the process that were involved in sending the message into an automatic process. This system reduces the communication delay from 45 min to 1 min which is depicted in the figure1.2. Figure 1.2 Automatic process of sending notification 41 P a g e

3 Machine can be brought back to its normal state as quickly as possible because the notification is sent to each person in the maintenance department through . Thus helps in reducing the response and recovery time of the machine thereby increasing its opportunity time. II. DESIGN METHODOLOGY The design methodology proposed in order to overcome the drawbacks of the existing system is as shown in the figure2.1. Figure 2.1 Proposed Systems Whenever there is a failure in the CNC machine, the notification has to be sent to SAP software so that it can send the breakdown notification to the respective maintenance department. Since, the CNC machine cannot directly communicate with the SAP software, an intermediate hardware called Programmable Logic Controller (PLC) is used in the present methodology. When the CNC machine results in the breakdown, an error signal is given to PLC. The PLC is programmed using a language called Ladder Logic. The function of the PLC is to identify the particular type of error by the information obtained from CNC machine. Since PLC is hardware and SAP is software, a common platform has to be established so that they can communicate with each other and that platform is provided by the Extensible Markup Language (XML) through a communication protocol called OPC which is similar to that of TCP/IP protocol which provides a path for the flow of information. XML is a markup language that defines a set of rules for encoding a document in a format which is both human and machine readable and it enables to write the own tags as per the requirement rather than a general requirement. The advantage of using this is both PLC and SAP can understand XML language. Here the scripts are predefined. So whenever the PLC sends a particular type of error, the scripts related to that error will be pushed and dumped on to the SAP.System Application and Products (SAP) in data processing is software that relates to Enterprise Resource Planning (ERP). The SAP has a database of all the information related to CNC machine including the type of error, the day, date and time at which the error had occurred etc... sends the notification to the respective maintenance departments through by GSM server. The notification is sent in such a way that the breakdown information should reach to each and every person in the maintenance department as a result of which a quick response is obtained. 2.1 Hardware Description System design consists of the following components 1. Rexroth PLC - It is used as it provides a scalable hardware platform and standardized communication interfaces and it is used to differentiate between the different types of error e.g. mechanical, electrical etc. in this system. 2. Power Cord - is used to connect PLC to the mains electricity supply via extension cord. 3. RJ45 Ethernet Cable - is used to connect computer to Ethernet switch. 42 P a g e

4 2.2 Software Description 1. IndraWorks Engineering - is used for ladder logic programming. These provide access to all the system components and also enable the open system support of standardized interfaces. 2. VI-Composer - this is a powerful tool used for the visualization and parameterization of the equipment related data of the IndraControl VCP02 for the lower end-hmi. 3. WinStudio - It is mainly used for the visualization and parameterization for the higher end-hmi. With the WinStudio, individual application can be created quickly, easily and efficiently. 4. Visual Script language (VB) - is used to transfer the files from source to destination and to implement logics and algorithms within the WinStudio software. 5. XML language - It sends the encoded documents consisting of breakdown details to the SAP. III. IMPLEMENTATION A CNC machine is an integration of various modules like electrical, mechanical, instrumental etc. Since this is a complex system, the failure rate of an individual component is subsequently high. In this paper, four types of errors from the CNC machine are considered that is electrical, mechanical, instrumental and miscellaneous error. The corresponding electrical circuit is as shown in the figure3. Figure3. Electrical circuit diagram The errors from the CNC machine are given to the input ports of the PLC which are represented by Ix0.0, Ix0.1, Ix0.2 and Ix0.3 respectively. The PLC operates on 24V DC supply. When an electrical error occurs in the CNC machine, the corresponding input switch S1 will be in closed condition as a result of which the lamp L1 connected to the output port Qx0.0 glows and similarly for other errors. The data related to the breakdown of machine is categorized based on the parameters and communicated with the further blocks through an Ethernet port. 3.1 Interfacing of PLC and PC Hardware interfacing is as shown in the figure P a g e

5 Figure3.1. Interfacing of PC and PLC The physical interfacing between PLC and PC is done using RJ45 cable and the communication is established by pinging the IP address of both. 3.2 Programming PLC Ladder logic or Ladder diagrams is the most common programming language used to program a PLC and the software which is used for this purpose is Indra Works Engineering that support the real time communication and provides access to all the system components. The Ladder logic programming written for the corresponding electrical circuit is as shown in the figure 3.2 below. Figure 3.2 Ladder logic programming The normally open switch corresponding to the electrical error from PLC is dragged and dropped into the rungs from the tool bar menu and it is named as %Ix0.0. Similarly the load is named as %Qx0.0. The same procedure is followed for other types of error. Once the logic is written, it has to be simulated which is done by logging into simulation mode. Then the run button is selected which runs through each and every rung and shows the syntax error. After having the successful simulation, the logic containing particular breakdown information has to be linked to the visualization software through OPC driver and server configuration.[1][2] 3.3 OPC Configuration Object Linking and Embedding (OLE) for Process Control (OPC) enables the exchange of data between control application and multivendor devices and can communicate continuously among the PLCs, HMI stations, software applications on desktop PCs. The variables defined in an OPC driver configuration allows to 44 P a g e

6 communicate data with the connected PLC. Each variable used in the driver body must have been previously defined in the Database-Manager which is as shown in the figure 3.3. Figure3.3 OPC driver configuration The tag field indicates the variable names into which the data from the PLC has to be stored, the item field indicates the variable name for which the current value of PLC has to be stored and the scan field has the variable name always which indicates that the variable content is updated regularly. 3.4 VI-Composer VI-Composer is visualization software that provides the pre-designed templates and extensive libraries in the development environment to facilitate the implementation of particular application. In order to enable the VI- Composer, VCP02 is selected from the visualization. [4] Figure 3.4 Creation of Screen A new screen is created which is as shown in the figure 3.4 by the information obtained from the OPC driver where in the input1, input2, input3 and input4 represents electrical, mechanical, instrumental and miscellaneous errors respectively and it also indicates only the status according to PLC s inputs. 3.5 WinStudio It is the powerful visualization software for the embedded terminals and PC-based HMI s. The visualization screen is as shown in the figure 3.5(a). 45 P a g e

7 Figure 3.5(a) Creation of screen Using the toggle color function as the object property, the desired color of the object is selected by entering the value of variable as 0 for red color and 1 for green color and flashing speed of the object is given as 1000ns. Figure 3.5(b) Simulation The above figure 3.5(b) indicates the status of PLC, where in all the blocks are in red color as the value of the variable in the change limit is 0. This indicates that there is no change in the position of the switch which in turn specifies that no breakdown has occurred. The visual script language (VB script) is a simple, standard and flexible scripting language that enables to establish a common platform between the hardware and software modules and is executed only on the visualization screen ON condition and it then checks for each and every input. If any of the input is in the ON condition, the XML scripts regarding the breakdown information is copied from the source and sent to the destination i.e. to the SAP software. The XML scripts are as shown in the figure 3.5(c). <Header> <Body> <MaintenanceRequest> <IndividualMaterialIDschemeID= >100007</IndividualMaterialID> <MaintenanceWorkCenterID= >IEF200</MaintenanceWorkCenterID> <ReportedDateTime> T17:17:00</ReportedDateTime> <RequestedProcessingPeriod> <startdatetime> t17:17:00</startdatetime> <EndDateTime> T17:17:00</EnddateTime> </RequestedProcessing Period> <MachineryBreakdownIndicator>True</MachineryBreakdownIndicator> <MachineryMalfunctionPeriod> <StartDateTime> T17:17:00</StartDateTime> </Machinery/MalfunctionPeriod> </MaintenanceRequest> </Body> Figure 3.5(c) XML scripts 46 P a g e

8 3.6 Source Folder The source folder is as shown in the figure 3.6(a). Source folder is like a database for all the parts operating in CNC machine. As we know that various errors occurs in CNC machine, considering electrical, mechanical, instrumental errors and miscellaneous there are four folders named input1, input2, input3, input4 respectively. Input1 consists of xml scripts which in turn hold the complete information about the electrical part. Similarly the other folders operate. Figure 3.6(a) Source Folder When we double click the input folder we can see the.xml files in it. This is as shown in the figure 3.6(b). When we write the VB codes to transfer the file from source folder to target folder, we specify the address of the xml file in the source path. For the file to appear in target folder, the target path is given with a URL of the server. The xml file is transferred to the destination along with the date and time at which the error has occurred. Figure 3.6(b) XML files within folder IV. RESULTS AND DISCUSSION This system ensures that the breakdown notification is conveyed to maintenance department very quickly. Since all the processes are automated, the communication time is reduced to 1minute from 45 minutes. This can be clearly explained by the following graph in figure P a g e

9 Figure 4 Graphical representation of communication time in both manual and automated process. V. CONCLUSION AND FUTURESCOPE This paper proposes an efficient system in coveying the breakdown notification from the plant to maintenance. The way which is encorporated in coveying is through sending an to each and every person in the maintenance. There are many more methods like calling and sending a message or even capturing the picture of the breakdown and sending it instead of an . This can come into operation in future time. REFERANCES [1]. PLC Programming with Rexroth IndraLogic 1.0 Operating and Maintenance Guide. [2]. Rexroth IndraControl L10, Project Plannin Module [3]. VB Script tutorial [4]. Training manual VI Composer Revision 04 / 2005 [5]. An Introduction to total productive maintenance by Venkatesh J [6] [7] [8] 48 P a g e