Abstract:
A solution is disclosed for an overall equipment effectiveness (OEE) analysis for a manufacturing execution system (MES) allowing a comparative analysis that makes it possible to build links and relations among the values found in a report with raw data acquired from the field. The solution is a web application running on a web server and on OEE databrowsers running on clients. In order to come to a comparative analysis an OEE-server is provided with the functionality to acquire data from the MES of the production plant, to perform scheduling for reports, and to perform run time query executions. Additionally the web server gets data from a data mining support database.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority, under 35 U.S.C. §119, of European application EP 11 196 060, filed Dec. 29, 2011; the prior application is herewith incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a method and a web application for overall equipment effectiveness (OEE) analysis according to the independent claims. 
         [0004]    In the context of this invention reference is made to manufacturing execution systems which comply with the ISA S95 standard as referenced herewith [2], [3] and [4]. 
         [0005]    Overall equipment effectiveness (OEE) is a hierarchy of metrics which evaluates and indicates how effectively a manufacturing operation is utilized. The results are stated in a generic form which allows comparison between manufacturing units in differing industries. It is not however an absolute measure and is best used to identify scope for process performance improvement, and how to get the improvement. If for example the cycle time is reduced, the OEE can also reduce, even though more products are produced for less resource. Another example is if one enterprise serves a high volume, low variety market, and another enterprise serves a low volume, high variety market. More changeovers (set-ups) will lower the OEE in comparison, but if the product is sold at a premium, there could be more margins with a lower OEE. 
         [0006]    SIMATIC IT OEE/DTM—a product of Siemens AG—provides dedicated functionality and a GUI for equipment efficiency analysis and root-cause analyses, such as data acquisition and aggregation into OEE key performance indicators (KPIs), as e.g. availability, performance, quality, OEE and many others, including custom KPIs. 
         [0007]    In published, European patent application EP 2 339 418 A1 [1] a method for improving the efficiency of a production are disclosed via a model and a simulation. The method is based on the steps of: modeling a production facility into a virtual production facility; simulating at least one working of the production facility from a virtual working of the virtual production facility; collecting at least one data related to the virtual working; and computing at least one overall equipment effectiveness key performance indicator from the data. 
         [0008]    Up to now, using the SIMATIC overall equipment effectiveness product option, the analysis of data coming from the field has been delegated to different tools that can be grouped as now described. 
         [0009]    Reporting Tools: 
         [0010]    They allow the analysis on a large time span. Reports highlight the main production indexes on pre-processed data and they are useful especially for the analysis of the production &lt;&lt;already done&gt;&gt;. Reports are based on scheduled calculation periodically updated in a background process. As they are calculated, they can be viewed in charts and tables. 
         [0011]    Runtime Tools: 
         [0012]    They give the possibility of querying the database and they let the user insert the parameters of the query e.g. the time range and the selection of the equipment. 
         [0013]    Border Line Tools: 
         [0014]    Operators on the line of production have a set of standalone and web applications that display in charts all the main data coming from field. Using these tools, operators can modify and fix some input data such as the identifier of the order of the production and they can detail the cause of a stop. These tools give information e.g. about the count of pieces produced during the actual shift and the state of the pieces of the equipment of the line. 
         [0015]    The main differences between the report and the border-line tool are that the first one is useful for long term analysis while the second one is related to the &lt;&lt;on-going&gt;&gt; production. The runtime tools can be used in order to close this gap. Although the input data are always the same, the details of analysis allowed are different. 
         [0016]    In the case of reports, the analysis is a &lt;&lt;top-down&gt;&gt; analysis: it means that the user refines the time range of the calculation (e.g.) from one year to one month and then to one hour (depending on the configuration). The limit of this kind of analysis is that it depends on the configuration of the scheduled calculation. 
         [0017]    In the case of runtime tools, it is possible to extract data setting the parameters of the query. This kind of analysis is not integrated with reports and border line tools. 
         [0018]    In the last case, the border line tools allow the &lt;&lt;bottom-up&gt;&gt; analysis from raw to aggregated data: the main constraint is the time range used during the production (e.g. the current worked shift). 
         [0019]    There is no tool allowing a comparative analysis that makes it possible to build links and relations among the values found in a report with raw data acquired from the field. Due to the comparative analysis, it could be possible to extract a list of causes that can affect the production and a list of rules (let&#39;s say &lt;&lt;patterns&gt;&gt;) that can help the management to improve the production. Using this tool, it could be possible to answer the following questions: 
         [0000]    i) When the production is lower than expected, what is the bottleneck machine of the line? And what is the main cause of failures?
 
ii) How many times during the week was the production over the target?
 
         [0020]    Up to now, it is not possible to have a comparative analysis moving from one tool to another. 
       SUMMARY OF THE INVENTION 
       [0021]    It is therefore an objective of the present invention to provide a solution for an overall equipment effectiveness analysis for a manufacturing execution system allowing a comparative analysis that makes it possible to build links and relations among the values found in a report with raw data acquired from the field. Due to the comparative analysis, the solution allows in particular forecasting an effect of a correction of a production facility parameter on the production facility efficiency within the manufacturing execution system. 
         [0022]    The objective is reached by a method and a web application with the features given in the independent claims. 
         [0023]    The invention according to the independent claims has the following advantages: 
         [0000]    1. Only on a client side all the main features of reporting, runtime and border line tools have to be integrated: users can complete their analysis without switching from one tool to another.
 
2. The distributed architecture shares the computational load among database server, OEE server and web server. Clients must only render the results and let the user select them.
 
3. The data mining service moves from the archived data for reporting tools to runtime execution of queries depending on the client requests. This service is based on data mining algorithms written on top of OEE database: starting from the configuration of a report or a runtime query, they are able to add a list of useful constraints for building a new query.
 
4. A comparative analysis is possible: up to date reports are static and user can compare results moving from one report to another.
 
5. Pre-calculated results are used which allow reducing the data on the network between all the computers involved. When the system switches to runtime queries, the set of data has been restricted.
 
         [0024]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0025]    Although the invention is illustrated and described herein as embodied in a method and web application for overall equipment effectiveness analysis, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0026]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0027]      FIG. 1  is an illustration showing architecture of an OEE databrowser application; 
           [0028]      FIG. 2  is a bar chart depicting result of filters in the last 6 months; 
           [0029]      FIG. 3  is a bar chart grouping the result of  FIG. 2  by equipment; 
           [0030]      FIG. 4  is a bar chart showing filtering of the results for a specific period for a cause; and 
           [0031]      FIG. 5  is a bar chart grouping the results of  FIG. 4  by showing particular causes. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    In order to have a concise wording, some definitions are given in the following paragraphs. 
         [0033]    A &lt;&lt;web application&gt;&gt; is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is coded in a browser-supported language (such as JavaScript, combined with a browser-rendered markup language like HTML) and reliant on a common web browser to render the application executable. Sometimes the terms OEE databrowser application and OEE databrowser are not distinguished consequently, but from the context there is no ambiguity for that reason. 
         [0034]      FIG. 1  depicts both the software and the hardware architectures of a web application. The web application is in context with this invention called an &lt;&lt;OEE DataBrowser application&gt;&gt; on the server side of the OEE databrowser. The term &lt;&lt;OEE DataBrowser&gt;&gt; is used for a browser  41 ,  42 ,  43  on the client side  4 . 
         [0035]    Referring to  FIG. 1  the database server  1  is a machine dedicated to the storage of data and to ensure that the OEE database  11  is running always. The database server  1  hosts the OEE database  11  and a data mining support database  12 . 
         [0036]    The data mining support database  12  contains data for the OEE analysis and is used only by the OEE databrowsers, wherein an OEE databrowser has the meaning of browsers  41 ,  42 ,  43  running on a client  4 . 
         [0037]    On a workstation, called an &lt;&lt;OEE Server&gt;&gt;  2  three services are ensured: 
         [0038]    the acquisition of data  21  from the field, 
         [0039]    the scheduling of calculations  22  for reports and the, and 
         [0040]    execution  23  of runtime queries for runtime tools. 
         [0041]    Scheduling of calculations  22  includes: Due to the fact that reports displays complex results coming from different calculations on a huge number of records (it may reach millions of records), for performance reasons, it is important to run the calculation one time—one time in the sense of once—for all reports and store its results in the OEE database  11 . Then, following a scheduling strategy, these results are updated, e.g. once within one hour. 
         [0042]    The web server  3  executes the web application of OEE databrowser and hosts the &lt;&lt;data mining service&gt;&gt;  31 . The latter contains in general the process of discovering new patterns from large data sets. The goal of data mining is to extract knowledge from a data set in a human-understandable structure. In context with the invention this data mining service has the tasks: 
         [0043]    getting data from scheduled calculations; 
         [0044]    getting data from runtime queries; 
         [0045]    proposing a set of pre-built queries based on the configuration of the scheduled calculations and on the user selection coming from client  4  applications such as the OEE databrowser  41 ,  42 ,  43 ; 
         [0046]    proposing new queries based on results of scheduled calculations, runtime queries, user selection and metadata tags of previous analysis; 
         [0047]    storing the new queries and results as patterns using metadata so that they can be repeated, modified and reapplied to a new set of data. These metadata linked to data coming from reports and runtime queries are stored in the data mining support database; 
         [0048]    executing data mining algorithms in order to find the results as soon as possible. 
         [0049]    On all clients  4  is the OEE databrowser  41 ,  42 ,  43  running with a the graphic user interface allowing to access the data mining service  31  running on the web server  3 . 
         [0050]    The web server  3  side of the OEE databrowser application is implemented as a Microsoft ASP.NET solution containing both web services and ASP.NET pages. ASP.NET is a web application framework developed and marketed by Microsoft to allow programmers to build dynamic websites, web applications and web services. ASP.NET is built on the Common Language Runtime CLR, allowing programmers to write ASP.NET code using any supported .NET language. The web services give an entry point for the requests of data coming from the OEE databrowsers  41 ,  42 ,  43  on the clients  4  that can be implemented as a Rich Internet Application in Silverlight  4  or in any other languages supporting web services preferably as WPF. The windows presentation foundation (WPF) is a computer-software graphical subsystem (developed by Microsoft) for rendering user interfaces in windows-based applications. 
         [0051]    The OEE databrowser  41 ,  42 ,  43  mirrors the server side functionality using interactive charts/reports and with the below described features. 
         [0052]    1. it allows to filter the preconfigured set of queries for reports using the following data:
       the selected equipment of pieces of equipment;   the time range;   the name of calculation executed in the report;   conditional statements built with wizards (e.g. the minimum OEE during the production of a specific product);       
 
         [0057]    2. it allows to switch from reports to runtime calculations and vice versa without the user noticing; 
         [0058]    3. it allows to integrate results of report with runtime calculations; 
         [0059]    4. it allows to show the results of the defined filters in charts and tables; 
         [0060]    5. it allows storing the results and the filters defined in the data mining support database  12  so that they can be reopened for new analysis later. 
         [0061]    The OEE databrowser application requires a dedicated analysis of OEE in order to write data mining algorithms. They are a set of rules based on the mathematical model of OEE and they highlight a decision tree that guides the users during the analysis. 
         [0062]    The OEE databrowser  41 ,  42 ,  43  on the client side  4  is the main graphic user interface GUI of the data mining service  31  and data mining support database  12 . The main functionality of the data mining service  31  is to allow the execution of data mining algorithms on runtime data through a cyclic process. The steps defined above for the OEE databrowser application can be repeated in order to, to update and/or increase the data mining support database  12 . 
         [0063]    Up to now, in SIMATIC IT, the integration among reports, border line and runtime tools are left to the end users that can switch among the tools depending on their analysis. The integrated solution proposed in the present invention disclosure increases the functionalities of the product: first of all, it allows moving from macro-analysis to micro-analysis pointing out details required by the end users. Moreover, storing the analysis in the data mining support data base  12 , it is possible to repeat and reapply the analysis to new set of data. In this way, it is possible to increase the database of the data mining with new results coming from data mining algorithms on data acquired from field. 
         [0064]    As an example, let&#39;s investigate the main cause of stops in the last 6 months on a line of production. When the stop is greater than 20 minutes, what is the main cause? Is it possible due to a miss of raw materials or to a failure on specific equipment? 
         [0065]    The OEE databrowser  41 ,  42 ,  43  on a client  4  shows the list of calculations preconfigured and the list of pieces of equipments. The user can select the line and the time range of the analysis. Then, due to the fact that it was defined a report for the state duration calculus showing how long an equipment was in a state, he can select it and filter on the state name &lt;&lt;stop&gt;&gt;. A bar chart depicts the result of the filters in the last 6 months ( FIG. 2 ) but there is no difference between one piece of equipment of the line and the others. In order to see a difference, the user must group the result by equipment and the result is depicted in  FIG. 3 . State duration means how long equipment is/was in running status or stop status. 
         [0066]    Let&#39;s assume a user wants only the result of the equipment where the duration of stop is longer than 5 minutes, a conditional statement must be applied to the result: In this case the OEE databrowser shows a wizard helping the user in the filtering of the result. The result of the filtering is depicted in  FIG. 4 . 
         [0067]    Therefore users on the border line must justify the stops of equipment settings. For showing the causes of stop, the user can enter the detail requirement of the cause to the chart.  FIG. 5  shows a detailed view of the main causes of stops. 
       LIST OF REFERENCE SIGNS, GLOSSARY 
       [0000]    
       
           1  Database server 
           11  OEE Database 
           12  Data Mining Support Database 
           2  OEE Server 
           21  Acquisition of data 
           22  Scheduling for reports 
           23  Runtime query execution 
           3  Web Server 
           31  Data Mining Service 
           32  Web application running in IIS 
           4  Client, clients 
           41 ,  42 ,  43  Browser, OEE Databrowser 
           5  Production Plant with MES 
         DTM DownTime Monitoring 
         IIS Internet Information Service 
         KPI key performance indicator 
         MES manufacturing execution system 
         OEE Overall Equipment Effectiveness 
         SIMATIC IT manufacturing execution system MES, a sophisticated, highly scalable 
         MES that conforms to the ISA S95 standard 
       
     
       LIST OF CITED DOCUMENTS 
       [0000]    
       
         [1] EP 2 339 418 A1 &lt;&lt;Method and device for enhancing production facility performances&gt;&gt; Siemens Aktiengesellschaft, 80333—München 
         [2] ANSI/ISA-95.00.01-2000 Enterprise-Control System Integration Part 1: Models and Terminology 
         [3] IEC 62264-1 Enterprise-control system integration—Part 1: Models and terminology 
         [4] IEC 62264-2 Enterprise-control system integration—Part 2: Object model attributes