The 10th INTERNATIONAL DAAAM SYMPOSIUM
Vienna University of Technology, Vienna, Austria
21-23rd October 1999

NEW SOFTWARE- AND NETWORKING-CONCEPTS BRING MORE FLEXIBILITY TO SHOPFLOOR-DATA ACQUISITION SYSTEMS

Baumann, C. & Kittl, B.

Abstract: The use of up-to-date software- and networking-technologies on the shopfloor-level (Multi-Tier, COM, DCOM, Corba, Java) provides new methods for implementing production- and machine-data acquisition systems, which can redefine the term "flexibility".

Key words: Shopfloor-data, Intranet, Multi-Tier, DCOM, Corba.

1. INTRODUCTION

To start with it is helpful to examine how the term "new technologies" will be applied in the following article. "New technologies" are being used for several years to a wide extent on the companies "office-levels". Contrary to this development, the implementation of innovations regarding information-technology into the shopfloor-level happened in a more conservative way, because of obvious reasons. In this sector new technologies are only implemented after having given proof of not only representing a new trend in technology fashion but rather having chief characteristics like being reliable, robust etc.. Therefore "new" in this article refers to the context of "shopfloor-level".

2. "NEW TECHNOLOGIES"

"New technologies" include especially the following sectors of information technology: hardware, operating systems, user interfaces, networking, communication- and software- architecture.

In the domain of hardware and operating systems the "Wintel-alliance" (Microsoft Windows on Intel-platforms) began to establish itself also on shopfloor-level. I.e. PCs based on Intel-processors, either complete, powerful workstations or just "embedded systems" with Microsoft's operation system Windows (usually NT, but also the special version "Embedded NT or the light version "Windows-CE" is used). Of course this implies graphical user interfaces and mouse-operation on the shopfloor-level, which carries all its advantages and drawbacks.

Regarding the sector of networking it has been realised that the benefits of the combination Ethernet and TCP/IP (availability, independence of manufacturers, flexibility of the architecture, transmission rate, costs etc.) are much more important than its minor technological limitations (e.g. the non-determinism of CSMA/CD). Therefore Intranets can be used in nearly all areas of the shopfloor level with some exceptions: typical settings for field- and sensor/actor-bus systems are and will keep being excluded.

The technologies for communication are usually based on TCP/IP. Apart from the "classical" sockets-model the "component-object-model" (COM) in its version DCOM ("distributed COM" [1]) is applied extensively. Nevertheless its drawbacks have to be recognised: It can be used only efficiently in LANs (DCOM cannot be routed directly, it must be tunnelled into HTTP, which is not very efficient) and the configuration is quite complex. However also the DCOM based "OLE for process control" (OPC: A client-server model, where the server provides standard interfaces, enabling the client to control devices (PLCs, sensors, actors ...) and manage device data in a general manner [2]) starts to be used on a wide range. Moreover parallel to this the usually JAVA-based application of CORBA ("Common Object Request Broker Architecture" [3]) found its way from the office level to the shopfloor level.

Regardless of the advantages and limitations of DCOM and COBRA, and arguments based on companies philosophies, the features of both technologies can be put as following: they are perfect methods to build up "Multi-Tier" software-systems. In this case the Client-Server-System is structured in different levels ("Tiers") which are "logically" and "physically" separated (e.g. database access, program functions ("business rules") and user interfaces). Using appropriate tools (frameworks) for the development of software (e.g. Inprise MIDAS [4]) new types of distributed applications can be designed, communicating via DCOM and/or CORBA and/or directly via TCP/IP-sockets. Therefore, talking from the view of a software-designer, the above mentioned philosophical arguments loose its persuasiveness.

3. TARGETS

Based on the well known limitations of the existing systems ([5]) and the new technologies introduced in this article, the authors aim is twofold:


4. CONCEPT OF THE SYSTEM

The base of the system is a database which can be scaled according to the context's requirements and size of the system. The central processing- and information functions for all production- and machine-data, the configuration of the whole system and the validation of security/access permissions are provided by a server-program. This program accesses  the database and communicates with all clients via DCOM and/or sockets. The clients are lean Windows-programs, which mainly implement the user interface and simple validating functions.

The following key-features show the advantages of the system and bring the flexibility mentioned above:

4.1 System setup / maintenance

4.2 Operation of the system The concept is based (among other technologies) on TCP/IP. This has the effect, that almost all "Internet technologies" are easily to be integrated. Two examples: 5. SUMMARY

Basing on "new technologies" the above introduced concept for distributed machine- and production-data acquisition systems provides more flexibility and therefore creates various advantages. These have major effects regarding the implementation and operation of that kind of systems.
The tests of the implemented prototype-systems ([6]) gave proof of the concept developed by the author. At the moment the concept and the technologies are used in implementing two "real-world" shopfloor data acquisition systems.

6. REFERENCES

[1] Microsoft Corporation (1998). DCOM Technical Overview (White Paper),
http://msdn.microsoft.com/LIBRARY/CONF/HTML/S9CBF.HTM
[2] OPC Foundation (1999). OPC Specifications,  http://www.opcfoundation.org/specs.asp
[3] Schmidt, D.C. (1999). Overview of CORBA, http://www.cs.wustl.edu/~schmidt/corba-overview.html
[4] INPRISE Corp. (1999). MIDAS - Technical White Papers, http://www.borland.com/midas/papers/
[5] Kittl, B.; Baumann, C. (1999). Demands on Shopfloor Data Acquisition Systems, Proceedings of 10th International DAAAM Symposium, Katalinic, B. (Ed.), Vienna, October 1999
[6] Buell Informatik Ges.m.b.H (1999). Betriebsdatenerfassung (german), http://www.buell-informatik.at/prod/bde.htm

Authors:
Dipl.-Ing. Dr.techn. Christian BAUMANN, Phone: +43 1 588 01 31120, E-mail: baumann@mail.ift.tuwien.ac.at
A.o. Univ. Prof. Dipl.-Ing. Dr.techn. Burkhard KITTL, Phone: +43 1 588 01 31119 , E-mail: kittl@mail.ift.tuwien.ac.at
both: Institute for Production Engineering, Vienna University of Technology, Karlsplatz 13 / 311, A-1040 Wien, Fax.: +43 1 58801 31199, http://www.ift.tuwien.ac.at



Example: HTML-Interface for shopfloor-data information system:
HTML-Interface for SFDA-System