User interfaces of an MES system

One fundamental feature of MES systems is their user interfaces. The most important areas of application include, on the one hand, specialized inter-faces for use in production. On the other hand, an effective configuration of the system should be possible, as also a clear presentation of the data col-lected. The section will deal with the technical possibilities and in particular also with the benefits which MES systems can offer users at this point.

5.3.1 Technologies for user interfaces Local client

This technology exists in several forms, ranging from the simple cli-ent/server system to distributed applications in which part of the applica-tion is no longer executed in the client.

The advantages of this solution:

 There is good exploitation of local resources;

 Communication only occurs in relation to data exchange;

 Complex applications can be realized without any problem.

The disadvantages of this solution:

 High administrative cost;

 High costs per client.

Thin client

In contrast to the local client, with a thin-client solution only a kind of interpreter is used in the local workplace computer. Both the interface and the data are first sent to the client where they then together define the ap-plication. By means of local data storage strategies at the client end, long-ish waiting times as the data are loaded are reduced.

The advantages of this solution:

 Lower administrative cost;

 Low costs per client.

The disadvantages of this solution:

 Complex applications take a lot of time and effort to set up;

 High requirements as regards the LAN infrastructure;

 Limited possibilities in the graphical representation of technical situa-tions.

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Windows Terminal Server and Citrix solutions

These solutions are based on the strategy of combining the advantages of the two solutions just mentioned. Normal applications are used (local cli-ents) which are however run on special servers. The only thing now left running on the local workstation computer is a special client which no longer interprets the data and the application but only receives and displays screen output data from the server and, in the other direction, sends user inputs from, for example, keyboard and mouse to the server. This combi-nation makes it possible for complex applications to be run on less power-ful workstation computers. In addition, it delivers reductions in administra-tive costs since the application only needs to be installed on the server.

Smart clients

Microsoft is currently publicizing its new development framework .NET.

With this development framework so-called smart clients can be created.

During the development process the developer specifies which parts will run locally and which parts will run on the server, which means that the applications appear to be a mixture of local client and thin client. Another outstanding feature of smart clients is that no separate installation routines are now required: instead, administering these systems is made easier by software distribution by copy command.

5.3.2 User interfaces for configuration, monitoring and reporting

In many cases the operating system Microsoft Windows in its current ver-sion of Windows XP is used as a platform for the fields of configuration, monitoring and reporting and is regarded as industrial standard. As regards the technology for the user interface, all of the possibilities we have men-tioned are candidates. If a correct selection of technology is to be made, the benefits of the application should stand in the foreground. There is no doubt that web solutions will suffice for information workstations and simple controlling. On the other hand, even in the very near future, a local client will be required by complex applications such as control stations, planning modules or applications with special requirements regarding ef-fective working.

The user interface of an MES should have the following important properties:

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 Easy adaptability of the interface for customer-specific wishes by means of, for example, user fields;

 Powerful tools for creating customer-specific reports;

 Powerful tool for creating complete customer-specific applications (ap-plication designers);

 As has already been explained previously, here too the correct combina-tion of technology and applicacombina-tion offers the best possible benefits for the user.

5.3.3 User interfaces for data collection

Special requirements made of the user interface

In the area of data collection, in addition to the rapid and effective acquisi-tion of data, displaying the actual situaacquisi-tion stands in the foreground. As part of the shift of responsibility in production towards the workers (group work, for example) or due to attempts to make savings, reporting in the area of data collection is however becoming more and more important.

This means that comparisons with the previous day or week are already possible on the operational level. For the reasons we have mentioned, Windows or Windows CE systems (CE for consumer electronics, systems for smaller applications) is being used more often, even in the area of data collection, since the presence of a graphical interface means that more information can be displayed.

In addition, these operating systems form a good basis for networking in the local network as well as permitting easy inclusion of printers. Good net-working capability gives Windows-based systems decisive advantages in the growing segment of WLAN interfacing. In this case the advantages of

“mobile data collection” and “online data access” can be combined together.

The data collection devices are operated manually via special keyboards integrated in the housing or via touchscreens. In addition, the most varied reading systems are used for bar codes, RFIDs or other identification vehi-cles, including even biometric recognition.

One argument used in favor of Windows-based data collection systems is that investment is protected as this equipment is supported by virtually all MES systems. On the other hand, there is a large market for special terminal solutions based on other operating systems which will principally be used when requirements are simpler or when the costs of each data col-lection device have to be kept low.