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03/03
2.3.6
HTTP Server
Fundamentals
Java Applets are little application programs prepared in the programming language
Java. At a browser's request, such Applets are usually transferred from an HTTP
server to a browser and executed there. The browser must have Java capability
and must permit execution of Applets. All today's browsers usually offer Java ca-
pability. They can usually be configured to allow execution of Java Applets.
Java Beans are software components with a standardized interface written in the
programming language Java. It is easy to link these Beans into conventional Java
development environments and connect them with graphic tools for complete Java
applications or Java Applets.
How it works
The functionality of an HTTP server integrated on the CP 243-1 IT permits the user
to access the S7-200 system with one of the popular Web browsers to read status
information or read/change process values, for instance.
Predefined HTML pages and Java Applets stored in the file system of the CP 243-
1 IT are available to the user. In addition, the user can prepare his own HTML
pages or Java Applets and transfer them to the file system of the CP 243-1 IT with
the help of an external FTP client.
Java Beans are provided on the documentation CD of the CP 243-1 IT for simple
creation of Java Applets. They can be copied from there to a development com-
puter and then, with the aid of a Java development environment (e.g., "Visual Age"
from IBM), linked to your own Java Applets. The Beans included with the CP 243-1
IT are Java components which provide functions which can always be used when
creating a user interface environment. This not only includes functions for read or
write accesses to individual process values but also graphic functions for visualiza-
tion of such values.
The document "SIMATIC NET IT-CP Programming Help" included with the CP
243-1 IT on the documentation CD contains a more detailed description of the indi-
vidual Beans. A precise description of how to combine these Beans into Java Ap-
plets is provided. If the Java Beans described in this document are used with the
purpose of accessing an S7-200 via a CP 243-1 IT, symbolic addressing cannot be
used in these Beans.
Using the HTML pages and Java Applets supplied in the file system of the CP 243-
1 IT, the following data areas and data types of the S7-200 system can be ac-
cessed.
− Data types
BOOL, BYTE, CHAR, WORD, INT, DWORD, DINT and REAL
− Data areas
Inputs (I), outputs (Q), markers (M), variable area (V) and special markers
(SM)
CP 243-1 IT
J31069-D0429-U001-A0-7618
Features and Functions
33
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