Siemens SIMATIC NET CP 243-1, Руководство по эксплуатации

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Application and properties
1.6 IT communication
CP 243-1
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Operating Instructions, 03/2012, C79000-G8976-C244-02
When a transfer between the FTP client of the CP 243-1 and an FTP server is interrupted, it
is possible that only parts of the transferred data are stored on the destination system. In
such cases, an error message is output in the S7-200 user program. The transaction is not
repeated automatically.
On the CP 243-1, data exchange via FTP is subordinate to S7 communication. Reaction
times vary with the particular configuration as well as the length of the S7-200 application
program and it is not possible to make a generalized prediction.
Note
The file DB mechanism of the CP 343-1 IT and CP 443-1 IT communications processors is
not supported by the CP 243-1. The CP 243-1 reads or writes one binary image of the data
block to or from a file. This file contains no other information about lengths, source
addresses etc.
1.6.6 HTTP server
Basics
Java applets are small application programs created in the Java programming language. At
a browser's request, such applets are usually transferred from an HTTP server to a browser
and executed there. The browser must be capable of handling Java and must permit
execution of applets. Most browsers used today are Java compliant. 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 to create complete Java
applications or Java applets.
How it works
The HTTP server functionality integrated on the CP 243-1 permits the user to access the S7-
200 system with most Web browsers and to read status information and read or change
process values.
To do this, the user can make use of predefined HTML pages and Java applets stored in the
file system of the CP 243-1. Users can also create their own HTML pages or Java applets
and transfer them to the file system of the CP 243-1 using an external FTP client.
To simplify the creation of Java applets, you can download ready-made Java Beans from the
Internet pages of Siemens Automation Customer Support at the following address:
22964892 )
On the Internet page, select the "Entry list" tab and the "Download" entry type.