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03/03
Supported FTP commands
After the HELP command is entered in the console box of the FTP client, a list of
the FTP commands supported by this client usually appears. While these com-
mands are being executed, they can then be converted internally by the FTP client
into subcommands and sent to the FTP server.
Some FTP clients on the market offer additional commands which are not included
in the RFC959 standard or whose specification is not generally binding. You can-
not be sure whether the FTP server on the CP 243-1 IT supports each of these
commands.
Communication partners
All FTP clients which communicate via Ethernet and which comply with RFC959
standards are always considered possible communication partners of the FTP
server located on the CP 243-1 IT. This means communication is not only possible
with PC-based FTP clients but also with S7-200, S7-300 or S7-400-supported FTP
clients, for instance.
Performance/general conditions
FTP communication is subordinate to S7 communication. This means that the re-
action times of FTP communication depend on the particular configuration and
cannot be generally specified in advance.
Note
Only one FTP client may access the FTP server at a time. When the FTP server of
the CP 243-1 IT is accessed by the S7 user program via the FTP client function, a
geographically remote FTP client cannot be accessed. The reverse also applies.
2.3.5
FTP Client
How it works
The FTP client of the CP 243-1 IT can be used to transfer parts of the DB in an S7-
200 system to the file system of an FTP server, or the contents of a file can be cop-
ied there to the DB of the local S7-200 system.
A distinction can be made as to whether a file is to be completely or only partially
transferred. The number of bytes to be transmitted can be specified in a read or
write job.
When 0 is specified as the number of bytes to be transferred in a write job, an
empty file with the name specified in the write job is set up in the file system of the
addressed FTP server. A length of 0 in a read job means that the specified file is
completely transmitted to the DB of the local S7-200 system if this does not exceed
its storage space. If the number of bytes to be read is specified for a read job, this
must match the length of the file to be read. If not, the CP 243-1 IT reports an error
when the read job is executed.
CP 243-1 IT
J31069-D0429-U001-A0-7618
Features and Functions
29
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