Ethernet CP as FTP server for the CPU data - STEP 7

Communications modules and network components

ft:publication_title
Communications modules and network components
Product
STEP 7
Version
V20
Publication date
11/2024
Language
en-US
Ethernet CP as FTP server for the CPU data

Reference

Data acquisition for automatic creation of a file allocation table in the "Properties > General > FTP configuration" parameter group.

With the information in the file allocation table, it is possible to address data blocks in one or more CPUs (up to 4) in an S7 station.

"Activate FTP server" option (only with certain CP types)

Select this option to allow FTP access to the S7 station via port 20/21 of the CP.

This option needs to be enabled to enable FTP access to file DBs on the CPU with the option described below.

FTP server access via Port 20/21 is enabled by default.

"Use FTP server for S7 CPU data" option

If you select this option, the file allocation table configured here is created on the CP when you download the project engineering data and store it in the /config folder of the file system of the CP.

An existing file_db.txt file is overwritten.

Note

With security and the "Allow access only via FTPS" enabled, the following applies:

  • The files are transferred encrypted.

  • For the user, the rights "FTP: Read files (DBs) from the S7 CPU" or "FTP: Write files (DBs) from the S7 CPU" must be activated.

  • If the firewall is activated, the FTP/FTPS protocols must be allowed.

Ethernet CP as FTP server for the S7 CPU data

To transfer data using FTP, you create data blocks on the CPU of your S7 station; due to their special structure, these are known here as file DBs.

When operating as an FTP server, if the Ethernet CP receives an FTP command, it checks a file allocation table (file file_db.txt) to find out how the data blocks used in the S7 station for file transfer are mapped to files.

You can create the file allocation table and transfer it to the CP as follows:

  • With an entry in the parameter group "Properties > FTP configuration" described here

    The file allocation table is then created in the FTP configuration based on this information and downloaded automatically to the CP along with the configuration data.

  • By creating a file_db.txt file directly

    If you create the file allocation table in this way, you will need to load it to the CP using an FTP command.

The file allocation table file_db.txt is stored in the file system of the Ethernet CP in the /config directory.