Special Features When Backing Up And Restoring A Cpu - Siemens SIMATIC ET 200AL System Manual

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3.6 Secure Communication
Rules and recommendations
• Setting the password must be done in a secure environment.
• The content of the text file "PWD.TXT" defines the password for the protection of
confidential PLC configuration data. It must match the password that you have also
assigned in the CPU configuration.
• To reset an existing password of a PLC, the text file "PWD.TXT" must be empty, i.e. the file
size is 0 bytes.
• Use any text editor to create the text file. The recommended text format is "UTF-8".
• The folder and file names are not case-sensitive. However, the password itself is case-
sensitive.
• Do not enter a CR/LF character at the end (PWD.TXT or S7_JOB.S7S).
3.6.2.6

Special features when backing up and restoring a CPU

You can back up a functional configuration of a CPU in the TIA Portal and access it at a later
time; this means you can then restore the originally backed-up configuration. This allows you
to load a modified configuration, for example, to test product enhancements, to change
programs for troubleshooting in the system or you can replace components on a test basis.
You can then restore the originally backed-up configuration of the CPU.
Backing up the configuration
In backing up a CPU ("Online" menu, "Load backup from online device" in TIA Portal), the
password for the protection of confidential PLC configuration data is backed up as well.
Restoring the backup
When restore the backup of a CPU (menu "Online", command "Download to device" with
marked backup in TIA Portal) the CPU can only communicate with a PG/PC or HMI if the
following condition is fulfilled:
• After the restoration of a configuration protected with a password to protect confidential
PLC configuration data, exactly this password must be present in the CPU.
Otherwise the CPU cannot access the configuration data and therefore does not start.
Remedy
If the above error occurs, that is, the password for protecting confidential PLC configuration
data does not match the backup, you must delete the password to protect confidential PLC
configuration data in the CPU and then set the correct password. After a restart the CPU, the
backup is functional.
See also
Changing your password (Page 65)
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Function Manual, 05/2021, A5E03735815-AJ
Communication