Download SIMATIC STEP 7

Using PLC Utilities
What to Do If You
Forget Your
Password
!
If you forget your password, use the master password CLEARPLC to gain
access to your PLC. You must set your PLC to the STOP mode, with the
switch in either the STOP or TERM position.
Caution
Using the master password CLEARPLC clears PLC memory and other user
data as described in the list below.
The use of the master password CLEARPLC can have unexpected results in
the operation of your PLC.
Take steps to keep your password in a secure place, and thus avoid the use of
the CLEARPLC password.
When you use CLEARPLC, the PLC is affected in the following ways:
S The PLC transitions to the STOP mode.
S The user program (OB1) is cleared (deleted).
S The user data memory (DB1) is cleared (deleted). All data space is
cleared.
S All configuration parameters except the station address are set to their
default state.
S All M memory bits are cleared.
S All SM memory bits are set to their default state.
S Analog outputs are frozen.
S All system data memory is set to the default state.
S All forced points are cleared and unforced.
S All timer and counter current data is cleared.
S The time-of-day clock (not supported by the CPU 210 and 212) is not
changed.
The results of using the CLEARPLC password can produce an unanticipated
side effect. The outputs change state when the PLC sets system data memory
to the default state. If you specified values other than the default, the values
will be set back to the default state.
Note
In a CPU with a memory cartridge installed, the PLC does not clear
information as described above. After you use the CLEARPLC password,
the memory cartridge data is not changed. To clear the memory cartridge,
you must copy the CPU contents to the memory cartridge.
STEP 7–Micro/DOS User Manual
C7900-G7076-C206-03
8-11