Protection Levels Of A S7-400 Cpu - Siemens SIMATIC S7-400 Reference Manual

Structure of a CPU 41x
Table 1-3

Protection Levels of a S7-400 CPU

Protection
Level
1
2
3
If different protection levels are set with the mode selector and with STEP 7, the
higher protection level applies (3 before 2, 2 before 1).
Operating Sequence for Memory Reset
Case A: You want to download a complete, new user program to the CPU.
1. Turn the switch to the STOP position.
Result: The STOP LED lights up.
2. Turn the switch to the MRES setting and keep it at this setting.
Result: The STOP LED is dark for a second, light for a second, dark for a
second and then remains on.
3. Turn the switch back to the STOP setting, then to the MRES setting again
within the next 3 seconds and back to STOP.
Result: The STOP LED flashes for at least 3 seconds at 2 Hz (memory reset is
executed) and then lights up permanently
Case B: When the STOP LED flashes slowly at 0.5 Hz, the CPU is requesting
a memory reset (system memory reset request, after a memory card has
been removed or inserted, for example).
Turn the switch to MRES and back to the STOP position.
Result:The STOP LED flashes for at least 3 seconds at 2 Hz (reset is being
executed) and then remains lit.
You can find the complete description of what happens during a memory reset in
the: S7-400, M7-400 Programmable Controllers Installation Manual, Chapter 6.
Cold Restart
The user program is started again following a cold restart. All the data, including
the retentive data, are deleted.
1-16
Function
•
All programming device functions are permitted
(default setting).
•
It is permissible to load objects from the CPU into
programming device. In other words, only read
programming device functions are permitted.
•
Functions for process control, process monitoring
and process communication are permitted.
•
All information functions are permitted.
•
Functions for process control, process monitoring
and process communication are permitted.
•
All information functions are permitted.
Switch Position
RUN-P/STOP
Automation System S7-400 CPU Specifications
A5E00165965-01
RUN
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