Siemens Simatic S7-400

CPUs of the S7-400
2-4
Automation System S7-400 Configuration and Use
A5E0044271 1-02
Table 2-1 Protection levels of a CPU
CPU function
Protection level
1
Protection level
2
Protection level
3
Displays of the block list Access allowed Access allowed Access allowed
Tag monitoring Access allowed Access allowed Access allowed
S7 communication Access allowed Access allowed Access allowed
Read and set time Access allowed Access allowed Access allowed
Status block Access allowed Access allowed Password
required
Download program to
programming device
Access allowed Access allowed Password
required
Download program to CPU Access allowed Password
required
Password
required
Delete blocks Access allowed Password
required
Password
required
Download user program to
memory card
Access allowed Password
required
Password
required
Control tags Access allowed Password
required
Password
required
Bootstrap via programming
device
Access allowed Password
required
Password
required
If you do not know the password, you can remove the configured security level by
bootstraping the CPU using the operating mode switch. No flash card should be
inserted in the CPU.
Block Protection
You can protect individual blocks. The blocks can then no longer be opened. The
know-how contained in a block remains hidden to anyone not in possession of the
program sources.
Uniform Instruction Set
The STEP 7 programming package is used to program the S7-400. The STEP 7
instruction set is the same for every CPU. This compatibility means that user
programs can run on any CPU. The CPUs only differ in the execution time of the
instructions and the volume (see table 2-2).
The fault-tolerant CPUs of the S7-400H are also programmed with the same
instructions as the S7-400 CPUs. The functional differences between the S7-400
and S7-400H only involve the number of integrated functions and blocks.