SIEMENS features

[Greg 0]

Good morning SIEMENS specialist's. i would be very pleased if you could answer me few question, i'm learning about STEP7 and s7-300, s7-400 PLC's especially about protection and security. 1. is there function of encryption/time stamp/signature? 2. TELNET command? 3. Master/Multi code, if i lock the CPU or any other feature with password and i forget it, is there a Master code to unlock it or could siemens do that? 4. status bit, that tells me if there were changes in PLC's configuration or the Code? Thousands thanks in advance for you guys/girls, for you help. Best Regards, Greg.

[JesperMP 2]

Hi greg. 1. Since STEP7 v5.5 and firmware on the CPU 3.2, there is a new "block privacy" function with a strong encryption. 2. Telnet is an arcaic internet protocol for exchanging simple text messages. Is this what you mean ? Anyway, there is no such funcionality in an S7 PLC. 3. In the documentation they say that "block privacy" code cannot be accessed without the password. So I guess that means "no". Or they are not telling. 4. There is both a CRC for the entire CPU, and timestamps for individual blocks. You would need to access the CPU with STEP7 to check these.

[Greg 0]

CRC, you mean Cycling Redundancy Check that used in communication protocols? and how can i check and research it without connecting a real CPU(i dont have one right now). and possibility to send the alarm/report or whatever it could be to control room. Edited 10 Nov 2010 by Greg

[JesperMP 2]

CRC can be used for anything. Not just communication. You can see the checksums for the HW Configuration and the user created code in Simatic Manager. Right-click on the Blocks folder under the selected CPU, and then select the Checksums tab.

[JesperMP 2]

Not sure if there is a possibilty to read the checksums with SFC51 RDSYSST. Or you can maybe read out the available number of memory bytes.

[Greg 0]

Thanks alot!