Siemens S7 CPU Locked

I like the idea of having the comments loaded on to the MMC. This will make my job a lot easier.

As for the password thing... so what they are saying is that the password is in the software somewhere and not in the PLC as such. If the code is on the MMC somewhere that sets the password up then can it not be read / changed from Simatic Manager?

Second question is why would anyone password protect the PLC, it seems like a recipe for trouble to me..


:)
 
S7 CPU Locked

Thanks Johnny T,
Yes comments on the Micro Memory Card will be very useful.
However, there is a danger that sloppy programmers will not
keep their Step7 project up to date by continuing to make
online changes.
Regarding the password I think Siemens are saying it is stored
on the MMC as well as in the CPU. The CPU only has volatile memory and is not battery backed up. You set up the password under Step7 / Hardware / CPU properties and download the Hardware config to the PLC.
If the PLC is already password protected you can only do the download after you enter the correct password.
I prefer to not use passwords. Where it is necessary I use the same password everywhere and make it known to the customer. I am flattered if people copy my code and in any case continual development means that I offer new features on each job. Process improvement is a major aspect of my work. However, many companies feel they must protect their software investment and so put passwords on PLC's etc. The worrying aspect is that passwords are easy to put on a PLC and it can be done with mallice by for example a disgruntled employee. It can also be done by one company which has had a falling out with its customer.
Regards.............John Gaunt
 
Yep, I here ya!

Its exactly the same with things like OP7's. People like to password protect everything. Its fine if they just use the normal 100 password but they normally stick something in there and then by the time the customer has to work on it, the person who developed it has left.

I'm not a fan of passwords at all.

I'm surprised that there is not a way around the password protection in the PLC though. I'm assuming you need a password to upload the code to your computer.

Could you not make a new hardware config up in Simatic Manager and download it but choose not to overwrite the code thats in there? Or would it overwrite the code anyway..? I'm almost sure I've downloaded a new hardware config in the past and its left the existing code in the PLC..

You would then have an unprotected hardware config plus your original code..

:)
 
Originally posted by Johnny T

Second question is why would anyone password protect the PLC, it seems like a recipe for trouble to me

All our S7 PLC's that we used are password protected against read and write, no trouble there, the password is only known to authorised users, that's a total of two people!

Originally posted by Johnny T

Could you not make a new hardware config up in Simatic Manager and download it but choose not to overwrite the code thats in there? Or would it overwrite the code anyway..? I'm almost sure I've downloaded a new hardware config in the past and its left the existing code in the PLC

The options on password protection are write protect or read/write protect, so attempting to download a new configuration will end up with you being promted for a password, as write protect is always part of the options.
Apart from that, if you download the hardware configuration only it will leave your code in place, but you should download from the hardware configuration editor.

Paul
 
S7 CPU Locked

Thanks Johnny T and PLucas,
I have tried all the simple things. I still believe that Siemens have a way to get in but don't want to tell anybody. I am hoping someone will know about it and be prepared to assist.
Regards.........................John Gaunt
 
John

Almost certainly Siemenes will have a way in. But equally they will not want to release it. Think of the credibility they would loose with all their, say, OEM, customers who trust this password facility. If it turns out that anyone else can simply approach Siemens with a sob-story and say "Please unlock my PLC for me", where does that leave the poor OEM who reasonably placed his faith in a facility that was there to be used?

I would guess that Siemens' responsibility is presumably to ensure that you have a working PLC according to how they manufactured it. And this you can achieve by erasing everything. On the other hand, the software in the CPU isn't their's to release. Who owns it? Is it a machine builder, an integrator, an end-customer? What if the supplier's now bankrupt and out of business? Who owns his assets? The lawyers or administrators for the business? And you want to start handing it away? Wow, that's a murky pool to start paddling in. No wonder they don't want to get involved.

I just think there's at least two sides to this problem.

Regards

Ken.
 
S7 CPU Locked

Thanks Ken M,
I agree, there certainly are at least 2 sides to this issue.
I simply want to help out the owner of the PLC who has no way to contact the programmer who set the password.
Regards..............John Gaunt
 
John Gaunt said:
I have an S7-300 PLC that has had its CPU password protected.

Can anybody help me unlock it?

I don't have its Step7 project and want to download its
blocks, create a symbol table and be able to make some
necessary changes to its program. I am familiar with Siemens
Statement List (STL) programming.

Again, can you help unlock this CPU.

On password level you write"clearplc",maybe the password is
over write.This procedure maintain on SIMATIC S7 200 PLC.

Regards
Tarok Seal
India
 
S7 CPU Locked

Thanks tarok.seal,
I will give that a try and let you know if it works.

Incidentally I am about to leave for India to install a
couple of S7-400 systems near New Delhi.

Regards............John Gaunt
 
S7 CPU Locked

I have tried the suggestion by tarok.seal (entering clearplc as a password) but without success.
tarok.seal mentions using it with S7-200 which I understand uses a quite different version of Step7.
With Step7 ver 5.3 I can't find any place other than the password entry to enter clearplc.
Perhaps tarok.seal you can provide more information.
Regards................John Gaunt
 
I dont use S7-200, so I really dont know, but "clearplc" sounds more like it will erase the PLC memory, not like it will give access to the program.

Anyhow, I think that there should be no "back door" into a PLC that has been password protected. Do you want it to be possible for someone to enter your house with a "master key" that has been distributed to the public ?

It is certainly a hazzle for the enduser, but it is also very understandable that the supplier wants to lock the program while the equipment is still in warranty, and it is equally understandable if the supplier wants to protect his know-how from being copied by anyone.

If access to the program is required by the enduser, it must be aggreed upon when the equipment is purchased from the supplier.
 
Hi

What tarok.seal suggested definitely only applies to the S7-200. It has no relevance to the S7-300. I'm sorry, John. I would have warned about this earlier if I'd realised you were actually going to attempt it. The S7-200 and the S7-300 may as well be from different manufacturers for all they have in common.

See this link on the Siemens web-site - http://www4.ad.siemens.de/view/cs/en/17551345

Regards

Ken.
 
I found this on the same website posted by Ken M. It is for the S7-300. I don't know anything about the S7 plc's, I just happened to see this, maybe it will help.

Click Here for Link
 
Unfortunately, that only works for the older models with the keyswitch, not for the MMC based current models.

I discovered a guy on the German PLC forum, who claims to be able to clear the password, he didn't make it clear whether or not the programm is still there afterwards or not and the original inquirer only wanted to be able to download a new program.

This is his e-mail address: [email protected].

He wants to be paid for his trouble, but I guess that's not a seious problem if it's important enough to get access to the CPU again.

I assume he'll speak English, but if not send me a PM and I'll play go-between.

PS The post in the German forum is remarkably current - 13th & 15th of Dec.!
 

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