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CJ1M password protection

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#1 benbrad

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Posted 11 January 2006 - 10:19 AM

I've been asked today to lock a CJ1M 23 ready for despach to an ex-competitor. Our company is now on friendly terms with our Russian counterparts and the powers that be have agreed to send them some of our machines on licence.

I've had to build an encrypted key into the code so that every month (provided we're still on good terms with them) they can enter a new key and the machine will run for another month.

I've never used the password facility as everything here is "in-house", and I'm a bit concerned as to how easy it might be to break into the code and disable the licence section.

Does anybody have any idea as to how hard this is to do?
Is there a way of automatically erasing all the code should someone illegally attempt to access it?

Thanks in advance

benbrad

#2 PdL

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Posted 11 January 2006 - 10:52 AM

Hi Ben,

Here are some pages from the programming manual about protection.
Never used protection myself.
I recall the CPU locks itself after 5 false password attempts but I don't know if this is also the case with CJ1M.

Alternatively there is a function that replaces complete program with a pre stored program on a memory card.

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#3 ECSI

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Posted 11 January 2006 - 11:29 AM

PDL, I believe there is an misprint in Note 2 of your attached pdf file. The word 'cannot' should be 'can' instead.

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#4 PdL

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Posted 11 January 2006 - 12:44 PM

PDL, I believe there is an misprint in Note 2 of your attached pdf file.  The word 'cannot' should be 'can' instead.

Thanks for pointing that out ECSI, it's extracted from the CJ/CS series programming manual.

#5 Guest_anonymous_*

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Posted 12 January 2006 - 04:38 AM

I've never used the password facility as everything here is "in-house", and I'm a bit concerned as to how easy it might be to break into the code and disable the licence section.

Hello benbrad,
If you search the forum (and not just this one), you'll find that people have quite a lot of trouble 'cracking' PLC password protection.
The CS / CJ series use an 8 digit alpha-numeric password, so that leaves quite a lot of possible combinations! And you can password protect individual tasks within the PLC as well, making it 'doubly' difficult to get at your program.
I'm not saying that it is impossible to crack the password protection (nothing is totally failsafe), but it would require either real specialist knowledge of the PLC's internal memory set-up, or total determination / luck to by-pass it.

Hope this helps quell any concerns you may have.

Regards
anonymous

#6 benbrad

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Posted 12 January 2006 - 06:38 AM

Thanks all for your input.

Read the manual now, absorbed some of it.

What happens after too many wrong password entries? It doesn't have to go off to Omron for repair, does it?

#7 Guest_anonymous_*

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Posted 12 January 2006 - 07:50 AM

What happens after too many wrong password entries? It doesn't have to go off to Omron for repair, does it?

Hello benbrad,
I think this may confound a few people, but no, as far as I am aware, the idea of 'x' number of tries to release the password before it locks you out completely is a total myth.

Just to make sure, I've just tried 20 or so incorrect attempts on a CJ1M - could still release it using the correct password. :wooted:

Regards
anonymous

#8 benbrad

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Posted 12 January 2006 - 10:56 AM

Cheers anonymous

I'd have tried that myself but for fear of doing something I would later regret.

Ben




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