Steve Bailey
Lifetime Supporting Member + Moderator
krunalc is experiencing a bad time with passwords. It's probably worth a generic thread on the subject.
How do you feel about passwords? Do you use them? Are your opinions about people who use them printable?
Personally, I don't use them, but I can envision a few cases where I might be tempted to.
The first case would be if I had developed what I considered to be a proprietary algorithm that gave me a competitive edge. In that case, I'd put the algorithm in a subroutine, call the subroutine unconditionally from the main program, and password protect only the subroutine, leaving the rest of the program open to anybody for modifications as needed.
Another case would be to prevent unauthorized people from making changes, especially if there was a concern about someone changing the logic or the password out of malice.
If I were to use passwords, I'd be upset if the manufacturer of the PLC had provided a backdoor entry. That defeats the whole purpose of the password.
If you are an end user of equipment that includes a PLC, you can include a clause in your contract with the machinery builder that you be given any passwords. If you are contracting somebody to write PLC logic for you, include the same clause. You may find that the OEM or the programmer puts up a fight over the issue, but it's better to know about these things before you sign the contract, while you still have some leverage.
How do you feel about passwords? Do you use them? Are your opinions about people who use them printable?
Personally, I don't use them, but I can envision a few cases where I might be tempted to.
The first case would be if I had developed what I considered to be a proprietary algorithm that gave me a competitive edge. In that case, I'd put the algorithm in a subroutine, call the subroutine unconditionally from the main program, and password protect only the subroutine, leaving the rest of the program open to anybody for modifications as needed.
Another case would be to prevent unauthorized people from making changes, especially if there was a concern about someone changing the logic or the password out of malice.
If I were to use passwords, I'd be upset if the manufacturer of the PLC had provided a backdoor entry. That defeats the whole purpose of the password.
If you are an end user of equipment that includes a PLC, you can include a clause in your contract with the machinery builder that you be given any passwords. If you are contracting somebody to write PLC logic for you, include the same clause. You may find that the OEM or the programmer puts up a fight over the issue, but it's better to know about these things before you sign the contract, while you still have some leverage.