There is a way to get the password, but ethics will not let me divulge it, during a project to rip out some old systems & replace with new I came across a simular problem, however the one plc that was to remain in use on this site had been password protected by their own engineer whom had recently left, so the ethics did not apply & as we needed to make some modifications I promptly gained access & took the password out. I have been writing plc software for more than 20 years & have never "locked" any of the code I have produced, however this is mainly due to the fact that the code was written specifically for the client & as they paid for it, it rightly belongs to them & I do sympathise with a machine builder who builds standard machines where the development costs are spread across the sales & support of those machines.
But as for the companies or individuals whom get paid to produce one offs (as a lot of process plant is)by the customer surely then if they have paid for the software to be written, they should retain ownership. I have come across this & the usual excuses are "there is some complicated code in there & your engineers are not good enough to make modifications", "if your maintenance guys mess it up it will cost you more to call us out to put it right". quite frankly it is a way of trying to ensure that they & only they can extract more money out of you.
But personally I don't think it works, I know of a number of companies that will willingly pay for someone like me to dump the stuff that is full of bugs & re-write it.
