PLC-5 data file access

On page 12-5 of the Enhanced and Ethernet PLC-5 Programmable
Controllers manual it says quote

Important:
Removing both the read and write access from
a data table file prevents you from accessing
that file.

Unquote. Now, surely this can't mean that once you do this,
you can't reset the read and write access permissions, does
it?

Question #2: when you are setting read /write privileges
to program and data files, is this more or less protection
than checking the "deny future access" box, which from my
understanding means you have to have copy of the program on
floppy to go online with the PLC program?

I haven't used this in the PLC-5, but in the SLC the protection you are using is online protection only. Offline, you could still access these data files.

Not positive it works the same in the 5, but I'll give it a try in the morning to be sure.

For question #2, it is just protection. It is not the same as "deny future access".

OG

read and write prvileges are for exeuction of ladder files and external process selecting thos data elecments. this will not affec your ability to change the privilges.

jay

you DON'T want to go there ...

Greetings katratzi,



first of all, my advice is to leave this particular stone unturned ... in my opinion, it’s more trouble than it’s worth ... but ... if you want to do some research, this would be a good place to start ...








going further ... at first glance this looks like a good feature ... the basic idea is that you can separate your PLC workforce into four “classes” ... then you give each class their own password ... when it’s time to open a protected file, the software asks: “what class are you in? - and what is your password?” ... if the technician gives the right answers, then he can “read” and/or “write” the file - as you have previously selected ... sounds great doesn’t it? ...



now let’s leave this fairytale world and get back to reality ... six months after this program has been put in place, open the PLC enclosure and take a look ... smart money says that the various passwords will be written right inside the door with a magic marker ... open the laptop computer ... notice the yellow sticky notepad with all of the passwords written there ... open the technician’s toolbox and look inside the lid ... more passwords ...



get my point? ... the software/hardware works great ... but the people don’t take the system seriously enough ... when something’s broken at 3:00 in the morning, Engineer Ed doesn’t roll out of bed and drive to the plant just to enter his “TOPGUN” password ... instead he answers Technician Ted’s frantic phone call, swears him to secrecy, and then whispers the super-secret password ... then he rolls over and goes back to sleep ...



now let’s play hardball ... the highest level PLC dude is out of town and can NOT be reached ... the plant calls in an outside PLC vendor to help with an emergency plant shutdown ... oops! ... what are the passwords? ... this can be a VERY ugly picture ... let’s hope that they really and truly ARE scribbled in one of those places that I mentioned ...



as I said in the beginning, my advice is to leave this particular stone unturned ... in my opinion, it’s more trouble than it’s worth ...

thanks for the reply, Jay and Operaghost (cool name)


Ron- I see your point. maybe I will just do research and hold off
of implementation.