Accessing system variables through CIP Explicit message

please read pinned topic READ FIRST. you really need to mention details of software versions and manuals you are working with.

well, you may cry all you want but i don't think responding to vague "what is the meaning of life" kind of questions is productive. if user is not willing to reveal some relevant detail, he does not really deserve help.

the fact is that there are different controller generations and many things including fieldbus/connectivity are not the same.

here is a one example of on demand reading/writing of pretty much anything: