I'm just getting started with 800xa/Mod300. Brand new to process engineering too. ;) Learning quickly, but there is a ton to sort through.
Q: How can i modify a graphic to display a PID setpoint value on an operator screen? 'Someone' keeps changing the value(we'll try to identify who) and we want to be able to see the setpoint without having to click and open other windows.
There are several solutions to your problem. If legally allowed you can enable audit trail it will present you in an event list which account, on which 800xA computer, at which date and time changed the setting.
You could set the pid parameters to a more restricted permission e.g. download so only application engineering group members can change these.
For the graphics yes it's possible you add a text element to the graphics and browse for the pid variable. How depends on if you visual basic or pg2 graphics.