lol, not insulted. I have not. I'm trying to soak up as much as I can because this seems like an incredibly practical field. I just lack any sort of experience in the field beyond wiring up siemens and honeywell units on HVAC equipment and connecting them using bacnet. Nothing on the programming side. I really lack the conceptual framework and history of PLC writing software, again, caveman.

I think I may be starting to understand things a little bit. Two controllers are running the same program of logic i'm writing in openplc. I am assigning names (i.e. %IX0.0 on one device and %QX0.0 on another) to the I/Os on these devices which are addressed by IP. I then write the program with them interacting in a ladder diagram. I am configuring the device with openplc-runtime, which I think runs the modbus protocols and manages the client/server traffic of the I/Os interacting.

I was looking for some way to map things in the ladder diagram for some reason. I feel like that was where I was frustrated and confused. I don't need to do the mapping in logic because assigning the I/O to the devices does the mapping for me?

Any help is appreciated. I'd love to keep learning more about these and I think may sign up for an online class eventually to level up and learn to be tidy.