I have constructed a quality surveillance device based on RPi / python. The device is implemented on a factory. Now, the factory wants to set the sensitivity of the device from their factory PLC (a S7). So I need some communication between the two.
Now you think ethernet - but using ethernet in a factory environment is not easy here. Lots of firewalls and people who dont want the security risk.
However, if I could sneak the sensitivity signal through the digital ports of the PLC => RPi, nobody would care. I just want a number with 8-12 bit resolution through. there is plenty of time available as changes in sensitivity is associated with product changes with the line standing still.
I would like to send some kind of check or validation back from the RPi to the PLC for confirmation.
For some PCB reasons, I have 2 digital input ports and 3 digital outputs available on the RPi.
Anybody have some suggestions or experience on how to do this smart?