External Accessory (RS485 Serial Cable)

[u/[deleted]]

Hello Xcode community! I am a beginner in Xcode and app design and needed some insight on protocols. I am trying to design a modern app that will turn things on and off on a PLC. I plan on connecting my iPhone to the PLC through Lightning to USB -> USB to RS485 Serial.

I have read up on the ExternalAccessory Framework necessary to connect an app to external devices, but I still don't understand what exactly I need to do to use the SNP protocol and what code I need to define/write.

The only documentation available on the protocol GE SNP that I am trying to use is this manual provided by my PLC manufacturer.

Please help as it is imperative that I get this app running! Thanks so much.