Buses and peripherals

The panel speaks Modbus on RS485 and Ethernet, raw CAN frames, MQTT for telemetry — and drives local chips over I2C and SPI. Every bus ends in the same place: the tag table. A value that arrived over Modbus looks exactly like one measured on a local pin, and the logic does not care which it was.

Modbus — RTU and TCP, master and slave, with a catalog of ready-made devices
Raw CAN — mapping CAN frames straight onto tags
MQTT — telemetry into ThingsBoard, OpenRemote or Home Assistant
Peripherals and services — expanders, converters, RTC time and the other on-board services
Adding a peripheral — the two-minute click-through, recorded