networks//network protocols//CAN//J1939

A higher-layer protocol on top of CAN, standardized by SAE for heavy vehicles and mobile machinery: trucks, buses, agricultural and construction equipment.

A higher-layer protocol on top of CAN, standardized by SAE for heavy vehicles and mobile machinery: trucks, buses, agricultural and construction equipment.

It fixes what raw CAN leaves open: which identifiers mean what, how parameters are grouped into messages, how nodes are addressed and how larger data is split across frames. Engine speed, coolant temperature or fuel rate have the same identifiers on any compliant vehicle.

It is the vehicle-world answer to the same question Modbus register maps and OPC UA information models answer in the plant: raw transport plus an agreed vocabulary (register map).