The engine needs an oil pressure gauge, coolant temperature gauge, hour meter, a charging meter where an engine-driven charger is required, and other maker-recommended instruments, on an enclosed panel near or on the converter that maintenance staff can read (on anti-vibration mounts if engine mounted). Panel wiring is harnessed or flexibly enclosed and secured against chafing. The set carries an engine-driven charger able to keep starting and control batteries fully charged while running; a Level 2 set may omit it if the automatic charger can recharge in time while carrying all battery loads.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.