Alternator actuation (bit-serial data interface)

The following functions have been implemented in the DME control unit for the alternator with bit-serial data interface (BSD):

• Switching the alternator on and off using defined parameters
• Specification of the alternator's maximum permissible power consumption
• Calculation of the input torque for the alternator based on the power consumption
• Control of the alternator's response when higher electrical loads are connected (load-response function)
• Diagnosis for the data line between the alternator and DME control unit
• Storage of faults which develop in the alternator in the fault memory of the DME control unit
• Actuation of the charge-current indicator light in the instrument cluster via bus connection
• Introduction of intelligent alternator regulation:
  • from 03/2007 in the E60, E61
  • from 09/2007 in the E63, E64, E70

The principal function of the alternator is also guaranteed when communication between the alternator and DME control unit is interrupted.

The following fault causes can be distinguished in fault memory entries:

• Overheating protection:

  The alternator is overloaded. For safety reasons, the alternator voltage is reduced until the alternator has cooled down (charge telltale light does not light up).

• Mechanical fault:

  There is a mechanical block in the alternator. or: The belt drive is defective.

• Electrical fault:

  Excitation diode defective, excitation coil has been interrupted, overvoltage due to defective governor.

• Communication failure:

  Line between DME control unit and alternator defective.

An interruption or short circuit in the alternator coils will not be detected.