Electrical system isolation in event of closed-circuit current violation

The following text shows how the power module (PM) behaves

• in the event of different closed-circuit current violations
  
• and logged-on stationary consumers.
  

The current values used in the illustrations are only to be viewed as tendencies (e.g. between 10 A and 20 A or between 5 mA and 10 mA).

Normal sleep procedure without closed-circuit current violation

Sequence, normal sleep procedure:

• Terminal R off or change of flaps or ZV status
  CAN bus goes to sleep after a few minutes
  
• After 16 minutes, the signal ”CS off” is transmitted by the PM
  the bus is thus woken briefly
  the CS_roof output is shut down
  the bus goes to sleep
  
• After 60 minutes, the CS_body output is shut down
  the CS_body relay drops out
  the PM assumes the closed-circuit current monitoring function
  

Sleep behavior with closed-circuit current violation after 120 minutes

Sequence in event of a closed-circuit current violation after 120 minutes:

• Terminal R off or change of flaps or ZV status
  CAN bus goes to sleep after a few minutes
  
• After 16 minutes, the signal ”CS off” is transmitted by the PM
  the bus is thus woken briefly
  the CS_roof output is shut down
  the bus goes to sleep
  
• After 60 minutes, the CS_body output is shut down
  the CS_body relay drops out
  the PM assumes the closed-circuit current monitoring function
  
• Closed-circuit current violation (I> 80 mA)
  5 minutes waiting period. In this period, the current is measured by the PM every 1.5 seconds. The electrical system has the option of accepting a normal closed-circuit current in this period. If a current is detected during the waiting period which is OK over a period of 1 minute (codable), the waiting period is restarted.
  In the current path shown, the closed-circuit current violation remains at the end of the waiting period.
  
• A fault memory entry is made
  the shutdown counter starts for 90 seconds
  the electrical system is isolated briefly
  
• If the closed-circuit current violation is still present
  the shutdown counter is started a second time for 90 seconds
  
• the electrical system is isolated
  

The electrical system is closed again by the following events:

• Change to terminal R or terminal 15
  
• Operation of battery switch
  
• Signal to terminal 15 wakeup line
  
• External charging detection
  
• CAN message on activated statutory consumers
  

Sleep behavior with logged-on stationary consumer:

• with terminal 0 (terminal R and terminal 15 off)
  
• and excessive closed-circuit current
  

Sequence with logged-on stationary consumer:

• Terminal R off or change of flaps or ZV status
  CAN bus goes to sleep after a few minutes
  
• After 16 minutes, the signal ”CS off” is transmitted by the PM
  the bus is thus woken briefly
  the CS_roof output is shut down
  the bus goes to sleep
  
• Stationary consumer logs on (in the example at hand 30 minutes after terminal R off).
  The PM permits the log-on provided the battery charge state is still sufficiently high. The consumer is entered in a list in the PM.
  If the battery charge state drops during operation of the stationary consumer to such an extent that starting capability is jeopardized:
  
  • the telegram Stationary consumer off is transmitted on the CAN bus
    
  • the electrical system is isolated after 5 minutes
    
  • and the CC message ”Recharge battery” is issued
    
• Stationary consumer logs off (telephone, transmission)
  Closed-circuit current violation (I> 80 mA)
  5 minutes waiting period. In this period, the current is measured by the PM every 1.5 seconds. The electrical system has the option of accepting a normal closed-circuit current in this period. If a current is detected during the waiting period which is OK over a period of 1 minute (codable), the waiting period is restarted.
  The waiting period is normally 5 minutes. If however the telephone or the transmission is logged on as a stationary consumer, the waiting period is 10 minutes.
  In the current path shown, the closed-circuit current violation remains at the end of the waiting period.
  
• A fault memory entry is made
  the shutdown counter starts for 90 seconds
  the electrical system is isolated briefly
  
• If the closed-circuit current violation is still present
  the shutdown counter is started a second time for 90 seconds
  the electrical system is isolated
  

Sleep behavior with logged-on stationary consumer:

• with terminal 0 (terminal R and terminal 15 off)
  
• without closed-circuit current violation
  

Sequence with logged-on stationary consumer:

• Terminal R off or change of flaps or ZV status
  CAN bus goes to sleep after a few minutes
  
• After 16 minutes, the signal ”CS off” is transmitted by the PM
  the bus is thus woken briefly
  the CS_roof output is shut down
  the bus goes to sleep
  
• Stationary consumer logs on (in the example at hand 30 minutes after terminal R off).
  The PM permits the log-on provided the battery charge state is still sufficiently high. The consumer is entered in a list in the PM.
  If the battery charge state drops during operation of the stationary consumer to such an extent that starting capability is jeopardized:
  
  • the telegram Stationary consumer off is transmitted on the CAN bus
    
  • the electrical system is isolated after 5 minutes
    
  • and the CC message ”Recharge battery” is issued
    
• Stationary consumer logs off
  In the current path shown, the closed-circuit current is OK after shutdown of the stationary consumer.
  

Sleep behavior with logged-on stationary consumer:

• With terminal R
  

With terminal R, the stationary consumers may only be operated for such a period of time which does not jeopardize starting capability.

If the battery charge state drops during operation of the stationary consumer to such an extent that starting capability is jeopardized:

• the telegram Stationary consumer off is transmitted on the CAN bus
  
• the electrical system is isolated after 5 minutes
  
• and the CC message ”Recharge battery” is issued
  

Stationary consumers

The following control modules log on and off with the PM as stationary consumers.

• Trailer Module
  
• Control Display
  
• Light module
  
• A/C control module
  
• Transmission control module
  
• Telephone
  

Trailer Module

The trailer module logs on with the PM for the following functions:

• Sidelights
  
• Parking light
  
• Hazard warning lights
  

Control Display

The control display logs on with the PM as a stationary consumer under the following conditions:

• by pressing the volume control button on the audio system controller
  and then operating the controller
  
• or in the event of an incoming call (with telephone switched on)
  

Light module

The light module logs on with the PM as a stationary consumer for the following functions:

• Sidelights
  
• Parking light
  
• Hazard warning lights
  

A/C control module

The A/C control module logs on with the PM as a stationary consumer for the following functions:

• Independent heating
  
• Independent ventilation
  
• Residual heat
  

Transmission control module

The transmission control module logs on with the PM as a stationary consumer under the following conditions:

• Engine OFF
  
• Selector lever position N
  

Functional sequence:

• The parking gear in the transmission is held open by a holding magnet
  
• after 30 minutes a CC message is issued to the effect that the parking gear is being engaged
  
• then the parking gear is engaged after 5 minutes have elapsed
  
• the transmission control module logs off as a stationary consumer
  

If during these 5 minutes one of the following actions is performed

• Operation of selector lever
  
• Opening/closing of driver's door
  
• Unloading/loading of driver's seat occupancy
  

the 30 minutes are restarted.

If the battery charge state drops during the restarted sequence to such an extent that starting capability is jeopardized, the time is reduced from 30 minutes to 5 minutes.

If selector lever position P is engaged after the engine has been switched off:

• the parking gear is engaged
  
• the transmission control module does not log on with the PM as a stationary consumer
  

Telephone

The telephone (ECE and US) logs on with the power module as a stationary consumer for the following function:

• Timer
  

The charging tray for charging the keypad handset is supplied via body consumer shutdown for 60 minutes.

Special case, instrument cluster

After the vehicle is stopped (engine off), the value of the outside temperature sensor is interrogated every 10 minutes for the purpose of determining the outside temperature. No other bus is woken by the instrument cluster for the purpose of interrogating the outside temperature sensor.

For the purpose of calculating the outside temperature, the coolant temperature is also included by the engine (waste heat from the engine affects the outside temperature sensor).

The coolant temperature is interrogated by the instrument cluster.

• The CAN bus is woken by the instrument cluster
  
• The coolant temperature is interrogated by the engine control module
  
• The CAN bus goes to sleep
  
  

Bus wakeup times for determining coolant temperature

The time for interrogating the coolant temperature with bus waking and bus sleeping is below 5 minutes. Thus the sequence lies within the waiting period of the PM.

The instrument cluster does not have to log on with the PM as a stationary consumer.