GF68.50-P-0004CA Roller Sun Blind, Function
GF68.50-P-0004CA Roller Sun Blind, Function
- with CODE (540) Roller sun blind
Function requirements, general
^ Circuit 15R ON
^ No overvoltage or undervoltage
The electronic ignition lock control unit (N73) transmits the circuit status of c. 15 to the interior CAN (CAN B).
Roller sun blind, general
The roller sun blind protects the vehicle occupants against dazzling and thermal radiation. It is located in the rear shelf and moves along the inside the rear window. A translucent piece of cloth is moved by a construction with a lever arm (articulated principle)
The roller sun blind is driven by the rear window roller sun blind motor (M24). The rear window roller sun blind motor is actuated by the rear SAM control unit with fuse and relay module (N10/2).
The roller sun blind is retracted or extended in the automatic mode without intermediate position.
The roller sun blind function comprises the following subfunctions:
^ Function sequence for retracting/extending roller sun blind
^ Function sequence for reversing roller sun blind
^ Function sequence for automatically switching off roller sun blind
Function sequence for retracting/extending roller sun blind
When the rear window roller sun blind button (N72/1s9) is actuated, the request to retract or extend the roller sun blind is read in by the upper control panel control unit (N72/1) and relayed to the front SAM control unit with fuse and relay module (N10/1) via the instrument panel LIN (LIN 1). It transmits a signal via the interior CAN to the rear SAM control unit, which actuates the rear window roller sun blind motor. The roller sun blind is retracted or extended to the end position depending on the direction is last moved.
The last direction of motion is stored in the rear SAM control unit, so that the roller sun blind is moved in the direction expected by the operator when the rear window roller sun blind button is actuated again.
Function sequence for reversing roller sun blind
If the rear window roller sun blind button is actuated a second time while a roller sun blind operation is already in progress, the roller sun blind stops and after t = 200 ms it is moved in the opposite direction.
Function sequence for automatically switching off roller sun blind
The partial function automatically switching off roller sun blind comprises the following subfunctions:
^ Function sequence for switching off with time control
^ Function sequence for switching off in event of blockage detection
^ Function sequence for switching off in event of hardware defect
^ Function sequence for switching off in event of voltage too high or too low
^ Function sequence for switching off with thermal protection
^ Function sequence for storing faults
Function sequence for switching off with time control
The rear window roller sun blind motor is actuated for t = 15 s by the rear SAM control unit regardless of the running direction of the roller sun blind. Under unfavorable conditions (e.g. cold, sluggishness) the actuation time is increased by t = 2 s.
After expiration of this time the actuation is automatically terminated.
Function sequence for switching off in event of blockage detection
When the roller sun blind reaches its end position from a current request or locks up for other reasons, an increase in power of the rear window roller sun blind motor is recognized and compared with the performance maps stored in the rear SAM control unit. the stored threshold value is exceeded, the rear window roller sun blind motor is switched off by the rear SAM control unit.
Function sequence for switching off in event of hardware defect
A request from the rear window roller sun blind button for t > 30 s is recognized as a "stuck" button by the front SAM control unit. The front SAM control unit does not output a signal via the interior CAN.
Function sequence for switching off in event of voltage too high or too low
If the on-board electrical system voltage drops or increases for t = 1 s below or above a certain value, the roller sun blind function is switched off.
If the on-board power supply voltage again reaches a permissible value for longer than t = 5 s, the roller sun blind function is switched back on.
If the voltage in the on-board electrical system is too low, the current request is accomplished up to the corresponding end stop for the roller sun blind.
Function sequence for switching off with thermal protection
A request from the rear window roller sun blind motor is stored in the rear SAM control unit. If more than one request is present within a specified time, they are listed and compared with the threshold value stored in the rear SAM control unit. If the threshold value is exceeded, the rear SAM control unit switches off the rear window roller sun blind motor to prevent overheating. A new request from the rear window roller sun blind motor is only possible after a cooling time stored in the rear SAM control unit.
Function sequence for storing faults
Malfunctions of the roller sun blind are stored in the fault memory of the rear SAM control unit. Relevant status data is stored her. This simplifies troubleshooting in event of implausible roller sun blind operation.
Following status data is stored:
- Function requirements
- Cause of last stop:
- Request during automatic mode
- Blockage detection
- Switchoff by timer control
- Switchoff by hardware fault
- Switchoff by overvoltage or undervoltage
- Switchoff when reaching target position
- Duration of actuation
- Actuation current
- Counter status of request
The stored status data can be read out using the diagnosis tester.
