Adjusting switch and controls illumination, function - GF54.30-P-2010R
MODEL 230
Signal flow diagram, terminal 58b
The brightness of the switch and controls illumination can be adjusted using the instrument illumination dimmer and reset button (A1r1) on the instrument cluster (A1). It is regulated based on the on/off ratio of terminal 58d (refer to separate section).
Signal flow:
- If the standing lamps are switched on, the driver-side SAM control module (N10/10) relays the message "Standing lamps ON" (1) over the interior compartment CAN.
- The instrument cluster (A1) receives this message and relays the signal "Terminal 58d on/off ratio" (2) as a message over the interior compartment CAN and the engine compartment CAN.
- Various control modules receive this message and actuate the lamps (L) of the switch and controls illumination with the square-wave voltage U58d .
Terminal 58d on/off ratio
The lamps of the switch and controls illumination are actuated with a square-wave voltage U 58d (see adjacent figure).
- The lamps are supplied with power during the time (t1) which is then followed by a pause. After the pause the lamps are energized again and so on.
The change occurs so quickly as to remain imperceptible to the human eye.
- The ratio of time t1 to time T is called the on/off ratio, where T is the constant cycle duration and t1 is the time during which power flows during a cycle.
- The higher the on/off ratio (i.e. the longer the power flow duration t1 ), the 1) greater the average power and therefore the brighter the lamps.
The figure shows the voltage curve U 58d as applied to the terminal 58d outputs of the various control modules. The upper curve represents an on/off ratio of 80 %, while the lower one represents an on/off ratio of 40 %.
An on/off ratio of 100 % corresponds to normal direct voltage. No voltage is supplied when the on/off ratio is 0 %.
Advantages of this type of brightness adjustment:
- Considerably more efficient
- The brightness of the lamps remains independent of the number of lamps
- Every control module connected to the interior compartment CAN or engine compartment CAN may actuate lamps with the intensity specified by the instrument cluster (A1).
When the standing lamps are OFF, the instrument cluster (A1) sends the message "Terminal 58d on/off ratio = 0 %". When the standing lamps are ON, the transmitted on/off ratio can be adjusted in the range from 12 % to 100 % using the instrument illumination dimmer and reset button (A1r1).
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