Casing tube module function - GF54.21-P-4104-04S

Model 215, model 220 

With the exception of the switch for cruise control with variable speed limiter (S40/4)  all switches and pushbuttons that can be read in from the steering column module (N80)  are read in as coded voltages  .

This procedure has the following advantages:

• the number of plug connections is greatly reduced,
• the design can be distinctly smaller on account of smaller plug connections,
• contacting problems are minimized.

Voltage-coded reading in of pushbuttons on steering column module's multi-function steering wheel: 

Several particularities must be observed when voltage coding the multi-function steering wheel's pushbuttons:

• All the multi-function steering wheel's pushbutton contacts are read in by the steering column module (N80) via 2lines only. (The 3rd line is for the pushbutton-unit illumination.)

  If the voltage coding took place solely by way of different resistors in corresponding graduations, then an appropriately high interference resistance could no longer be guaranteed. For this reason the pushbuttons are read in as follows:

  The steering column module (N80) generates a voltage which constantly changes its polarity  for the purpose of testing the pushbuttons.

  The pushbuttons on the multi-function steering column are split up into two groups  (left and right multi-function steering wheel pushbutton groups (S110, S111) with the respective pushbuttons for the fanfare horns).

  These pushbutton groups have one diode each  connected in series, with a different polarity for each group.

  The right or left pushbutton group is alternately queried, depending upon the polarity of the test voltage from the steering column module (N80). The pushbutton contact query "switches" back and forth between the two switching groups  . The actual voltage coding is conducted solely within one of the pushbutton groups.

• If within one of the pushbutton groups  for the multifunction steering wheel several pushbuttons  are actuated simultaneously, the steering column module (N80) always issues a message for one function  to the CAN interior! This results in different valances  for the various functions within a single pushbutton group. The pushbutton with the lowest resistance value has the highest valence  .
• Valences for the pushbutton functions within the right multi-function steering wheel pushbutton group (S111) : 
  1. "Fanfare horns" pushbutton function
  2. "Terminate phone call" pushbutton function
  3. "Accept phone call" pushbutton function
  4. "a" pushbutton function
  5. "+" pushbutton function

  Example: 

  If the "terminate phone call" pushbutton and the "a" pushbutton are pressed simultaneously, only the "terminate phone call" pushbutton operation is forwarded to the CAN!

• Valences for the multi-function steering wheel pushbutton functions within the left-hand pushbutton group (S110) : 
  1. "Fanfare horns" pushbutton function
  2. model 220 up to 31.5.00: pushbutton function "voice control system"
  1. 2. Model 215 and as of 1.6.00 model 220: "System selection, scroll backwards" pushbutton
  2. 3. "System selection, scroll forwards" pushbutton
  3. 4. "Scroll backwards" pushbutton
  4. 5. "Scroll forwards" pushbutton