Displaying Time

Networking:

NOTE: The components identified with dotted lines are only of significance on vehicles with Comand (code 352).


General
For time measurement (time) a periodic process with a period of high accuracy is required (e.g. rotation of the earth, pendulum oscillation.)
An electrical clock signal with high-frequency accuracy is required for an electronic clock. This clock signal is mostly derived from the very constant mechanical vibrations of an oscillating quartz. Normally a quartz (1) with a very high frequency (several MHz) is used. This frequency is then divided down to the required frequency of 1 Hz using an electronic frequency divider (2). This means the display (3) receives an electrical pulse to switch on the display every second.

Displaying time on vehicles without Comand
The electronic clock (A1p6) works according to the above mentioned method.
In addition, electronics is still required for setting the clock. It is set via the "Settings menu" with the multifunction steering wheel pushbuttons:
- Scroll forward back pushbutton (S110s1)
- System selection pushbutton (S110s3)
- Pushbutton + and -, setting of specific functions and volume control (S111s1)
These pushbuttons are read in by the steering column module (N80) and passed on to the instrument cluster (A1) via the CAN interior.

NOTE: The instrument cluster (A1) also outputs the current time as a message on the CAN interior.


Displaying time on vehicles with COMMAND (code 352)
On vehicles with COMMAND the instrument cluster (A1) takes over the time from the COMMAND operating, display and control module (A40/3). Therefore the settings for the time take place there.
The time information is placed as a message on the CAN interior by the COMMAND operating, display and control module (A40/3). If the COMMAND equipment variant is coded in the instrument cluster (A1), it takes over this time information.
If GPS signals are received by the GPS antenna (A2/49a2), it is possible to change over from summer to winter time automatically.