Description And Operation: Notes
DESCRIPTION
Remote Compass Module Operational Video
On vehicles that are not equipped with a radio with an integral compass module, a Remote Compass Module (RCM) is used. This stand alone compass system is comprised of several different components. Those components are:
| 1. | Refer to BODY CONTROL MODULE (BCM) . |
| 2. | Refer to REMOTE COMPASS MODULE (RCM) . |
| 3. | Refer to RADIO . |
| 4. | Refer to INSTRUMENT PANEL CLUSTER (IPC) . |
The compass feature provides the customer with current information about vehicle heading. During normal operation of the compass, the compass feature displays the vehicle heading using one of eight octants: "N", "NE", "E", "SE", "S", "SW", "W" and "NW" or the equivalents for the various languages. If the magnetic reference point is lost, the compass module enters an auto calibration mode to reestablish a point of reference. However, the compass feature also allows the operator to manually calibrate the compass and manually change the variance of the compass. Refer to Uconnect® Settings in the Owners Manual for Compass Variance Adjustment and Manual Compass Calibration.
The compass module display is part of the IPC and radio (if equipped) and cannot be serviced as separate component. If the display is damaged or ineffective, the complete IPC or radio, whichever is damaged or ineffective, must be replaced. Refer to MODULE, INSTRUMENT PANEL CLUSTER (IPC), REMOVAL AND INSTALLATION and RADIO, REMOVAL AND INSTALLATION .
OPERATION
The BCM communicates with the RCM via a Local Interface Network (LIN). The radio and the IPC update the display heading at regular intervals based on CAN data from the BCM. The BCM sends the heading direction to the IPC and the radio via CAN.
When the vehicle starts and while the splash screen is active, the radio and the IPC do not show the compass direction for 2.5 seconds or until the splash screen is no longer active. When the vehicle starts and after the display of the splash screen, the radio and the IPC display the last known heading position until at least three valid signals are received. If the radio or the IPC didn't receive valid information from the BCM for 10 seconds, they will display "_ _".
The RCM determines the true north position using the earth's magnetic field and by applying the compass variance to determine the compass heading direction. The RCM provides hysteresis (the lag in the response of magnetic induction to changes of magnetic intensity) to prevent the display heading from switching back and forth repeatedly while driving along a switch point, for example, "N" and "NE". As part of the hysteresis, the RCM does not change the heading until the heading angle exceeds (or drops below) the normal switch point by 2.5 degrees or more. As an example: The switch point between North and North-East is 22.5 degrees. When driving "N" along that line, the RCM holds the heading "N", until the heading angle reaches 25 degrees, then it will update to "NE". Consequently, it does not change back to "N" until the heading angle drops below 20 degrees.