Description
Instrument Cluster
NOTE:
A = Hardwired; D = High speed CAN bus; N = Medium speed CAN bus; O = LIN bus; P = MOST; AE = LVDS signal
OPERATION
Vehicle Interface
Then instrument cluster receives a permanent power supply from the vehicle battery via a 50A midi-fuse located in the BJB (battery junction box) and then CJB (central junction box). The cluster also has a connection with the CJB (central junction box) for the security LED (light emitting diode) operation.
The instrument cluster communicates with other vehicle systems via the medium speed CAN (controller area network) bus, the high speed CAN (controller area network) bus and the Media Oriented System Transport (MOST) ring. The cluster is not a gateway for these interfaces; this task is performed by the CJB (central junction box).
The instrument cluster is connected to the Touch Screen Display (TSD) by a Low Voltage Differential Signalling (LVDS) digital video screened cable. This connection is to support the detailed satellite navigation maps displayed in the instrument cluster.
A single wire from the instrument cluster to the electric steering column lock provides a ground for the lock operation. Power supply and control for the steering column lock is provided by the CJB (central junction box) via hardwired connection and a high speed CAN (controller area network) bus connection.
Cooling Fan
The cooling fan operation is controlled by the instrument cluster. The cooling fan receives a power supply via a 10A mini fuse in the CJB (central junction box). Three additional wires connect the fan to the instrument cluster; one for a fan PWM (pulse width modulation) for fan speed, one for a monitor signal and a ground.
The instrument cluster monitors its internal temperature and also receives temperature information from the TSD. If one or both of these temperatures exceeds a predetermined value, the instrument cluster operates the cooling fan.
The instrument cluster can control the speed of the fan motor and hence the air flow to both the cluster and the TSD, via air ducting, by varying the PWM (pulse width modulation) signal to the motor.
At temperatures of up to 40°C (104°F) the cluster operates the fan motor speed at a duty cycle of 30%. as the temperature increases, the duty cycle is increase linearly up to a 100% duty cycle at temperatures of 60°C (140°F).
The monitor connection between the fan and the instrument cluster is used by the cluster to detect fan faults (for example a blockage). Any faults are recorded as a DTC (diagnostic trouble code) in the instrument cluster.
When the TSD requires cooling a request is sent from the TSD on the medium speed CAN (controller area network) bus to the instrument cluster. The instrument cluster uses the information from the TSD to operate the fan at the required speed using PWM (pulse width modulation).
If the TSD or the instrument cluster are individually requesting cooling fan operation, the fan request is granted for that components requirements. If both the TSD and the instrument cluster both request fan operation, the fan duty cycle is set to operate to the greater of the two requests.
Right Hand (RH) steering wheel mounted switch assembly
A LIN (local interconnect network) bus connection from the clockspring to the instrument cluster receives signals from the RH (right-hand) steering mounted switch assembly.
The switch assembly contains a control module. The module outputs a reference voltage to the joy pad in the RH (right-hand) steering wheel switch assembly. The switches in the switch assembly are connected through several resistors in series to a ground point. The control module monitors the resistance in the switch circuit to determine the selected switch function.
When a switch is operated (switch contact momentarily closed), the control module senses the change in resistance and determines the requested function by the measured resistance value. The control module converts this information into a LIN (local interconnect network) bus message which passed via the clockspring to the instrument cluster in the LIN (local interconnect network) bus.
NOTE:
The control module in the RH (right-hand) steering wheel switch assembly also passes information from the speed control switches to the speed control module in the same way, but these are not related to instrument cluster operation and control.
DESCRIPTION
Instrument Cluster
The instrument cluster comprises a 12.3 inch Thin Film Transistor (TFT) with a multilayered virtual display. The cluster has a high level of graphic presentation and interactive functionality. These features give the driver advanced levels of control and set-up using interactive graphic menu features.
The instrument cluster combines a virtual representation of virtual analogue instruments, graphic information, digital information and warning signals. The cluster is linked via a LVDS cable, the MOST ring and the medium speed CAN (controller area network) bus to the TSD which provides selected information directly in the driver's view in addition to the instrument panel mounted TSD.
The TFT screen uses a specific type of field-effect transmitter made by depositing thin films of a semi-conductor active layer, as well as the dielectric layer and metallic contacts, over a supporting substrate. The display comprises an active matrix of a large number of individual light emitting picture elements (pixels). Each pixel incorporates its own transistor switch and is controlled by the application of positive and negative voltages across rows and columns. The transistors are made from a thin film of silicon deposited on a glass panel (hence TFT) and each transistor takes up only a small fraction of the area of its pixel. The remaining part of the silicone film is etched away to allow light from the pixel to pass through forming the display.
The instrument cluster screen displays at a resolution of 1280 X 480 pixels, at a cycle time of 30 frames per second and an aspect ratio of 8:3 (image width divided by the height), so it has clear definition and no visible delay in changing information.
The instrument cluster presents the information in 3 zones, but the information displayed in each zone can vary with the chosen mode and the required information to be displayed.
Standard Mode Display
In standard mode the:
LH (left-hand) Dial includes the following displays:
- Fuel gage
- Digital clock, ambient temperature or frost warning icon
- Information center with sub-displays for entertainment, phone and navigation
- Trip computer with sub-display for vehicle odometer, journey distance, average speed, average fuel consumption, instantaneous fuel consumption and distance to empty
- Engine temperature gage
- Warning indicators.
Center Dial includes the following displays:
- Speedometer
- Warning indicators.
RH (right-hand) Dial includes the following displays:
- Normally the tachometer
- Message center to display warnings and temporary alerts
- system control menus, selected using the joy pad on the RH (right-hand) steering wheel switch.
The 3 zones can display warning indicators at dedicated locations as shown the following illustration.
Warning Indicators
The general warning indicators (amber and red) are illuminated to alert the driver to a message in the message center. They are illuminated when a warning is required to be displayed, even if it is not currently being displayed due to being cycled with other messages. All warning messages are associated with a warning indicator colour according to their status. Some messages are associated with a no-color warning which means the message is displayed without one of the general warning lamps being illuminated.
When the ignition is off the instrument cluster TFT screen is blank. When the vehicle is unlocked, the instrument cluster, along with the TSD, begin a start-up routine which is not visible to the driver. The start-up routine includes acquiring data from vehicle systems. The display is configured once the start burton is pressed to either switch on the ignition or start the engine.
The instrument cluster displays the Jaguar 'leaper' badge before the main instrument graphics begin to be displayed and the instrument cluster performs a series of 'pre-drive' checks. The instrument cluster displays the standard 3 dial display of speedometer, tachometer and fuel/temperature gage. The dials, although entirely 'virtual' give a 3-dimensional impression of being physical dials with shadows and highlights added by the TFT screen.
The needles on the dials are also virtual and sweep around the speedometer and tachometer dials in the same manner as a 'conventional' mechanical needle. As the needle approaches a number on the dial, that number and the number preceding and following it become more prominent by brightening the display in that area of the TFT. This feature can be selected on or off using the display settings menu.
The instrument cluster can determine what information to display, when to display it and where on the display it will be shown. This is governed by preset display properties. The system versatility allows the instrument cluster to display information or hide it from view when its is not required.
Dynamic Mode Display
A dynamic mode is available by pressing the dynamic mode button in the floor console. When selected, this mode modifies the instrument cluster display only the components required for performance driving. A chequered flag icon is displayed in the tachometer to signify that dynamic mode is active and the display is illuminated in a red color.
If winter mode is selected by pressing the appropriate button on the floor console a message is displayed in the tachometer area, with a combined car and snow flake image with the words 'Winter Mode Confirmed' displayed. The change to this mode is confirmed by the instrument cluster being illuminated in a blue highlighting color and a winter mode icon is displayed in the tachometer area.
The instrument cluster can be easily changed by the driver to display either imperial (miles) or metric (km) units for the trip computer, speedometer and ambient temperature. This is configured during vehicle production to meet legislative and market requirements, but the driver can change certain unit displays using the instrument cluster menus.
Instrument Cluster Menu
The driver can use the 'joy pad' on the RH (right-hand) steering wheel switch assembly to navigate through a series of menu-driven features. The menu's are displayed in the RH (right-hand) side of the instrument cluster and override the tachometer display. If another function of higher priority is required to be displayed, then the menu display will also be overridden. The menu will be displayed until the driver closes the menu display.
When the driver uses the joy pad on the RH (right-hand) steering wheel switch assembly the menu appears as vertical stack of 6 rows of menu selections as follows:
- Main Menu
- Show Warnings (OK)
- Vehicle Set-up
- Trip Computer
- Display Settings
- Service Menu.
Most menu levels are contained on one page, however, for lists with more than 6 sub-items additional up/down arrows are positioned adjacent to the menu to signify there are additional menu items to display. The menu items and sun-menu items will not obscure any active warnings in the instrument cluster.
Dependent on vehicle specification, if a feature is not present on the vehicle, it will not be shown in any of the menus.
To exit the menu navigate the cursor to the 'back' arrow on the LH (left-hand) side of the Main Menu line. The menu will be removed and replaced with the tachometer or the message center, dependant on priority.
The Service Menu allows access to the following information:
- Vehicle Identification Number (VIN)
- Oil level display (not dynamic)
- Auto High Beam (AHB) sensitivity.
The AHB sensitivity is only available for NAS markets as a test option.
Additional Instrument Cluster Features
A speaker is mounted on the top of the instrument cluster casing. The speaker generates audible warnings and is controlled by a sound generator within the instrument cluster. The speaker cannot be replaced separately.
On each side of the TFT screen are 4 small apertures, 2 each side. The upper apertures on each side are ambient light sensors. The sensors are used to adjust the cluster illumination in response to the prevailing ambient light conditions. The instrument cluster also has high output LED (light emitting diode) backlighting and a smoked glass screen which helps prevent washout by reducing the amount of sunlight that can reach the screen directly. The TFT screen also incorporates an anti-glare coating.
The lower apertures contain LED (light emitting diode) status warning indicators. The LH (left-hand)
LED (light emitting diode) is the primary SRS (supplemental restraint system) warning indicator. A secondary SRS (supplemental restraint system) warning indicator is located within the TFT screen and is only used in case of failure of the primary warning indicator for legislation requirements.
The instrument cluster is integrated into the vehicle start authorization process as it includes encoded data exchange information as part of the distributed start authorization strategy. The cluster also controls the ground switching of the electric steering column lock.
Cooling Fan
An electric cooling fan is located outboard of the steering column, behind the instrument panel. The fan is attached to a bracket which in turn is attached to the instrument panel structure.
The fan has a filtered air intake and draws air from below the instrument panel. Plastic ducting is routed from the fan to the rear of the instrument cluster. A rectangular port in the instrument cluster distributes the cooling air around the rear of the TFT screen. The ducting from the instrument cluster is also routed to the rear of the TSD to provide cooling for the TSD in high ambient temperatures.
NOTE:
Vehicles fitted with a dual-view TSD have an integral fan within the TSD, in addition to the cooling fan for the cluster. Single view TSD units have no integral fan and rely solely on the cooling from the cluster fan.
Right Hand (RH) steering wheel mounted switch assembly
The instrument cluster menus are navigated and items selected using the joypad control. The joy pad control is a 2-axis switch with a central button (OK).
Pressing any of the joypad controls activates the menu display in the instrument cluster.
The up and down arrows can be used to navigate through the menu list, with the selected menu being highlighted. If the selected menu has a sub-list, the right arrow is used to display and view the sub-list. Pressing the left arrow will close the sub-list and return to the main menu. To select an menu, press the OK button and the selected menu will be displayed in the instrument cluster.
If the menu is activated and no further selections are made using the joy pad within 10 seconds, the menu will time-out and the menu will be removed from the instrument cluster display. Once the joy pad has been used to select a menu, the time-out period is extended to 30 seconds.
To exit the menu's, select the top menu 'Main Menu' and press OK to close the menu display.