Road Traffic Information (RTI) System
Road Traffic Information (RTI) System
System Overview
The main role of the RTI system (Road and Traffic Information) is to manage the functions for:
- the GPS antenna
- 5 inch. LCD display screen (only used in systems with a CD changer system)
- 6.5 inch. wide screen LCD display screen (only used in systems with a DVD system)
- Steering wheel buttons
- TV receiver (accessory)
- The remote control (accessory)
- The CD changer (not used for DVD systems)
- DVD player (not use for the CD system).
There are two models of the RTI system, one old and one new version.
The older system has two units, the RTI control unit and the CD changer. In the new system the CD changer has been replaced by a DVD player which is integrated with the RTI control module.
The control module is located in the left section of the cargo compartment.
CDs cannot be played in the RTI system. This is because the system is not compatible with these types of disc.
The RTI system communicates partly with components which are directly connected and partly with other control modules and components via serial communication and Control area network (CAN).
The control module checks activations and input and output signals using an integrated diagnostic system A diagnostic trouble code (DTC) is stored if the control module detects a fault.
Diagnostic trouble codes (DTC) are stored in the control module memory. The data can be read off using the diagnostic tool.
A simple way to check that the RTI components are both powered and grounded is to try to insert or remove a CD or DVD. The RTI system is powered and grounded if the disc can be inserted and removed. If this is not functioning, check the power supply and ground for the RTI system.
The RTI system has an internal communication system, Melbus. Communication is between the RTI unit, the TV receiver, the CD changer and the audio module.
Melbus communication consists of three different signals:
- MSCK, clock signal
- MDATA, data signal which transmits information
- MBUSY, indicates whether the data signal is engaged or not.
Signals
The above table summarizes input and output signals to and from the RTI control module. The signal types are divided into directly connected signals, serial communication and Control area network (CAN) communication. The illustration displays the same information with the Volvo part numbers.
Design
The GPS Antenna
The data transmitted from the GPS antenna to the RTI control module consists of signals received from GPS satellites.
There is a signal booster (antenna amplifier) integrated in the GPS antenna. The signal is strengthened before it is transmitted to the GPS receiver which is integrated in the RTI unit. The GPS also adapts the impedance of the signal.
The RTI system and the GPS antenna require contact with at least three satellites to be able to calculate the position of the car. The RTI system can communicate with up to eight satellites at the same time.
The position calculated from the GPS satellites is accurate to within ± 30 meters.
View the GPS information under system settings to check how many satellites are available.
The power supply is from the RTI control module. The power supply uses the same high frequency wiring as the GPS information that is sent to the RTI unit.
The GPS antenna is located in the parcel shelf.
NOTE: If there is no GPS signal, the signal should be checked outside. The signal may be blocked if the car is indoors. Large objects on the parcel shelf or tinted rear windshields may also be the cause.
TV receiver
The role of the TV receiver is to manage the incoming TV signals from local TV transmitters.
There are three models of the TV receiver:
- One for Europe (PAL)
- One for U.S.A. (NTSC), only applies to the S80 Executive
- One for Japan (NTSC).
The European TV receiver can handle three different PAL systems. The menu system on the TV receiver is used to change the PAL system settings.
The TV receiver sends the received TV signals on a serial bus (Melbus) to the RTI system. The RTI system handles the incoming signals and sends them to the display screen.
The TV receiver transmits the TV sound on a serial bus (Melbus) to the audio module via the RTI unit.
Station settings, color, TV picture size and the screen contrast are set using the audio module or the remote control.
The TV receiver is located in the left section of the cargo compartment.
RTI control module
The role of the RTI control module is to calculate the position of the car based on the signals it receives from the GPS antenna, the speed signal from the central electronic module, the gear position and the gyro. The RTI system then works out a route for the selected destination.
There are two models of the RTI system, one old and one new version.
The older system has two units, the RTI control unit and the CD changer. In the new system the CD changer has been replaced by a DVD player which is integrated with the RTI control module.
There is an integrated three dimensional piezo electrical gyro in the RTI control module. This manages data about the movements of the car, such as whether any turnings are made.
Data transmitted on the CAN to the RTI unit from different nodes is:
- vehicle speed
- wheel rotation counter
- back-up (reverse) gear position
- signals from the steering wheel controls
- radio mute
- background lighting.
Gyro and wheel rotation counters are used to calculate the position of the car for shorter periods, if communication with the GPS satellites is lost in a tunnel for example or to assist when there is no GPS signal.
Used in conjunction with map matching, GPS navigation, the gyro and the speed signal, the position can be calculated to an accuracy of ± 10 meters from the position indicated on the screen.
The traffic message channel (TMC) receiver is integrated in the RTI unit. TMC is a standardized code system for traffic messages such as road works. The Japanese equivalent is called FM multiplex.
There is no traffic information system in the USA.
The TMC antenna is located in the right-hand section of the rear bumper.
The control module is located on the left-hand side of the cargo compartment.
The RTI (road traffic information) control module can be diagnosed.
Display
There are two sizes of display screen. There is a 6.5 inch. wide screen LCD screen and a 5 inch. LCD screen.
All signal information to the screen is from the RTI control module.
The screen has an infra red eye above it which is used for communication with the remote control.
The menu system for the screen can be controlled using the RTI buttons on the reverse of the steering wheel or using the remote control.
The screen is positioned in the middle of the dashboard.
CD changer
A six disc CD changer is used together with the RTI control module on the older RTI system.
This unit only handles CD discs with map information, not music CDs.
The discs contain information about road networks, streets, voice guiding and the software required for the system to function. The CD changer communicates with the RTI unit on serial buses (Melbus).
Remote control
There is a dedicated remote control for the RTI unit. The function of the remote control is the same as the steering wheel buttons.
There is also a separate remote control for the TV receiver which can be used to store and change TV stations, the color, the size of the picture and the contrast on the screen.
Function
GPS Navigation
RTI with integrated DVD
RTI with CD changer
The GPS antenna (16/47) receives signals from a minimum of three and a maximum of eight GPS satellites. These signals are then sent on to the GPS receiver in the RTI control module (16/45).
The position of the car is calculated and a route is displayed for the selected destination.
Data for voice guiding for the selected route is transmitted on the serial bus (Melbus) between the RTI control module and the audio module (16/1).
In order for the RTI system to select a route, a DVD (16/45) or CD (16/48) must be available with the road network. For CD changer systems the data is transmitted on a serial bus (Melbus) to the RTI.
Data about speed, the wheel rotation counter and parking brake is sent using CAN communication from the central electronic module (4/56), ABS (4/16) and driver information module DIM (5/1).
Data is sent to the display screen (16/46) from the RTI control module on serial buses.
Commands from the remote control are sent from the display screen (16/46) to the RTI unit (16/45) on a serial bus (remocon signal).
The menu is accessed and used via the buttons on the reverse of the steering wheel. Data is sent from the steering wheel module (3/130) to the RTI unit (16/45) via the Control area network (CAN). There are three steering wheel buttons which are used to control the menu on the screen. There is a four-way switch on which each part of the switch moves the cursor upwards, downwards, to the left or to the right. There is an ENTER button and a BACK button.
When a new GPS antenna is installed for the RTI system, it may take up to 15 minutes before the GPS receiver has the correct information.
Traffic message channel (TMC) reception
The role of the TMC receiver is to receive traffic information on the FM wavelength. The Japanese system is called FM multiplex.
The TMC receiver is integrated in the RTI system and is connected to the antenna system for the FM radio.
There is no traffic information system in the USA.
The TMC data signal is received by the TMC/FM multiplex antenna (16/68) which is located in the rear bumper. The signal is boosted by the antenna amplifier (16/67) before it is sent to the RTI unit (16/45). This data is displayed on the screen (16/46).
TV reception
The TV antenna pattern on the rear windshield (16/54 for the V70/V70XC, 16/9 and S60/S80) receives signals from the TV network. These signals are boosted in the TV antenna amplifier (16/71) which sends the signals to the TV receiver (16/36). The signals are sent on to the RTI unit (16/45) on a serial bus (Melbus). The RTI unit send the signals containing sound information to the audio module (16/1) on a series bus (Melbus) and signals containing picture information to the display screen (16/46).
When the vehicle speed exceeds 7 km/h the RTI changes to navigation automatically.
The SOURCE button on the audio module (16/1) or on the remote control is used to set the TV stations.
RTI diagnostic functions
General
The RTI control module has a built-in diagnostic system, the Volvo on-board diagnostic (OBD) system, which continuously monitors itself and the input and output signals.
Diagnostic trouble codes (DTCs)
A diagnostic trouble code (DTC) is stored if the RTI detects a fault. A fault which is detected in the latest driving cycle is defined as permanent. Other detected faults are defined as intermittent.
Reading and erasing diagnostic trouble codes (DTCs)
Stored diagnostic trouble codes (DTCs) can be read off and erased using this function.
Diagnostic trouble codes (DTCs) can only be erased when all diagnostic trouble codes (DTCs) have been read at least once.
Reading off the control module identification
VADIS/VIDA identifies the control modules by reading off a number of codes of RTI memory.
The codes contains information about the RTI control module's:
- hardware P/N (control modules without software)
- hardware serial number (control modules without software)
- software P/N
- P/N diagnostic software.
Downloading Software and Replacing The Control Module
New software can be downloaded into the RTI control module. When ordering software, the hardware and the software in the car is compared to the Volvo central database. If the comparison is OK the software is downloaded to the control module.
If the comparison between the car and Volvo central database does not correspond, the database is updated with the configuration of the car. New software is downloaded after the update is complete.
All other software required for the RTI system to work is on the CDs or DVDs.
The following applies when downloading new software versions:
- The early version CD for structure weeks 199815 to 200019 only functions in the control modules from the same structure weeks
- New version CDs from structure week 200020 onwards function in all RTI (road traffic information) systems with CD changers
- DVDs, irrespective of version, function in all RTI (road traffic information) systems with DVD players.