ALARM SYSTEM

The alarm sytem is one of the devices that contributes in protecting the vehicle.

AIM

The alarm system has the function of protecting the vehicle from unauthorized access, detecting and signalling attempts at intrusion with visual/acoustic warnings.

GENERAL DESCRIPTION

The alarm system carries out perimeter and volumetric surveillance, surveillance against the vehicle being tilted and surveillance of the supply leads and ignition.

The switching on of the alarm system is shown by the direction indicators coming on constantly and a beep from the siren in conjunction with the direction indicators coming on.

At this point a deterrent warning light/LED located in each door panel flashes intermittently to indicate the surveillance state.

The alarm system is homologated in accordance with directive 95/56/CE and conforms with the requirements of European insurance companies and their associated technical centres.

DESCRIPTION OF THE SYSTEM COMPONENTS

The basic alarm system components are:

• Body Computer Node (NBC)
• Alarm siren
• Volumetric sensors
• Tilt sensor
• Perimeter sensors (door, boot lid and bonnet switches)
• Transmitter in key-remote control or in CID

Body Computer Node (NBC)

The NBC is also dedicated to the management of the alarm system.

Several functions are also implemented that make it possible to co-ordinate and manage the alarm system sending and receiving commands from the external modules on the A-BUS serial line.

Alarm siren

The alarm system is equipped with a self-supplied siren.

The siren carries out two functions:

• 1. Acoustically signalling an attempt to break in and damage the vehicle.
• 2. Emitting the system beep signalling noises.

Specifcations

The main specifications of the siren are:

• sealed casing (IP66)
• NiMH green batteries for independent supply if the main vehicle battery supply leads are interrupted
• dialogue with the NBC and other alarm system components on the serial line
• autodiagnostic function
• maximum permitted current consumption:
• Sound power (when supplied): 107 - 118 dBA/2 metres

The siren is equipped with a 4-way sealed connection designed to receive a sealed female holder connector with the pin out described in the table:

Operating limits:

• Voltage range: 9 - 16 V. Below the minimum voltage the siren receives a supply from its own internal battery.
• Temperature range: - 40° / + 85°C (if connected to the main supply); -20° / + 85°C (if receiving its own supply)

Serial connection

The siren is connected to the A-BUS serial line, therefore it is connected with the NBC and all the sensors/actuators for the vehicle protection sub-systems.

This connection allow the exchange of commands between the two units (siren and NBC). If this connection fails, the possibility of communication is lost.

In addition, if the serial line is overloaded, the siren functions take priority over other communication on the line.

If the main supply leads are cut and the internal batteries are charged, the siren can:

• with the +30 cut, communicate in two directions
• with the earth cut, receive, but not reply (this produces alarm signals)

If the batteries are run down, in both of the above mentioned cases, the siren reverts to WAREHOUSE mode and when the supply is restored later on a hardware reset is produced.

Hardware reset

A hardware reset is a temporary state that allows the siren to go from the WAREHOUSE condition to the REST condition.

A hardware reset cannot be carried out from the outside.

Device operating states

There are 5 different operating states for the siren:

• WAREHOUSE
• REST
• SURVEILLANCE
• ALARM
• DIAGNOSIS

WAREHOUSE

This is the state that the component in supplied in.

It is the state the component is in when the main supply and that from the internal batteries starts to fail.

This mode represents a protective state in addition to the starting point for the generation of the hardware reset.

We come to the WAREHOUSE state:

• from the REST state (if the outside supply fails)
• from the ALARM state (at the end of the signals for cutting the supply leads)

REST

This is the state the component is fitted on the vehicle in, connected to the main supply, if it is not activated by the reception of a switching on signal.

In this condition it is possible to disconnect the battery supply leads to carry out servicing operations without causing the siren to produce acoustic signals.

During the rest state the siren is in the minimum consumption condition (see table).

If there is a fall in voltage ( < 7V), the siren waits fro 16 secs after which it enters the WAREHOUSE mode.

In this operating state, and if there is a +15 signal, the batteries inside the siren can be recharged. The command is sent by the NBC to the siren and it is asked to manage the recharging strategy.

the recharging ends when:

• there is no + 15 signal
• the siren receives a command to switch on
• 5 secs after the key-on

It is possible to move from the REST state to the following states:

• SURVEILLANCE: using the control for switching the siren on
• ALARM: if the acoustic warning siren cycle is activated
• WAREHOUSE: following a decrease in the supply
• DIAGNOSIS: following a specific command

SURVEILLANCE

This siren operating state corresponds to the user switching the vehicle alarm system on.

The siren is set in this operating mode by the NBC which, having received the command to switch the alarm system on, in turn, sends the command to switch the siren on.

The command sent by the NBC to switch the siren on is accompanied by a random 2 byte code. This code is memorized by the siren. When there is a request to switch the alarm system off, the NBC should send the command to the code which should correspond with the one memorized by the siren. In this way the system is protected against possible attempts at intrusion with the aim of deactivating the siren.

In this configuration the component needs to move to the alarm state following the verification of predetermined events.

These events are:

• a fall in the main supply voltage: if the battery voltage goes below 3 V, the siren sets of the alarm cycles.
• Cutting of +30 lead: in this case the siren starts the acoustic alarm cycle until normal supply conditions are restored or the alarm is switched off. The maximum number of alarm cycles implemented by the siren corresponds to the figure transmitted by the NBC at the time it is switched on.
• Cutting the earth lead: the siren does not immediately set off the alarm cycle, but waits for the NBC to make itself available. In effect, in normal operating conditions, to check the condition of the connection, the NBC sends the siren a signal known as a heart-beat approximately every 500 ms. If the siren does not receive this signal for a maximum time of 0.5 secs, the alarm cycles commence. When the alarm cycles are over, the siren goes into the WAREHOUSE state. Given that the NBC is not capable of transmitting the heart-beat signal below certain battery voltage values, if the emission of the signal is interrupted, the siren checks that the battery voltage is above 7.5 V and, if it is below this, the alarm acoustic signals are inhibited.
• Cutting the serial communication line cable: the reaction logic is the same following the cutting of the earth lead. The only difference is that, at the end of the alarm cycles, the siren moves to the REST state.

It is possible to move from the SURVEILLANCE state to the following states:

• ALARM
• REST: if the command to switch off is received.
• DIAGNOSIS: following a specific command.

ALARM

If the alarm system detects an attempt to break into the vehicle, tamper with it or enter it, it configures the siren in the ALARM state

In this state the siren produces acoustic signals.

The activation of the acoustic alarm is always managed and activated by the NBC and not by the siren.

The signalling consists of a succession of alarm cycles.

An alarm cycle is defined as the issue of a sound (managed by the NBC) lasting 26 secs (max 29 secs for cable cutting) followed by a 5 second pause, in accordance with the regulations laid down in directive 95/56/CE.

The management of the type, number and duration of alarm cycles, in accordance with the operating mode, is entrusted to the NBC with the details given in the table below.

The move to the siren alarm state also implies sending the NBC a particular command indicating the reason for triggering the alarm.

It is possible to move from the ALARM state to the following states:

• SURVEILLANCE: at the end of an alarm cycle requested by the NBC
• REST: if the command to switch off is received or at the end of alarm cycles resulting from cable cutting.
• DIAGNOSIS: at the end of alarm cycles resulting from supply cable cutting.

DIAGNOSIS

When it is switched on the alarm system sends the siren a request, via the serial line, to carry out an autodiagnosis on its sub-systems.

The siren should send a response command within 3 secs.

If it is not possible to carry out the autodiagnosis, the system uses the information received the previous time.

Volumetric sensors

The main purpose of the volumetric sensors is to detect an attempt to intrude into the passenger compartment using ultrasound.

A variation in the volume inside the passenger compartment, identified by the waves, produces a signal which is sent to the NBC which implements the appropriate alarm procedure.

The volumetric sensors are integrated in the Roof Node (NIM). It manages the software functions, houses the on/off button and operates the LED which is incorporated in the button and which warns about the implementation of the control.

The switching on/off of the sensor is controlled by the A-BUS serial line.

Specifcations

The volumetric sensor has a 4-way connector with the following pin out:

• 1 = Supply positive (+30)
• 2 = Negative (earth)
• 3 = +15
• 4 = Serial line (A-BUS)

Operating limits:

• Voltage range: 8 - 16 V.
• Temperature range: - 40° / + 85°C
• Wave emission frequency: 40 Khz
• Maximum permitted current consumption:

Device operating states

There are 4 different operating states for the siren:

• REST
• SURVEILLANCE
• ALARM
• DIAGNOSIS

REST

This is the state of the component, fitted on the vehicle, connected to the vehicle battery.

In the REST state the volumetric module should be in the minimum consumption conditions in order to reduce the battery current absorption.

In the REST state, with the alarm system switched off and the key-off, it is possible to manually exclude the volumetric protection by pressing the exclusion button in the courtesy light (NIM). The exclusion of this protection involves the sensors not being switched on.

This exclusion is shown by the LED in the NIM exclusion button flashing and involves sending the exclusion signal to the NBC via the serial line.

If more than 1 minute has elapsed since the key-off, a new key-on must be carried out in order to exclude the sensors.

The volumetric protection exclusion situation persists until the next command to switch off the alarm: from this time onwards the sensors can be activated once again.

It is possible to move from the REST state to the following states:

• SURVEILLANCE: using the control for switching the ultrasound on
• DIAGNOSIS: following a specific command

SURVEILLANCE

The volumetric sensors are in this configuration if the alarm system is switched on and they have not been excluded previously.

During the SURVEILLANCE stage, the sensors protect the passenger compartment, checking for the presence of moving bodies.

If an intrusion is detected, the NIM sends a signal to the NBC which produces a command for the alarm system to signal a theft attempt.

If the battery voltage is below 8.5 V for longer than 30 mins, this causes the volumetric sensor module to be switched off in order to safeguard the life of the battery and to be able to start up the engine later on.

It is possible to move from the SURVEILLANCE state to the following states:

• ALARM: as a result of the detection of an intrusion
• REST: following a switching off command

ALARM

This is the configuration the sensors are in if an intrusion is detected during the SURVEILLANCE state.

This situation is communicated to the NBC by sending an appropriate signal.

In order to prevent false alarms, these sensors have self-adaptation and temperature compensation functions to reduce their sensitivity to the variations in air density due to temperature and the type of fabrics used for the interior trims.

It is possible to move from the ALARM state to the following states:

• SURVEILLANCE: following adjustments after an intrusion
• REST: following a command to switch off the alarm

DIAGNOSIS

At the time the alarm system is switched on, the NBC requests the sensor module state by sending an appropriate command.

The sensors should respond to the autodiagnostic request within 4 secs.

The diagnostic request can only be carried out if the sensors are in the REST state.

If the sensors are not working they will not be activated and the cause will be stored in the diagnostic memory.

Tilt sensor

The main function of the tilt sensor is to detect a change in the angle of the vehicle and signal this to the NBC in order warn that the vehicle is being raised or an attempt is being made to steal part of it (e.g. the wheels).

The tilt sensor is incorporated in the NIM, from which it receives a supply. It is operated by the A-BUS line managed by the NBC which uses the NIM to house the tilt sensor.

The NIM also has the button for excluding the module and operates the LED which is incorporated in the button and which warns of the implementation of the control.

Specifcations

The volumetric sensor has a 4-way connector with the following pin out:

• 1 = Supply positive (+30)
• 2 = Negative (earth)
• 3 = +15
• 4 = Serial line (A-BUS)

Operating limits:

• Voltage range: 8 - 16 V. The nominal supply voltage is 13.5 V with an absorption = 3mA
• Temperature range: - 40° / + 85°C

Device operating states

The tilt sensor should detect and signal a variation in the vehicle geometry angle in relation to the longitudinal and transverse axes of the actual vehicle.

There are 4 different operating states for the siren:

• REST
• SURVEILLANCE
• ALARM
• DIAGNOSIS

REST

This is the state the tilt sensor is in when the alarm system is not switched on; no operation is activated in this stage.

In the REST state, with the alarm system switched off and the key-off, it is possible to manually exclude the tilt protection by pressing the exclusion button in the courtesy light (NIM). The exclusion of this protection involves the sensors not being switched on.

This exclusion is shown by the LED in the NIM exclusion button flashing and involves sending the exclusion signal to the NBC via the serial line.

If more than 1 minute has elapsed since the key-off, a new key-on must be carried out in order to exclude the sensors.

The tilt protection exclusion situation persists until the next command to switch off the alarm: from this time onwards the sensors can be activated once again.

SURVEILLANCE

The tilt sensors is in this configuration if the alarm system is switched on and it has not been excluded previously.

During this stage the sensor begins the check on the angular position of the vehicle at the two axes which ends 30 secs after it is switched on. This check is designed to create a reference position. No alarm is generated during this period.

The calculation of the angular references for the 2 axes is carried out through successive sampling.

The position calculated at the end of the 30 secs is memorized.

During the SURVEILLANCE stage the sensor should constantly monitor the angle of the vehicle, filter alterations due to slight swaying, parking near interference and wind conditions, sounding the alarm in the case of a theft attempt.

The reference calculated when the alarm system is switched on is zeroed when:

• the alarm is triggered.
• The difference between the angles is zeroed.
• 5 minutes elapse without detecting an alarm.
• Alarm due to temperature drift.

ALARM

The tilt sensor is able to produce an alarm condition when a change in angle in relation to the reference position memorized is detected as a result of a rotation around the longitudinal or transverse axis of the vehicle at a speed of 0.5°/min. In this condition the alarm is produced before a tilt of 3° is reached.

No alarm conditions should be created for rotation speeds of less than 0.5°/min.

The alarm signal is sent to the NBC via the A-BUS serial line.

DIAGNOSIS

At the time the alarm system is switched on, the NBC requests the sensor state by sending an appropriate command.

The sensor should respond to the autodiagnostic request within 3 secs.

The diagnostic request can only be carried out if the sensor is in the REST state or the SURVEILLANCE state.

If the sensor is not working it will not be activated and the cause will be stored in the diagnostic memory.

Perimeter sensors

These sensors are designed to detect unauthorized intrusion into the passenger compartment, the engine compartment and the luggage compartment.

Transmitter in key-remote control or CID

Both these devices are designed to make the authorized user in possession of them recognizable to the vehicle.

These devices allow the alarm/anti-theft system to be switched on and off.

SYSTEM STATES

There are eight different possible states for the alarm system:

• DEACTIVATED
• REST
• ON
• SURVEILLANCE
• ALARM
• OFF
• PROGRAMMING
• DIAGNOSIS

Deactivation

This is the state the alarm system finds itself in each time the CODE system or the Passive Entry system recognizes an enabled key or CID.

The alarm system is not switched off if the vehicle is released using the mechanical insert.

This results in the anti-theft system being switched off.

When the alarm system is deactivated it does not respond to the commands from the receiver or the Passive Entry system.

It is possible to move from the deactivated state to the REST state by turning the key to key-off.

If it is not possible to unlock the vehicle using the remote control or using the Passive Entry system (as a result of electro-magnetic interference or if the batteries are run down), access to the vehicle can be gained using the mechanical insert: the alarm system is activated when the driver's door is opened and the siren starts to sound.

To interrupt the emission of the sound and deactivate the alarm, simply activate the instrument panel as follows:

• insert the key in the ignition and turn it to the ON position (for systems with a mechanical key).
• Activate the instrument panel using the control button, if necessary placing the CID in the Garage position.

Rest

It is the basic state the alarm system finds itself in.

It is possible to move from the REST position to the following states:

• DIAGNOSIS: activated by connecting the Examiner to the NBC.
• SURVEILLANCE: when you wish to protect the vehicle through an insertion command.
• DEACTIVATED: when an enabled key or CID is recognized by the CODE/Passive Entry system.

In the REST condition, the NBC always controls the +15 which, if fitted, prevents the move to SURVEILLANCE and, above all, to ALARM.

In the REST condition it is possible to exclude the volumetric and tilt sensors within 1 minute of the key-off by pressing the relevant buttons in the courtesy light trim.

Switching on

Switching on is the operation that allows the alarm to move from the REST condition to the SURVEILLANCE state.

This operation is always inhibited if there is a +15.

SWITCHING ON the alarm system takes place the moment the doors are locked (using the remote control or through the Passive Entry system) and is signalled by the direction indicators coming on synchronized with the siren.

When the NBC receives the command (remote control, Passive Entry) it activates the alarm SWITCHING ON procedure as follows:

SIGNALLING OF SWITCHING ON IN PROGRESS. The operating mode is identified. The diagnosis of the alarm system modules is activated. The visual and acoustic signals for the time of SWITCHING ON are activated.

SYSTEM DIAGNOSIS. The plausibility of the door switches (2 or 4), the boot switch and the bonnet switch are checked and, if one of these entry points is found NOT to be closed, this entry point is excluded from the surveillance.

SENSOR STATE CHECK. If the siren is NOT OK after a maximum of 3 secs, the system causes the direction indicators to flash twice. After a maximum of 4 seconds after the system has been SWITCHED ON, the NBC receives the OK/NOT OK information from the volumetric sensors module and the tilt sensor. (see signalling modes in the next point). If the results on the state of these modules do not arrive within 4 seconds, then the respective module is declared non operational signalling the alarm sytem failure.

DIAGNOSTIC INFORMATION DISPLAY. The signalling of faults at the time of SWITCHING ON takes place via: 1 warning beep 4 seconds after the central locking/alarm on command. The signalling of the type of problem through the deterrent LED takes place in the following ways: A) flashing at 8 Hz for 2.5 seconds for volumetric failures. B) LED on constantly for 10 seconds for a siren failure or tilt sensor failure. Obviously, the system component found to be faulty will not be switched on.

MODULE SWITCHING ON: after the responses to the diagnosis are received, the operating modules, excluding the siren, are switched on

SIREN SWITCHING ON. If the siren is working properly, the management of the HEART-BEAT on the A-BUS serial line is activated, in other words a signal that is exchanged every 500 msecs. between the NBC and the siren to constantly check the condition of the communication line.

SWITCHING ON ENDED: the alarm system declares the SWITCHING ON stage over. Lastly, the deterrent warning light is controlled by the central locking system.

If a command to unlock the doors (corresponding to the SWITCHING OFF of the alarm sytem) is received during the SWITCHGING ON stage, the procedure is interrupted and there is a move to the SWITCHING OFF stage.

If visual and acoustic signals are in progress, they should be interrupted to implement the SWITCHING OFF signals.

Automatic switching on

This operation allows the alarm system to move from the REST state to the SURVEILLANCE state in an automatic, timed fashion.

There are two self-switching on modes: 1. From key-off 2. PASSIVE mode (from the last door).

1. From key-off

• the key-off is detected.
• the self-switching on counter begins counting.
• The counter reaches the "SELF-SWITCHING ON TIME" value.
• The NBC checks whether a valid transponder/CID is present.
• If there is no valid transponder, the self-switching on takes place irrespective of the door status.

2. PASSIVE mode (from last door):

• the key-off is detected.
• The first self-switching on counter starts counting (fixed time of 2 mins). If an open/closed transition takes place, within 2 minutes, at the driver's door or at the last door, boot or bonnet, a second counter starts counting
• The second counter reaches the "SELF-SWITCHING ON TIME" value.
• The NBC checks whether a valid transponder/CID is present.
• If there is no valid transponder, the self-switching on starts.

For both modes described, during the self-switching on cycle, the system should constantly check that there is no +15. If the +15 signal returns with a valid, recognized transponder/CID, then the procedure should be interrupted.

During the self-switching on stage the system diagnosis takes place in the same way as during the normal switching on stage.

The central locking is not activated during the self-switching on stage.

Switching on again

The operation of switching on again allows the sytem to move automatically from the REST stage to the SURVEILLANCE stage when, after an authorized switching off, the doors/boot/bonnet are not found to be open.

The procedure for switching on again is as follows:

• the alarm system is switched off.
• The switching on again counter begins counting.
• If a closed/open transition is detected at any of the driver's doors or the bonnet or the boot then the switching on again is cancelled.
• The counter reaches the "SELF-SWITCHING ON TIME" value.
• The alarm is switched on taking into account any system exclusions (volumetric protection, siren,...) made at the last switching on.

Surveillance

During the surveillance stage, the NBC reads all the signals/commands on the A-BUS operating the siren, via the A-BUS, if these signals/commands involve its activation.

The move to the alarm state is activated if the NBC verifies one or more of the following conditions:

• the presence of a +15 signal without a prior switching off command.
• Change of state for inputs coming from the doors, boot and bonnet (intrusion attempt).
• Command at the A-BUS for the external modules such as the ultrasound sensors, tilt sensor or from the siren (for cable cutting).

If the NBC detects a battery voltage of less than 8.5 V for longer than 30 minutes, then it switches off the external modules in order to safeguard the life of the battery and allow the engine to be started up later on.

If the user makes their intention to open the boot known (through the button on the remote control or by using the handle directly) and the system is in the SURVEILLANCE state, the NBC disables the volumetric/tilt external modules, disables the boot from the perimeter protection (with the doors and bonnet lid perimeter protection remaining activated) and activates the signalling through the blinkers.

If, however, within 1 second of the command (from the remote control), the boot switch does not change status, the system switches the protection back on again. This timing makes it possible to ensure the protection of the vehicle even with the boot/rearscreen entry point faulty. If, on the other hand, the boot/rearscreen is left open and then the alarm is switched on, the volumetric/tilt protection is switched on.

Alarm

If one of the sensors involved in the surveillance identifies an irregular situation (attempted or actual intrusion or theft of the vehicle), the alarm sytem moves to the ALARM state, activating the siren and blinkers.

If an alarm cause is detected during the surveillance stage, the NBC should implement the appropriate number of alarm cycles (visual+acoustic).

At the end of the maximum number of cycles (visual+acoustic), if further alarm signals are needed, they are only produced through the blinkers (flashing of the direction indicators).

If the NBC detects another alarm cause during an alarm cycle it ignores it. In effect, the NBC is only enabled to receive new alarm causes at the end of the alarm cycle.

The system is required, for diagnostic purposes, to keep track of the alarm causes recognized by the NBC.

The NBC memorizes the last 10 alarm causes, associating the cause and alarm system state at the time the system wash switched on with each of the causes.

It is possible to move from the ALARM state to the following states:

• REST: with a switching off command or through the recognition by the CODE system at the key-on of an enabled key or recognition by the Passive Entry system.
• SURVEILLANCE: when the alarm cycles set off are ended.

Switching off

The system can be switched off in both the SURVEILLANCE and ALARM states

It is carried out by the remote control or the Passive Entry system; the NBC commands the switching off of the alarm system the moment the doors are unlocked.

At the time of SWITCHING OFF, the NBC interrupts the perimeter protection and, if present, al the counter-measures activated.

The SWITCHING OFF controls the activation of the visual + acoustic signals.

The SWITCHING OFF command is also accepted if there is a +15 signal.

The alarm system can also be switched off in the following ways:

• by turning an enabled key to the ON position
• through the detection of a valid CID in the passenger compartment or in the GARAGE position (this last operation is necessary, for example, when the CID is run down, the customer opens the driver's door using the pawl and the alarm is consequently activated: by placing the CID in the GARAGE position the alarm can be deactivated).

At the first key-on after the SWITCHING OFF, the NBC commands the display of an alarms that have taken place, by means of a series of messages shown on the panel display.

Programming

The configuration of the alarm system installed on the vehicle can be programmed at the end of the line.

This configuration can be read, but not modified, by the diagnostic equipment which will adapt its diagnostic procedures depending on the configuration present.

Diagnosis

No diagnostic checks are required for the perimeter protection switches.

The NBC should carry out the diagnosis for the operation of the serial line connected to the siren and to the external modules.

The diagnosis of the external modules is entrusted to the functions that manage them.

The diagnostic information obtained at the time when the alarm system is switched on should be memorized to guarantee help for the system.

If an external module is recognized as not functioning, it is excluded for the entire surveillance cycle.

The next time the system is switched on, the diagnostic check is carried out again on the modules which should be reactivated if they are recognized as working.