Electrical (Perimetric Sensing): Description and operation

Perimetric Sensing

Perimetric sensing is invoked by the CCU to monitor entry to the vehicle after the alarm has been set. The panel open switches on the driver’s door, passenger door(s), tail door, bonnet and roof (3 door only) are all monitored by the CCU.

If a panel is opened after the alarm has been set, the alarm will be triggered. The horn or BBUS will sound and the hazard warning lights will operate. On 3 door models, if the roof is off when the alarm is armed, further operation of the roof off switch will not trigger the alarm.

Volumetric Sensing

The volumetric sensor is located in a central position on the roof panel, behind the headlining. The volumetric sensor monitors movement inside the vehicle to detect any possible intrusion. The vehicle can be armed with the volumetric sensor disabled to avoid accidental triggering of the alarm if a pet is in the vehicle for instance. The volumetric sensor is also inoperative if the CCU senses that a panel has been left open, with the exception of the bonnet.

A fifteen second delay is initiated after arming of the alarm before signals from the volumetric sensor are interpreted as an intrusion. This precaution is included in the CCU software to avoid accidental or nuisance triggering of the alarm.

If the alarm has been triggered, the CCU will ignore further volumetric sensor signals for the duration of the alarm sounding. The CCU will delay volumetric sensing for a further 15 seconds after the alarm has stopped sounding, unless ten triggers have been sensed by the volumetric sensor since the alarm was last armed.

The volumetric gain setting is controlled by the VIN stored in the CCU. The VIN informs the CCU of the vehicle body and roof type to avoid under or over sensitivity.

If battery supply voltage falls to below 9 Volts, the CCU will ignore inputs from the volumetric sensor.

Alarm - Key Operation

Arming and disarming using the vehicle key in the driver’s door key barrel will be ignored if the CCU senses that the ignition is on. In certain markets the alarm system is programmed not to arm under any circumstances, in these cases key operation will only operate the door locking facility as described in Key Locking/Unlocking.

NOTE: Using the vehicle key in the driver’s door key barrel will not enable the volumetric sensing.

Key Arm

The vehicle alarm can be fully armed by turning the top of the key to the rear of the vehicle once with all panels closed. The Vehicle will be CDL locked, the hazard warning lights will flash three times. The alarm LED will fast flash for ten seconds and then change to slow flash. Perimetric sensing, engine immobilisation and starter relay disable will be activated.

The vehicle alarm can also be fully armed by turning the top of the key to the rear of the vehicle a second time, within one second of the first turn, with all the panels closed. The vehicle will be superlocked, the hazard warning lights will flash three times. The alarm LED will fast flash for ten seconds and then change to slow flash. Perimetric sensing, engine immobilisation and starter relay disable will be activated.