Intrusion Transceiver Module (ITM) With Ultrasonic Intrusion Sensors

The ITM with the integrated Anti-Tilt Sensor communicates with the siren module and the ultrasonic intrusion sensors over dedicated serial bus circuits.

The ITM continuously monitors inputs from the five ultrasonic transducers as well as inputs from the BCM and the siren module. The ITM energizes the intrusion sensors when the system is armed, then monitors inputs from the sensors related to motion and tilt detection as well as detecting problems with the sensors or sensor circuits. If an object is moving in the interior, a detection circuit in the intrusion sensor senses this movement through the modulation of the returning microwave signals that occurs due to the Doppler effect.

If movement is detected while the VTA is armed, the ITM sends an electronic status message to the BCM over the CAN data bus to flash the exterior lighting, and sends an electronic message to the siren module over a dedicated serial bus line to sound the siren. When the BCM detects a breach in the perimeter protection through a hard wired door, swing gate or hood ajar switch input, it sends an electronic message to the ITM and the ITM sends an electronic message to the siren over a dedicated serial bus line to sound the siren.

The ITM also monitors inputs from the siren module for siren battery or siren input/output circuit tamper alerts, and for siren battery condition alerts, then sets active and stored Diagnostic Trouble Codes (DTC) for any monitored system faults it detects.

The Ultrasonic Intrusion Sensors operate only when they are energized by the ITM. The sensors transmit ultrasonic signals throughout the vehicle cabin through a transducer. The sensor then listens to the returned ultrasonic signals as they bounce off of objects in the vehicle interior and provide input signals to the ITM. If an object is moving in the interior, a detection circuit in the ITM senses this movement through the modulation of the returning signals that occur due to the Doppler effect. The ITM monitors the current draw of the sensor circuits to determine the condition of the sensors and, if the draw is too high or too low, it will store a DTC for any fault that is detected.

Inputs

• Commanded ignition switch status from the BCM (CAN-IHS)
• Motion detection disable request from the BCM (CAN-IHS)
• VTA status from the BCM (CAN-IHS)
• System voltage from the BCM (CAN-IHS)
• Vehicle configuration parameter from the BCM (CAN-IHS)
• ITM ECU configuration from the BCM (CAN-IHS)
• "Heart Beat" command responses from the intrusion sensors
• Motion detection output from the intrusion sensors
• Tilt detection from the integrated anti-tilt sensor
• Siren battery condition from the siren module

Outputs

• ITM alarm indicator request to the BCM (CAN-IHS)
• ITM motion detection disabled to the BCM(CAN-IHS)
• ITM status and alarm requests to the BCM (CAN-IHS)
• "Heart Beat" command signals to the intrusion sensors
• Siren battery management to the siren module