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Emergency Alarm Function - GF82.25-S-2011TRA

Model 447 

with code ZK2 (Taxi version with emergency alarm system) 

Model 447 

with code ZM7 (Rental vehicle package with emergency alarm system) 

Function requirements, general 

IMPORTANT The circuit 15 ON status is sent by the electronic ignition lock (EZS) control unit (N73) via the interior CAN (CAN B) to the parameterizable special module (PSM) control unit (N26/16).

Emergency alarm, general 

The emergency alarm can be triggered by the driver if he/she feels threatened by someone. At the same time, a radio help call can also be triggered.

The emergency alarm function consists of the following subfunctions:

Function sequence for emergency alarm 

The emergency alarm can be activated by the taxi alarm system radio remote triggering transmitter (A8/4) (full alarm) or through the emergency alarm system activation button switch (S62/6) concealed in the driver footwell. An active emergency alarm is terminated by operating the emergency alarm system release button switch (S62/5).

Function sequence for silent alarm 

The silent alarm is intended to prevent the threatening person from noticing the alarm triggering. The silent alarm is requested by operating the emergency alarm system activation button switch. The parameterizable special module (PSM) control unit reads in the status of the emergency alarm system activation button switch directly, evaluates it and actuates the roof sign lamp (E14/4) at a frequency of 2.5 Hz. In addition, the exit and warning lamps of the left and right front door are actuated. The signal is sent by the signal acquisition and actuation module (SAM) control unit via the interior CAN to the left front door control unit (N69/3) and to the right front door control unit (N69/4).

Function sequence for full alarm 

In the event of a full alarm, the following functions are also triggered in addition to the output of the silent alarm:

The full alarm is requested by operating the emergency alarm system activation button switch or the taxi alarm system radio remote triggering transmitter twice within 3 s.

The parameterizable special module (PSM) control unit reads in the status of the emergency alarm system activation button switch directly. When the taxi alarm system radio remote triggering transmitter is operated, this sends the request to trigger the full alarm via the FM, AM antenna amplifier (A2/18), electronic ignition lock control unit (EZS) and interior CAN to the parameterizable special module (PSM) control unit. The parameterizable special module (PSM) control unit evaluates the request in both instances, and sends corresponding information via the interior CAN to the signal acquisition and actuation module (SAM) control unit (N10/1), which then evaluates this and initiates the alarm output. An acoustic alarm is output in the event of a full alarm. The signal acquisition and actuation module (SAM) control unit actuates the right horn (H2) and the left horn (H2/1) through the horn relay (K40/10kJ) at a frequency of 1.6 Hz. The signal acquisition and actuation module (SAM) control unit sends the signal to actuate the front interior lamp (N70e1) via roof LIN (LIN B13) to the overhead control panel (OCP [DBE]) control unit (N70).

It is reset by operating the emergency alarm system release button switch once. On the vehicle side the radio help call is also reset using the emergency alarm system release button switch; depending on the radio system however, it may be necessary to deactivate the radio help call in the radio system.

Function sequence for radio help call 

Depending on the programming, a radio help call can be made separate from or together with the emergency alarm.

The radio help call is started by:

The radio help call request is read in by the parameterizable special module (PSM) control unit and sent via the CIA CAN (CAN CIA) to the taxi two-way radio (A49). The taxi two-way radio forwards the signal via a direct line to the radio frequency roof antenna (A2/50).

The radio help call is then sent by the radio roof antenna to the taxi center. Depending on the programming, the actuation of a radio help call can occur "statically" or as a "pulse". For the "Static" actuation mode, when making a radio help call, the discrete output on the parameterizable special module (PSM) control unit is switched to the ground connection until the radio help call request is reset over the emergency alarm system release button switch. For the "Pulse" actuation mode, when making a radio help call the discrete output on the parameterizable special module (PSM) control unit is switched twice, with a break of 1 s between the pulses, for 1 s to the ground connection.

An active radio help call is terminated by operating the emergency alarm system release button switch. The status of the emergency alarm system release button switch is read in directly by the parameterizable special module (PSM) control unit. In addition, a restart of the two-way radio is necessary to reset the radio help call in the two-way radio.

Function sequence for display of fault messages 

On model 447.7 

The fault messages are shown on the multifunction display (A1/1p13) of the instrument cluster (IC) control unit (A1/1). Any faults and malfunctions are detected by the parameterizable special module (PSM) control unit, then stored and sent via the interior CAN to the instrument cluster (IC) control unit. The parameterizable special module (PSM) control unit also cyclically sends data logs via the interior CAN to the instrument cluster (IC) control unit.

On model 447.8 

The fault messages are shown on the multifunction display of the instrument cluster (IC) control unit. Faults and malfunctions are detected by the parameterizable special module (PSM) control unit, stored and sent via interior CAN, electronic ignition lock (EZS) control unit, chassis CAN (CAN E), gateway for the user interface CAN (N93/4) and user interface CAN (CAN HMI) to the instrument cluster (IC [KI]) control unit. The parameterizable special module (PSM) control unit also cyclically sends data logs to the instrument cluster (IC [KI]) control unit.

The following faults and malfunctions are shown in the multifunction display:

IMPORTANT For security reasons, the request for the full alarm through the radio remote triggering transmitter is automatically repeated after 10 s.

  Electrical function schematic for emergency alarm Model 447.7 PE82.25-S-2060-97TRA
    Model 447.8 PE82.25-S-2060-97TRB
  Overview of system components for taxi/rental vehicle   GF82.25-S-9890TRA 
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