Special vehicle multifunction control unit, function - GF82.25-P-4102-04T
Functional preconditions
- No overvoltage or undervoltage
- Circuit 30 or circuit 15 (emergency alarm functions already active at circuit 30)
Functions for taxi and special-purpose vehicles are integrated into the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9).
These functions encompass:
- taxi emergency alarm (taxi/rental car)
- taxi electrical system (taxi/rental car)
- panic alarm function (private customers)
- part of the danger alarm system (GAS) (government and special protection)
- part of special signal actuation (SOSI) (police and emergency vehicles)
- heated windshield (HWS) (special protection vehicle)
- disabled person control functions (disabled person vehicle)
There is only one configuration status on the hardware side for the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9). Depending on the vehicle model, inputs and outputs are in part differently connected and actuated.
The activation of the necessary functions in the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) takes place through a set bit in the message from the central gateway control unit (N93).
This message is sent cyclically to the CAN interior. The programming of these bits must be performed in the central gateway control unit (N93).
In the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) additional subfunctions or options can also be released. This programming is done using Star Diagnosis and is written to the EPROM of the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9). Programming is retained after switching off the control unit.
The special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) is supplied in the vehicle via the circuit 30, in other words voltage is always applied. In normal mode (no alarm, no disabled person functions via CAN interior) the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) does not require the CAN interior and signals bus sleep readiness.
If in the event of an alarm, actuators have to be activated via the CAN interior, then the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) activates the CAN interior and signals activation of the components.
System states
The special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) switches from active mode into the sleep mode if the following conditions have been fulfilled (if equipped):
- CAN interior sleeps
- No alarm triggered
- Circuit 15 and circuit 15R off
- Circuit 58d is zero
- Roof sign lamp (E14/4) switched off
- Short circuit not detected
- Taximeter control unit (A67n1) signals occupied or OFF
- Line to alarm button not faulty
Before each transition into the sleep mode the supply outputs active at circuit 30 ON are subjected to a load assessment.
A check is made as to whether the output can be switched off before the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) changes into the sleep mode.
If the connected consumers require a current of < 1 mA, then the internal FET (Field-Effect-Transistor) is switched off in order to lower the current consumption of the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9). The required load current of a maximum of 1 mA then supplies a pull-up resistor.
If the current requirement is higher then the FET (Field Effect Transistor) is switched on. Every time the FET (Field-Effect-Transistor) is switched on, the own current consumption in the special vehicle multifunction control unit (MSS) (N26/9) increases by 1.5 mA.
Different wake-up conditions apply to taxis, special-purpose vehicles and vehicles for handicapped persons:
| Wake-up condition | Taxi | Special vehicles | Vehicles for handicapped persons |
|---|---|---|---|
| Actuation of the alarm pushbutton | Yes | Yes | No |
| Defective line to the alarm pushbutton | Yes | No | No |
| Activation of the input for the roof sign control line | Yes | No | No |
| Activation of the input for interior light (video) | Yes | No | No |
| Wake-up through active CAN bus | Yes | Yes | Yes |
| Short circuit at supply output if output is activated | Yes | Yes | No |
| Load current is higher than 1 mA if supply output is not activated | Yes | Yes | No |
| Wake-up via RS485 bus | Yes | No | No |
Switching off in the event of undervoltage
The signals for the consumer cutout are put on the CAN interior by the central gateway control unit (N93). The switch-off stages are differentiated between two priority stages.
The special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) receives the cutout signal, calculates the priority stage and immediately switches off the appropriate outputs (consumers).
| Output | Cutoff stage 2 Prio 1 | Cutoff stage 1 Prio 2 | Special-purpose vehicle: Non-disconnectable | Current consumption max. | Current consumption Average |
|---|---|---|---|---|---|
| Taxi roof sign | X | 5A | 2,5 A | ||
| Radio help call | X | 250 mA | 10 mA | ||
| Two-way radio supply | X | 4A | |||
| Taximeter supply | X | 1,5 A | 1 A | ||
| Socket 1 | X | 10 A | 1 A | ||
| Socket 2 | X | 10 A | |||
| Door contact | X | 100 mA | |||
| Circuit 58d | X | 500 mA | |||
| Circuit 15R | X | 500 mA | |||
| Circuit 15 | X | 250 mA | |||
| Circuit 15, 15R, 15C | X | 500 mA | 50 mA | ||
| Circuit 30 | X | 500 mA | 50 mA | ||
| Circuit 58d | X | 500 mA | 150 mA | ||
| Distance | X | 150 mA | 50 mA | ||
| Battery indicator | X | 250 mA | 50 mA | ||
| Two-way radio hands-free facility | X | 250 mA | 10 mA | ||
| 2nd battery | X | 250 mA | 100 mA | ||
| Horn contact | X | 100 mA | 20 mA | ||
| Two-way radio help call/seat contact | X | 250 mA | 20 mA | ||
| Two-way radio set 1 | X | 5A | 1 A | ||
| Two-way radio set 2 | X | 5A | 1 A | ||
| Circuit 15 (1A) | X | 1,5 A | 1 A | ||
| Flash lamp HD | X | 4A | 4A | ||
| Circuit 30 (10A) | X | 10 A | 5A | ||
| Circuit 15 (10A) | X | 10 A | 5A |
Special signal actuation
When the identification lamps are switched on, one of the two inputs
- identification lamp at L /ground active or
- identification lamp at H /plus active
of the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) is activated.
As a result, the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) triggers light signals that flash on and off.
In doing so, the following actuators are controlled depending on the programming:
| Output | Function | Description |
|---|---|---|
| Flash lamp HD | Output/4A plus active | Statically active or flashing on and off with 1 Hz (programmable). The activation only takes place at circuit 30 if the trunk lid is open. (connection of flash lamps in the trunk lid.) |
| High beam | CAN | Flashing on and off with 1 Hz/actuation via CAN |
| Fog light | CAN | Flashing on and off with 1 Hz/actuation via CAN The following options can be programmed:
Furthermore, it is possible to program that the fog lamp is to be statically activated. |
| Low beam | Statically on/actuation via CAN |
It is possible to program which actuators are switched off in the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) in order to protect the battery, if circuit 15R is missing:
- Fog lamp off (if the fog lamp was activated statically),
- Low beam off.
In both cases only the standing lamp remains activated.
By programming a light version it is possible to specify which actuators are to be actuated by the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) for the SINFO function.
| HD flash lamps are activated | No | flash on and off with 1 Hz | statically active | |
| High beam is activated (1 Hz) | No | always | if bright | if dark |
| Fog lamp is activated (1 Hz) | No | always | if bright | if dark |
| HD flash lamps are activated | No | flash on and off with 1 Hz | statically active | |
| Activate fog lamp statically | No | always | with circuit 15R | |
| Low beam | No | always | with circuit 15R |
The following boundary conditions apply:
- Manually switched on fog lamps or high beams always have a higher priority. To do this, the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9) evaluates the request from the steering column switch and takes back its request upon activation.
- The high beams and fog lamps only flash on and off with circuit 15R ON.
- The flashing lamps in the trunk lid are actuated with circuit 30 ON.
- To evaluate the light information, the status of the rain/light sensor (B38/2) is interpreted in the overhead control panel control unit (N70). The status of the low beams is not evaluated until the overhead control panel control unit (N70) sends the message that the rain/light sensor (B38/2) is defective.
- If the high beams and fog lamps are activated together via the CAN interior, they will flash on and off alternately. Furthermore, in the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9), it is possible to program the duration (brightness phase) during which the two light sources are to be activated while flashing on and off.
Panic Alarm System (GAS)
The alarm is triggered by operating an alarm activate button in the vehicle's interior and has one stage. The alarm is canceled by operating the reset button one time. The GAS function has to be enabled in the special vehicle multifunction control unit (SVMCU [MSS]) (N26/9).
Standard function:
- Output two-way radio emergency call is activated
- Flash high beam on and off
- Flash turn signal indicator lamp on and off
- Central locking closes
- Tilting/sliding roof closes
- All windows close (with or without obstruction sensor)
- Recirculated air flaps close