Functional Scope Of Taxi Functions, PSM, Function - GF54.21-S-3011TRA
Model 447, 448
With Code ED5 (Parameterisable special module)
Except Code XM7 (MOPF II)
Taxi function
For the taxi functions including CANopen, the software components "CANopen stack" and "CANopen gateway" are adopted.
An abstraction level is used to adapt the signals of the interior CAN (CAN B) to the signals of the software components.
The event log corresponds to CANopen CiA447, it is issued on a private CAN interface.
Alternatively, the peripheral devices CAN, can also be issued on the same physical interface.
The CANopen interface is used for taxi functions.
Alarm function (With Code ZK2 (Taxi version with emergency alarm system))
A special equipment code can be used to provide an alarm function in taxi or special protection vehicles.
A triggered alarm causes the activation of various actuators which can be activated or deactivated by the diagnostic system. The alarm has highest priority when the actuators are activated.
A visual and acoustic alarm is triggered using the taxi alarm system radio remote triggering transmitter (A8/4) (maximum range approx. 40 to 100 m depending on location) or using the emergency alarm system activation button switch (S62/6).
The emergency alarm system has two stages:
- Silent alarm (1st stage, emergency alarm system activation button switch (S62/6) actuated once)
- Roof sign illumination flashes on and off
- Exit and warning lamps of the front doors are switched on
- Active alarm (2nd state, taxi alarm system radio remote triggering transmitter (A8/4) actuated once or emergency alarm system activation button switch (S62/6) actuated twice)
- Roof sign illumination flashes on and off
- Exit and warning lamps of the front doors are switched on
- Two-way radio switches to alarm mode
- Headlamps flash on and off
- Horn sounds at intervals
- Hazard warning system flashes on and off
- Front and rear interior illumination is switched on
Range information
The discrete wheel pulse counter signal is used by the taximeter (A50) for fare price formation.
This process is subject to the Weights and Measures Act. The complete signal path for the vehicle speed signal is checked and accepted by the responsible Bureau of Standards for each individual vehicle. Its correct operation is a requirement for registration of the vehicle as a taxi.
General conditions:
- No wheel speed pulses are issued with circuit 15 OFF.
- Pulse accuracy is assured as of a speed of 3 km/h
- If the parameterizable special module (PSM) control unit (N26/16) is in OFF mode, the output driver of the wheel speed signal is deactivated
The remaining description is based on the following definitions:
- Tire circumference of 2 m, 48 pulses/revolution (96 signal edges/revolution)
- Vehicle speed range of 0 to 362 km/h
- Wheel rotation speed of 0 rpm to max. 3016 rpm
This results in an output frequency of min. 0 Hz to max. 2414 Hz. There is a linear relationship between the wheel pulse counter and the vehicle speed.
Signal shape: Square wave signal with pulse/pause ratio of 50/50 (± 20 %). The maximum pulse width is 25 ms (±10 %).
For low speeds that would require a larger pulse width for maintaining the pulse/pause ratios of 50/50, the pulse width is set to a constant 25 ms (±10 %).
Object 6057: Pulses per wheel rotation
Pulses per wheel rotation: Object 6057 is filled as described in the "MGU routing table_CiA447".
The "Pulse per wheel rotation" value ("O6057_s_pls_per_whl_rot") is set statically to 48 pulses according to the specification.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | O6057_s_pls_per_whl_rot |
Enabling of "Object 6057"
Object 6057 is enabled as soon as the parameterizable special module (PSM) control unit (N26/16) is initialized.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | Actv_Object6057 |
Wheel pulse counter signal
The signal delay (CAN B "RIZ pulse" → Frequency maximum of discrete wheel pulse counter signal) is max. 250 ms. A timeout error for the reception message terminates the output of travel distance pulses. A few Signal Not Available values (SNA values) will not influence the output of the travel distance pulses. The last valid value is used. Output of the travel distance pulses is stopped when the Signal Not Available signal (SNA reception) is interrupted for one second (a valid wheel speed value retriggers the counter). The wheel pulse counter remains at the last valid value; the validity flag is set to Signal Not Available.
Discrete output of travel distance signal
Output of the 2-byte wheel pulse counter signal, identical to the "CiA447 RIZ signal", to the hardware abstraction layer (HAL).
An error distributor has also been implemented, which processes the fault memory entry depending on the "MFA_15 CutOff_Status".
An overload reset is not required, as this is conducted independently by the HAL.
A test signal of 530 Hz (±1 %) can be output via the input/output control. This corresponds to a vehicle speed of approx. 80 km/h.
The frequency change to the output signal per update/signal frequency change within an operating cycle may not exceed max. 20 Hz (20 pulses/s).
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| ISw_Stat | MFA_15_RIZ_DUTY |
| WhlRPM_FL | MFA_15_RIZ_FREQ |
| MFA_15_Overl_Cutoff_Stat (not used) | - |
If the ignition state and wheel speed are valid, the duty cycle and frequency are forwarded via pulse width modulation (PWM) to the multifunction output "MFA15".
The "MFA_15_RIZ_FREQ" frequency is calculated through "8*WhlRPM_FL". If the value is less than 120, "MFA_15_RIZ_DUTY" is set to "0", otherwise "MFA_15_RIZ_DUTY" is set to "5000".
Object 6055 Wheel pulse counter
Object 6055 is filled as described in the "MGU routing table_CiA447".
Determination of wheel pulse counter signal: The parameterizable special module (PSM) control unit (N26/16) reads the travel distance pulses at the output of the algorithm and "packs" these pulses into a 16-bit ring counter which is then read out every 100 ms (PDO cycle time) and is output to object 6055 h.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| ISw_Stat | O6055_s_WhlPlsCnt |
| WhlRPM_FL | - |
For a valid (!=7) ignition state "ISw_Stat >=4" and for a valid (!=16383) front left wheel speed "WhlRPM_FL<3017", the wheel pulse counter "O6055_s_WhlPlsCnt" is output on the CANOpen bus.
Determined wheel pulse counter validity
For a valid ignition state and a valid wheel speed, object 6055 "O6055_s_pcvalid" is set to "1" and output as "Pulse Counter valid". With (ISw_Stat!= 4 && ISw_Stat!= 5 &&!(ISw_Stat ==0x7)), pcvalid must be set to "0".
With ((ISw_Stat == 4 || ISw_Stat == 5) && WhlRPM_FL!= 0xFFFF), pcvalid is set to "1". If ISw_Stat is at Signal Not Available (SNA) (0x7) or WhlRPM_FL is at SNA (0xFFFF), then pcvalid must also be set to SNA (0x3).
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| ISw_Stat | O6055_s_pcvalid |
| WhlRPM_FL | - |
Enabling of object 6055 if values are valid
Object 6055 is enabled as soon as the parameterizable special module (PSM) control unit (N26/16) is initialized.
If the ignition state and wheel speed are valid, "Actv_Object6055" is set to "1".
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | Actv_Object6055 |
Object 6056 Wheel pulse counter overrun value
The object is filled as described in the "MGU routing table_CiA447".
For value, cf. "MGU routing table_CiA447" under "Standards →CiA447".
The wheel pulse counter overrun value "O6056_s_WhlPlsCnt_overrun" is sent with the "FFFFh" value.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | O6056_s_WhlPlsCnt_overrun |
Enabling of object 6056
The object is enabled and "Actv_Object6056" is set to "1" as soon as the parameterizable special module (PSM) control unit (N26/16) is initialized.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | Actv_Object6056 |
Reserved
The reserve value "3Fh" is reserved.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | O6056_s_r |
Object 6054 Wheel speed signal source
The parameterizable special module (PSM) control unit (N26/16) always uses the wheel speed information from the left front wheel.
Object 6054 is filled as described in the "MGU routing table_CiA447".
Wheel signal source
In this object, the parameterizable special module (PSM) control unit (N26/16) provides the source of the wheel speed value which is output via object 6054 h. The wheel speed signal source "O6054_s_whl_signal_source" is sent with the value "1" (0 left front).
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| O6054_s_whl_signal_source | - |
Enabling of object 6054 if values are valid
The object is enabled and "Actv_Object6054" is set to "1" as soon as the parameterizable special module (PSM) control unit (N26/16) is initialized.
Operated inputs and outputs:
| Inputs | Outputs |
|---|---|
| - | Actv_Object6054 |
| Overview of system components for parameterizable special module (PSM) | GF54.21-S-9998TRA |