Caravan Control Unit Bus Connection, Function - GF54.21-D-5046TSA
Model 447
with code JA3 (Intelligent body control.)
with code XM7 (MOPF II)
Model 907, 910
with code JA3 (Intelligent body control.)
Block diagram of MBAC Stage I
Block diagram of MBAC Stage II
General
Bodybuilder manufacturer (ABH)
Mercedes-Benz Advanced Control (MBAC)
High speed video link (HSVL)
Universal serial bus (USB)
The MB Advanced Control, control unit (N175) consists of two stages: MBAC Stage I and MBAC Stage II.
MBAC Stage I
MBAC Stage I has the following interfaces:
- I/O interface
- MBAC CAN bus interface
- ABH CAN bus interface
- LIN interface
- Bluetooth® interface
I/O interface
The MBAC is designed so that the assignment of the I/O interfaces is configurable. The assignment of the I/O interfaces is configured by the bodybuilder manufacturer.
An example configuration for the assignment of the I/O interfaces with analog inputs and outputs, as well as digital inputs and outputs, is shown in separate documents
MBAC CAN bus interface
MBAC Stage I has exactly one MBAC CAN bus interface.
The MBAC CAN bus can enable the external expansion of the I/O scope through additional I/O modules networked over the MBAC CAN bus.
The MBAC CAN interface of the MBAC makes it possible to connect an external PC, which, as a temporary device, performs software updates for MBAC Stage I and runs XENTRY Diagnosis.
The I/O modules are connected by CAN messages that are assigned according to a fixed schematic. The CAN IDs of the various I/O modules are formed by a basic address together with an offset, which is defined by hardware coding. The messages are protected by a 4-bit message counter as well as a 4-bit cyclic redundancy check ("CRC").
ABH CAN bus interface
MBAC Stage I has exactly one ABH CAN bus interface.
The bodybuilder manufacturer CAN (CAN ABH) makes the connection to the base model vehicle. The end point of the connection on the vehicle is the parameterizable special module (PSM) control unit (N26/15).
All required information and connections are provided by Daimler, e.g. the following information:
- Terminal signals (ignition)
- Additional information about the vehicle (central locking system, rear interior lighting, language settings, time, fuel level)
- Touch events and video mode of central display
- Diagnosis connection
LIN interface
MBAC Stage I has exactly one LIN interface. The 60 available LIN frames mean that the LIN bus can provide a logical connection for a maximum of 30 slave devices; physically, a maximum of 16 slaves is possible.
Bluetooth® interface
The MBAC has a Bluetooth® radio interface for connecting an external antenna. This connection is provided via the Rosenberger FAKRA 59S 2UQ-40M T5-K plug type. The coding of the Bluetooth® antenna connection is Curry (K).
A reliable Bluetooth® connection to the MBAC is guaranteed within the vehicle and within a radius of a few meters around the vehicle. For this, an external Bluetooth® antenna with sufficient reception and transmission output is installed at an optimum position. The optimum position is on the side of the vehicle opposite the living area door, between the B-pillar and C-pillar. Actuation occurs with power category 1 components.
MBAC Stage II
MBAC Stage II has the following interfaces:
- Ethernet interface
- I/O interface
- MBAC CAN bus interface
- ABH CAN bus interface
- LIN interface
- USB interface
- Bluetooth® interface
- HSVL interface
Ethernet
MBAC Stage II has at least 4 Ethernet interfaces.
Each MBAC Ethernet interface is designed so that the Ethernet interface of MBAC Stage II supports a defined data transfer rate in Mbit/s.
The Ethernet interface allows an external router to be connected to extend the network with IP components or to use the router for independent, SIM card-based internet access.
I/O interface
The MBAC is designed so that the assignment of the I/O interfaces is configurable. The assignment of the I/O interfaces is configured by the bodybuilder manufacturer. An example configuration for the assignment of the I/O interfaces with analog inputs and outputs, as well as digital inputs and outputs, is shown in separate documents.
MBAC CAN bus interface
MBAC Stage II has exactly one MBAC CAN bus interface.
ABH CAN bus interface
MBAC Stage II has exactly one ABH CAN bus interface.
LIN interface
MBAC stage II has exactly one LIN interface.
USB interface
MBAC Stage II has a USB interface.
The MBAC can be updated through the USB port. As when updating the system software, the system configuration is also transferred over the MBAC CAN bus interface. This is also done using a software tool and the USB-to-CAN adapter on the MBAC interface which transfers the encrypted and write-protected configuration file.
To ensure that all vehicle components were correctly configured, the system is then checked in full by the bodybuilder manufacturer. The system test also takes place over a USB connection to the MBAC CAN bus and is carried out using an End-of-Line testing tool. This makes it possible to successively read out or respectively set the values of all components based on the specified configuration.
The gateway software can be updated using Windows PC software which is connected to the MBAC CAN bus with a USB-to-CAN adapter. A physical CAN interface is provided in the vehicle for this purpose.
The transfer of new software is protected by security mechanisms that prevent the use of unofficial versions. After successful transfer and application of the new software, the system is automatically restarted.
The new operating system, as well as the required frameworks and user applications, can be updated over the USB interface. After starting the process and checking the digital signature of the update files present on the USB flash drive, the update process then proceeds largely automatically.
Bluetooth® interface
The MBAC has exactly one Bluetooth® interface for connecting an external antenna.
HSVL interface
MBAC Stage II has two HSVL interfaces to which two displays can be connected.
The coding for the first HSVL interface is blue and the second is green.
Each HSVL interface of MBAC Stage II supports a resolution of 1920 x 720 pixels or 1280x 720 pixels. The resolution can be changed through XENTRY Diagnosis.
| Overview of system components of caravan control unit | Model 907, 910 | GF54.21-D-9992TSA | |
| Overview of system components of caravan control unit | Model 447 | GF54.21-S-9992TMA |