Central Gateway (CGW) Control Unit, Basic Function - GF54.21-S-2012A
Model All (Light transporter)
Example illustration of model 420
Overview
This document contains the following information:
- General
- Function requirements
- Function
General
The central gateway (CGW) control unit is the central communication interface and performs central control functions in the vehicle. It acts as a data distributor for communication inside the vehicle and via a communication interface with the external world. It supports different bus systems (Ethernet, CAN, LIN).
Function requirements
- Circuit 15 ON
Function
The CGW has the following tasks:
- Central communication interface (gateway) between bus systems
- Distribute information that must be transferred among the bus systems.
- Allow diagnosis through the Internet and software updates
In normal vehicle operation, information which is present on one CAN and needed on another CAN for control unit functions is transmitted by the CGW.
Diagnostic bus
The diagnostic bus is primarily used for connecting an external test device to the vehicle. The control units are diagnosed in diagnosis mode using the test device.
Interface function (gateway function)
With the gateway function, a distinction is made between 2 function types: In diagnosis mode, with the external test device connected, the diagnostic query messages of the test device are transferred to the diagnostic bus and forwarded to the CGW. The CGW then sends the diagnostic query messages to the corresponding control units of the bus system. In reverse, the diagnostic response messages are sent from the control units of the bus system to the CGW. The CGW then transfers these diagnostic response messages to the diagnostic bus. The test device reads in these diagnostic response messages from the diagnostic bus. This interface functionality is called a diagnosis gateway.