Vector VN8970 User Manual download pdf (Page 18)

Chapter 2. Background

with the lower ID will succeed. The node trying to transmit the message with the

higher ID will wait and try again.

2.2 Software Test Rig

During testing it is necessary that the ECU is connected to the testing equipment

in a fashion similar to the car it is supposed to be ﬁtted to. The test rig, to which

the ECU is connected via CAN during testing, is capable of simulating a whole

car, with all its CAN nodes, if necessary. It also offers the possibility to connect, or

simulate, sensors and actuators so that the testing environment becomes as close to

reality as possible.

The test rig is based on a 19” rack cabinet and consists of different modules:

• Power module, capable of delivering high currents since the pump during

brief moments might be under heavy load.

• Pump module, containing four different pumps to simulate different scenar-

ios; normal, pressure too high, pressure too low and pump with stuck motor

axle.

• Fault injection module, containing equipment to simulate external hardware

faults such as short circuits, power loss, disconnected pump, etc.

• VT-system or VN8970 module, see below.

VT-system

The VT-system, developed by the company Vector Informatik GmbH [8], is the

”heart” of the test rig and the main part of it is its real-time module which basically

is a computer that simulates the car to which the ECU is connected. The real-time

module is used to enhance the performance by running the real-time parts of the

CANoe tests on a dedicated platform rather than the user PC, which often has a lot of

different processes running at all times. It is accessed from the user PC by Ethernet

which does not affect the behaviour or performance of the real-time system.

The system is modular in itself and consists of, apart from the real-time module;

a CAN network module, general purpose relay and analog-/digital I/O modules and

a couple of power modules, see Figure 2.2.

VN 8970

The VN8970, also from Vector [14], is similar to the VT-system in that sense that it

is also running a real-time computer and CANoe in order to simulate the imaginary

car. It differs in that it is not a modular system with the capability to expand with

modules such as I/O and relay modules. It does, however, comprise several CAN-

bus channels and a general I/O port, see Figure 2.3. For the scope of the thesis work

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Vector VN8970 User Manual Page 18