CANstressD and CANstressDR

A tool for providing resistance on the Network

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CAN networks are highly tolerant with regard to disturbances of the bus communication and failures. If a CAN node fails, it is automatically disconnected from the bus and thereby does not disturb the remaining bus operation . In order to test whether a system is behaving as it should with regard to disturbances or failures, a device is needed to disturb the CAN bus, its physical properties and the logical levels (recessive and/or dominant) in a targeted, reproducible way. With CANstressD ( Digital) or CANstressDR ( Digital and Resistor Network), the CAN developer has the ideal comprehensive disturbance instrument.

Features and Advantages

CANstress is a standalone hardware module that is inserted directly onto the CAN bus. It contains various triggering conditions and disturbance logics. The fully equipped module includes a number of resistors that can be software-controlled. These resistors are used to force different bus levels onto the bus lines by limiting the voltage supplied.

Functions

CANstress supports a range of error and test modes, e.g:

• Emulation of line failures
• CAN system failures
• Accompanying development tests of electronic control units
• Disturbances of CAN controllers
• Programmable short circuits and interruptions

A programmable static capacitor inserted between the bus lines can be used to simulate various line lengths.

Application Areas

Reproducible simulation of bit corruption:

• Error statuses in accordance with ISO 11519-2 (line/line short circuit, line/supply voltage short circuits, interruptions)
• Simulation of creeping failures
• Targeted imposition of bus levels

Examination of disturbance handling by CAN systems:

• Test environment for the development of CAN controllers and CAN nodes
• Targeted disturbance of bus nodes by destruction of its CAN messages at any bit position
• Targeted manipulation of bit fields within the CAN messages (SOF, arbitration, data, CRC, ACK, etc.)
• Testing the behaviour of the bus nodes in the event of errors
• Triggering of external devices

Inspection of recovery behaviour after disturbances in ECUs

Activation of the disturbance

When CANstress is in the neutral position, the bus is undisturbed. When the system is triggered, the configured disturbance sequence becomes active. The disturbance sequence consists of a sequence of interfering pulses at the bit level or the BTL level. A single disturbance pulse can force a dominant or recessive level on the bus, or leave the bus unaffected.

The disturbance of the CAN system is initiated by the following trigger sources:

• Triggering on CAN bit fields: maskable content of the bit fields within messages of standard or extended format
• Triggering on error frames, on the start-of-frameedge, the end-of-frame, bus idle sequence or any maskable bit sequences
• Triggering via the CANstress software
• External trigger: voltage signal at the trigger input (TTL level)

The following disturbance modes are available:

• The disturbance persists for a specified period.
• The disturbance persists until manual stop.
• The disturbance persists as long as the trigger is active.
• The disturbance sequence is initiated after a trigger for a definable number of trigger events.

Integration of CANstress

Optimum development and test environments are achieved through the use of a CANstress module together with the other analysis tools of the Vector tool chain, such as CANalyzer, CANoe, and CANscope. With CANstress, targeted disturbances are generated, a detailed analysis of the effects of the disturbance at the physical level is provided with CANscope. Via the COM automation interface CANstress can be integrated into automated test environments like CANoe.

Integrated database CANdb++

As with other CAN tools from Vector, CANdb++ is completely integrated. Messages and signals can easily be configured out of CANdb databases.

Scope of supply:

• CANstress disturbance module
• Configuration software for MS Windows 9x/NT/2000/XP
• Cable set and power pack