Some pieces of CAN hardware (but not all) support a feature called Transmit Echo. When enabled, they include all messages they are commanded to transmit on the bus line, as well as the messages they receive in their internal list of transitions. This enables viewing of the actual time stamp of transmittal. When bus loads are high and arbitration defeats are possible, the actual timestamps may differ slightly from the MxVDev transition list.

The figures below show where these features are located in MxVDev Network Configuration and in MxTransIt respectively. By default, Tx Echo is disabled on most devices.

Tx Echo Property in Network Configuration

Tx Echo Property in Network Configuration

 

Tx Echo Property for Vector CANtech Transform

Tx Echo Property for Vector CANtech Transform

 

Once enabled, you can add the Tx Echo Signal to a TestCase. It is not a standard Signal, so you have to add it as a probe from the expanded Signal list:

TxEcho3-marked

This Signal echos all messages on the bus (transmit and receive), giving a better indication of when messages are actually reaching the bus.

 

Related Topics:

CAN Device Interface Transforms

Network Configuration

Bus Overview

CAN Transforms (Signal Processing Transforms)