USB to CAN interfaces

Background info

All IQAN masters on the IQANdesign platform supports diagnostics over CAN, but on e.g. IQAN-MD3 and IQAN-MC2 there is a choice between two communication interfaces between the PC and the master module:


  • USB
  • CAN

For the modules with both CAN and USB, CAN is the preferred diagnostic interface.
While USB is an interface that is fast and available on any laptop; it has some inherent limitations. Due to its high speed and low signal amplitude, it is sensitive to disturbances. When performing run-time diagnostics such as measure on a mobile machine, this can lead to problems with constant termination of the measurement.
Another issue when connecting a PC directly to a master module is that there is a risk of damage due to voltage variations causing over current in the USB-ground. Therefore, connecting without galvanic isolation should be avoided.



Recommended interfaces

By using an isolated USB-CAN interface, it is possible to have an interface that is both robust to interference and that can survive voltage variations.
The CAN adapter needs to be supported by the IQAN software, currently the following models work:


  • National Instruments NI USB-8502  (www.ni.com): Isolated. The earlier NI USB-8473 also works. 
  • IXXAT USB-CANcompact (www.ixxat.com): Make sure to get the isolated variant.
  • Kvaser Leaf Light (www.kvaser.com): Several models exists, most or all isolated.
  • Parker Vansco USB-DLA : Not isolated. Requires IQANdesign 2.60.34 /IQANrun 2.60.29 or later. Does not work with IQANanalyze.
  • CAT CA3: Requires IQANdesign 2.60.34 /IQANrun 2.60.29 or later. Does not work with IQANanalyze.
  • PEAK PCAN-USB (www.peak-system.com) Requires IQANdesign 4.06, IQANrun 4.06 or IQANanalyze 4.06, or later.

Use diagnostic CAN bus

If possible, there should be a dedicated bus for PC-diagnostics on the machine. If this is not possible, PC-diagnostics can be mixed with expansion modules or J1939, but the amount of traffic on that bus needs to be limited.


Multiple master modules

With a multi-master system built in IQANdesign 3 or later, all masters are connected to the Diagnostics bus, this bus should be used for PC diagnostics.
If the master modules are on version 2.x, multiple master modules can also be connected to one bus for diagnostics, then each master must have a unique address, and connection can only be made to one master at a time.


Using the PC tools

Select CAN under communication options. Unlike USB, the USB-CAN adapter needs to be connected to the PC before IQANdesign/IQANrun is started. If communication does not work, restart IQANdesign/IQANrun.
The connection to the master module is established as soon as you start an online operation, e.g. send application, adjust or view logs.


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