Read the transmit/receive error counter from CAN

[dre99gsx]

I would like to read every packet that runs accross the CAN bus. I am in a situation where my Can Receive.vi is set to read any CAN bus errors, but I would like to see the entire can packet(including CRC values, DLC values, etc etc). Is there a way to do this? Any sample vi's out there?

Also, I'de like to read the status of the receive/transmit error counter on either side I assume. I am trying to see what my arbitration values hover around (less than 128, over 128, etc etc).

Thanks for any help.
Andre

[biker2000]

Hi Andre

The NI CAN hardware does not have the ability to access the full raw CAN frame. This is because of the used CAN controller (Philips SJA 1000 on Series 2 CAN hardware) does which does not provide all of this information. However, the following data is provided:

• Arbitration ID (11 or 29 bit)
• Data Length (DLC)
• Remote Frame Flag (RTR)
• Data (0-8 byte)

As you are interested in the raw/unconverted CAN data, you should focus on the NI-CAN Frame API, as the NI-CAN Channel API tries to abstract these information.

With Series 2 CAN hardware, you have read access to the receive/transmit error counter. Take a look at the ncGetAttr function (Frame API) or the GetProperty function (Channel API) and query the ‘Series 2 Error/Arb Capture’ attribute or the ‘Interface Series 2 Error / Arb Capture’ property for that. You can find more details on how to read the returned data in the help for the two functions.

-B2k