By sending more than 8 bytes over CAN, you automatically need to follow a standard of some sort for a higher level transport protocol such as J1939. If you have higher level drivers that give you access to the transport protocol running over CAN, then you are set. NI provides an add on toolkit for UDS / KWP200 / ODB transport protocols, but none that I know of J1939. The do have an application example for J1939 somewhere though.
Also, the only examples provided for J1939 here are based on the frame API, which precludes you from using the channel API with a CAN database on the same port. I do not think that BAM messaging or TP is worked into their example, so you would need to buy the SAE spec and add code to their example.
I assume you are trying to read something like active DTC codes, and you have more than one so the node you are communicating with wants to send you a BAM, prior to the spew of packets holding the array of DTCs. Is that right?
By the way, DMC recently developed a set of J1939 protocol drivers for LabVIEW which are based on the NI-CAN channel API. The drivers are written in LabVIEW just like the example, but provide functions at a layer above the base CAN channel API layer. This allows the simultaneous capture of data from both J1939 packets which are simple broadcast CAN frames, or more complex transport using BAM, including extended data frames.
