I'm confused by this parameter, which while part of the CAN data cluster fed to the CAN WRITE vi, and read from the CAN READ vi, can't even be found by searching for "DataLen" in the NI Embedded CAN for sbRIO Help file (for LabVIEW 2012).
I can see potential use for it: Have the Payload array always contain 8 elements (CAN maximum), and have the DataLen return the true length of the payload, among others. But I hate to speculate on it's use. In my current project, I built a 1M element array of CAN packets to use as a FIFO, each cluster element having 8 elements in the Payload array, to facilitate using the In Place Element structure to place new clusters into the buffer array. It would be nice to assume the DataLen will be the true length of the data, so I don't have to execute an "Array Size" command to determine this from the CAN READ vi, and don't have to substitute the CAN payload into an 8-element array before placing the element into my buffer. Again though, I hate to speculate.
Please point me to any documentation on this or if the answer is simple and brief, please reply here!
Thanks,
Erik