Your questions suggest I have not been clear. There are two contributors to the problem that I am working through.
1. The NI-XNET driver implementation
2. The communication specification that I am working with.
XNET driver: The XNET driver when in Frame Input Single Point mode will return an array of data when performing a read action. This array will contain all frames that the session was initialized with, regardless of whether or not data was received on the bus. However, the payload of the frames not received will be all 0's.
Comm Spec.: When sending a "Command" frame the data is sent across the bus with an unused payload (the receiver is keying on the arbritration ID) this payload may contain any data including 0's, which is often the case.
Pair the two of these together and I have little that I can key off of to tell if a frame read back from the read action is actually a received frame. I am currently using the timestamp but I am not sure how reliable this is going to be.
Specifically answering your questions.
So, you're saying that when the session is initialized, a device on the CAN bus sends a bunch of frames with empty payloads?
No, I'm saying that this is what the read action returns
And then there are additional "Command" messages that are also being sent with empty payloads?
All of the "Command" messages are sent with empty payoads
When you first start the Frame In session, how many empty frames do you see?
If you start a Frame In Single Point session and perform a read action you will receive all frames the session is initialized with.
BTW: An implementation of the Event remote and Cyclic remote timing modes that would allow me to assign an ID combination would have made this implementation easy.
