Dynamically change CAN message payload length in XNET

[hex_cro]

Any news?

Is there a possibility to filter by ID read can messages by XNET? I have to determine the receiving time of a single can message without using timestamps, because they are different between PXI and the device that send me this message (PXI send a CAN message to the device and it answer with a CAN message). I am using Frame Input Stream and Frame Output Stream XNET sessions.

Bye.

[GPIB_Guru]

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@hex_cro wrote:

Any news?

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No. Unfortunately, I still don't understand the use case for this request. That doesn't mean it isn't valid, but without understanding the rationalle, I am not sure how to classify this. Do you want to do this for fault injection?

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@hex_cro wrote:

Is there a possibility to filter by ID read can messages by XNET? I have to determine the receiving time of a single can message without using timestamps, because they are different between PXI and the device that send me this message (PXI send a CAN message to the device and it answer with a CAN message). I am using Frame Input Stream and Frame Output Stream XNET sessions..

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Sorry. I don't know if I understand this either. You need to know the time you received a frame, but you don't want to look at the timestamp? I am not sure how to determine time otherwise. If you want filtering to detect a single frame, you can use a frame input session instead of a stream input session. This will only return data for one ID. However, to determine when a frame was received, you would still need to look at the timestamp.

[hex_cro]

I am not using a frame input session because I have to transmit messages with a variable payload length and same ID. If I create two frame with same ID and different payload length, I have an error. What is wrong with my approach?

I have to send to the device messages with different payload length to communicate with it in diagnostic mode.

Now, I measure the time between transmission and receiving using MsTimer.

[GPIB_Guru]

Well, you need stream output to do the transmissions of different lengths, but you should be able to use frame input to do the reading.

[hex_cro]

The problem is I have to change payload length without starting and stopping CAN session: is this possible?

[GPIB_Guru]

I think for input objects, if the received payload is < DB, you are okay. So if you set the DB length to 8 bytes, then any frames <= 8 bytes will be received and passed up to you.