NI 9853 CAN frames lost

[_Tom_]

Hello,

my setup is a cRIO 9116 with a NI 9853 CAN card. I permanently read on both CAN1 and CAN2. Busloads are about 8 % on CAN1 and 20 - 30 % on CAN2 at 500 kbit/s. So far everything is fine. Recently i added some loops which permanently send CAN messages on CAN1 or CAN2 in parallel to reading. I noticed that when CAN receive busload is about 30% and i do 4 CAN transmit loops with 100 ms period then it starts to loose frames in the receive loop. I guess it is because arbitration is blocking the CAN port too long to get all frames.

regards

Thomas

[Taki1999]

Can you post your code or a snippet?

Your busload on CAN2 seems a bit high but it seems odd that the addition of 4 more CAN transmissions would result in lost frames.

[_Tom_]

I cannot post a code snippet atm. But what I am seeking is some information about how much such a NI 9853 can handle, assuming it is proper programmed in FPGA. I thought it can handle reading 100% busload at 500 kbps or even 1 mbits. But what about if there is reading and writing in parallel? I will post the FPGA code later but there is some more stuff done with the CAN messages which I then need to explain (i don't want to remove cause maybe that's the problem).