How do I calculate the CAN arbitration ID right?

[GPIB_Guru]

Between packets on the CAN bus, you must have 11 bit-times of idle (value=1) on the bus. If you do not see 11 bit-times on your trigger, than you did not get the actual start of the frame.

[RT_1979]

If so, you only got to invert my bit-array... because I see the 11 bits between the packages....

[GPIB_Guru]

Inverting your array looks better, but not perfect:
<< Value>
1011 1010 0000 (1) 0010 010 1 0010 1111 1(0)110 0110 1110 1110 1001 01111

<< Inverted, removed bitstuff >>
0100 0101 1111 1101 1010 1101 0000 0001 1001 0001 0001 0110 1000 0

<< Split into fields >>
Got: 0    100 0101 1111    1   1    01 1010 1101 0000 0001   1   0  0   1000    10 0010 1101 0000
     SOF    11-bits ID    SRR IDE        18 bits ID         RTR  r1 r0   DLC          CRC

<< Interpret>
ID: 1 0001 0111 1101 1010 1101 0000 0001 = 0x117DAD01
RTR: 1 = Remote Frame (no data bytes)
r0/1: 0s (expected)
DLC: 8
CRC: cut off after 14 bits. Expected to see 15-bits plus extra recessive delimiter
ACK: missing

[RT_1979]

Seems like i need to improve my knowledge about CAN BUS.  Does anyone know a comprehensible paper for me, where the shortcuts are described?

One more question: In my instruction manual it is said, that the black box works under CAN 2.0b standard. Is tihs compatible to the NI CAN CARD´s??

Thanks for all your help so far!

RT

[RT_1979]

Message Edited by RT_1979 on 11-21-2006 09:37 AM