can bus labView data difference

[stevesteve]

I have a NI USB-8473 Can Bus & am using the 'Transmit receive same port' NI example vi, used in extended mode. When data is put on the Can bus (by another device) the LabView 'ReadNetMult' function reads it but always gives a '3' rather than a '1' in the first digit of the arbitration ID.

eg

Actual CanBus Arb = 0x19999999

LabView Read Arb = 0x39999999

Baud 250000, data length 8, extended mode.

I know the first digit should definitily be a '1' and have confirmed this with a CanAnalyser; why does this NI/Labview example set up always  gives a '3' rather than a '1' for the first digit in any Can Message on the bus?

[JB]

Because NI uses the 30th bit to identify extended or standard arbitration ID.

Read messages 1, 3 or 4 of this search for more details.