Campbell Scientific SDM-CAN Datalogger to CANbus Interface - Manual (Page 63)

Appendix D. Examples of CAN Data
Frames and Data Encoding and
Decoding
This Appendix gives examples of typical CAN data frames with worked examples of how to
encode or decode such data using the SDM-CAN.
Bits are Transmitted (Txed) or Received (Rxed) starting from the left of the data frame.
Txed/Rxed first Txed/Rxed last
64bit Data Frame
Bit order within
bytes
87654321 87654321 87654321 87654321 87654321 87654321 87654321 87654321
Byte order Byte 1 Byte 2 Byte 3 Byte 4 Byte 5 Byte 6 Byte 7 Byte 8
Right Hand Ref 64 57 56 49 48 41 40 33 32 25 24 17 16 9 8 1
Left Hand Ref 1 8 9 16 17 24 25 32 33 40 41 48 49 56 57 64
For the Left Hand Reference, some manufacturers may number the bits in the
following order:
Left Hand Ref 8 1 16 9 24 17 32 25 40 33 48 41 56 49 64 57
An additional variation is that sometimes the bit numbering starts from 0
instead of 1.
16bit Data Frame
Bit order within bytes 87654321 87654321
Byte order Byte 1 Byte 2
Right Hand Ref 16 9 8 1
Left Hand Ref 1 8 9 16
Data encoded/decoded from right to left in all cases.
D-1