Can Data Frame - ABB FCAN-01 User Manual

90

CAN data frame

CAN employs data frames for transferring data between the host
(controller) and the nodes on the bus. The following figure
presents the structure of the data frame.
ARBITRATION FIELD
COMM.
START OF
OBJECT ID
FRAME
(COB ID)
1 BIT 11 BITS
(OR 29 BITS)
FUNCTION CODE
10 9
Communication
object
NMT
SYNC
TIME STAMP
EMERGENCY
PDO1 (Tx)
PDO1 (Rx)
PDO6 (Tx)
PDO6 (Rx)
PDO21 (Tx)
PDO21 (Rx)
SDO (Tx)
SDO (Rx)
NODEGUARD
1 = IDE bit = Extended format / standard format (1 bit)
2 = ro = reserved (1 bit)
3 = DLC = Data Length Code (4 bits)
Communication
Header
CONTROL
FIELD
REMOTE
TRANS-
MISSION
REQUEST
1
(RTR)
1 BIT 6 BITS
8 7 6 5
Function code
(Binary)
0000
0001
0010
0001
0011
0100
0101
0110
0111
1000
1011
1100
1110
REDUNDANCY
DATA
FIELD
2 3
0 TO 8
BYTES
NODE ID
4 3 2 1
COB ID
(Hex)
00h
80h
100h
81h...FFh
181h...1FFh
201h...27Fh
281h...2FFh
301h...37Fh
381h...3FFh
401h...47Fh
581h...5FFh
601h...67Fh
701h...77Fh
CYCLIC
ACKNOW-
LEDGE
CHECK
FIELD
(CRC)
16 BITS 2 BITS
0
COB ID
(Dec)
128
256
129...255
385...511
513...639
641...767
769...895
897...1023
1025...1151
1409...1535
1537...1663
1793...1919
END OF
FRAME
7 BITS
0