B&B Electronics HVD100A3 manual Arbitration Field Y1, Y2, Y3, Y4

Data messages received from the HDV100A3 operating in the J1939 mode, is formatted as follows:

Control Field

Data Field

Bus Data

Start

# of

Contr

Time Stamp

# of

Arbitration

# of

Check

of

Control

Byte

4 Bytes

Data

Field

Data

Up to 8 Bytes

sum

Frame

bytes

Bytes

Bytes

in

Message

01

05

02

msb

lsb

ZZ

Y1

Y2

Y3

Y4

0X

The message starts with 01. The number of control bytes is 05. Next is the control byte 02, followed by the time stamp, four bytes, with msb first. The number of data bytes is the number of bytes to follow excluding itself and the checksum byte. Next is a four byte that contains the arbitration field. J1939 divides this field for different functions show in the chart below. The number of data bytes sent by the bus is next. This will be a value between 0 and 8. Next is the bus data followed by the checksum byte.

Arbitration Field (Y1, Y2, Y3, Y4)

The first byte Y1 contains the most significant bits in the J1939 arbitration field. It is followed by Y2, Y3 and Y4. J1939 assigns different function to the arbitration field that must be observed by the user. There is a work sheet included on page 33 to help set up this field.

Arbitration Byte	Y1								Y2								Y3								Y4
Arbitration Bit	7	6	5	4	3	2	1	0	7	6	5	4	3	2	1	0	7	6	5	4	3	2	1	0	7	6	5	4	3	2	1	0
J1939 Arbitration Field	29	28	27	26					252423222120191817161514131211109													8	7	6	5	4	3	2	1
Bit Position
J1939 Function	Priority			R	D	PDU Format								PDU Specific								Source Address
	bits				P

HDV100A3 Command & Response Manual-1306cr 21

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