J1939 Interface Description; J1939 Message Format; Interpretation Of The Can Identifier - Pepperl+Fuchs IMU360D-F99-B20 Manual

F99 Fusion Inertial Measurement Unit IMU360D-F99-B20

J1939 Interface Description

5 J1939 Interface Description
5.1

J1939 Message Format

The J1939 interface uses the 29 bit CAN-ID. The CAN-ID in J1939 is assembled of a
Parameter Group Number (PGN) and a source address.
A parameter group (PG) consists of various parameters, such as offset value, direction of
rotation, etc. That means, a PGN specifies what's in that data field.
The priority field has a width of 3 bits. It indicates the message priority. Priority "0" is the highest
and "7" the lowest.
A value of "PDU format" between 0x00 and 0xF0 causes messaging between two specific
devices. In this case the field "PDU specific" equates to the destination address. A value of
"PDU format" higher than 0xF0 causes broadcast messaging to all devices in a group. "PDU
specific" is then interpreted as a "group extension".
The device address (node ID) of every individual device in the network has to be unique. This
can be assured by means of the address claiming procedure. Details see chapter "J1939
Interface Description", section "Address claiming".
5.2

Interpretation of the CAN Identifier

The CAN identifier of a J1939 message contains Parameter Group Number (PGN), source
address, priority, data page bit, extended data page bit and a target address (except for
broadcast messages).
The identifier is composed as follows:
Priority
3 bit
Table 5.1
The entire telegram contains the identifier and the data section.
Example Request PGN
Identifier (29 Bit)
Priority
(3 bit)
Extended Data
data page page 
(1 bit) (1 bit)
0x07 0x00 0x00
Table 5.2
Extended data
page Data page
1 bit 1 bit
PGN
PDU format Destination
(8 Bit) address
(8 bit)
0xEA 0x80
0x1CEA8032
PDU Specific
PDU format (Destination address)
8 bit 8 bit
Data Bytes
Source 1 2 3
address
Requested PGN
(8 bit)
0x32 LSB MSB 00 xx xx xx xx xx
Source
address
8 bit
4 5 6 7 8
19