UK
Inclination sensor JN
7
7 7 SAE J1939 interface
The inclination sensors have a standardised SAEJ1939 interface. All measured
values and parameter groups can be accessed via the J1939 protocol. The
individual configuration can be saved in the internal permanent memory (flash).
7.1 Overview and structure of the SAE J1939 protocol
The SAE J1939 protocol uses a 29-bit CAN identifier (extended frame format CAN
2.0B). An SAE J1939 message has the following structure:
SAE J1939 message
29-bit CAN identifier
Data
Priority
28…26
PGN
25...8
Source address
7...0
User data of the
message
0…8 bytes
Parameter Group Number (PGN)
Ext. data page 25
Data page 24
PDU format (PF)
23…16
Target address / group
extension (PS) 15…8
PDU format 1 (specific)
00h - EFh
23…16
Target address (DA)
15…8
PDU format 2 (global)
F0h - FFh
23…16
Group Extension (GE)
15…8
7.1.1 PDU format 1
This format defines a message which is sent to a defined unit. In this case the
PDU-specific byte (PS) is the target address (DA) of the unit. If the value of the
PDU format field (PF) is between 0x00 and 0xEF, it is a PDU format 1 message.
For proprietary (manufacturer-specific) messages the PDU format value 0xEF is
defined. Ext. data page bit = 0 and data page bit = 0.
7.1.2 PDU format 2
This format defines a message which is sent globally. In this case the PDU-
specific byte (PS) corresponds to the group extension (GE). If the value of the
PDU format field (PF) is between 0xF0 and 0xFF, it is a PDU format 2 message.
For proprietary (manufacturer-specific) messages the area (PDU format PF) and
group extension (GE) 0xFF00 – 0xFFFF is defined.
Ext. data page bit = 0 and data page bit = 0