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User Manual - QG65N2 SAE J1939 Inclinometer (Type JB) V1.1
7.4.
SPN (Suspect Parameter Number)
SPN is a 19-bit identifier for the CAN signals (parameters) contained in the data. SPNs are grouped by PGNs and can
be described in terms of their bit start position, bit length, scale, offset and unit - information required to extract
and scale the SPN data to physical values.
The assignment of SPNs can be found in SAE J1939-21 documents. DIS sensors B.V. is using PGN 2551 for definition
of inclination and acceleration outputs.
Example – SPN 2551 by PGN 65280 Inclination output defined by DIS Sensors B.V.
PGN
Name
Priority Position
in PG
Bit Size
Resolution
(scale)
Offset Data Range
65280
d
FF00
h
X axis (Longitudinal)
3
0
16
0.01°/bit
-90° - +90°
Y axis (Lateral)
16
16
0.01°/bit
-90° - +90°
7.5.
NAME and ACM (PGN 60928)
Every device shall have one address and an associated
NAME
to communicate on the SAE J1939 network.
SAE J1939 defines a 64-bit NAME to identify the primary function of a controller application. The NAME consists of
fields shown in table below.
MSB 64 bits LSB
1 bit
3 bit
4 bit
7 bit
1 bit
8 bit
5 bit
3 bit
11 bit
21 bit
Arbitrary
Address
Capable
Industry
group
Vehicle
system
Instance
Vehicle
System
Reserved Function Function
Instance
ECU
Instance
Manufacturer
Code
Identify
Number
Table 17 - NAME format
Address Claim
, defined in SAE J1939-81, is the process for claiming a network address and associating the NAME,
or vehicle function, to that address.
Upon power-up or whenever requested, a device must send an ACM to claim an address. Other devices must
compare the newly claimed address with their own to avoid conflicts. When multiple devices claim the same
address, the device with lower NAME value uses the address, the others must claim a different address or stop
communicating on the network.
A device can send request for the ACM to determine whether addresses claimed by other devices. PGN 59904
(RQST) for ACM (PGN 60928) is described as below:
