14
8. CAN-Bus Messages
The C220 Controller is inter-operable with a SAE J1939 CAN network for
reading the gross vehicle weight from an Air-Weigh
®
LoadMaxx™ on-board weigh scale.
This section describes the J1939 message formats used by the C220 Controller.
8.1. J1939 Address Claim and Name Field
Upon power-up, the C220 Controller issues a J1939 Address-Claim PDU message
to inform the network of its J1939 Name and Preferred Address. A J1939 Address Claim
message is sent with priority = 6, PF = 238, DA = 255, SA = 113 (the Preferred Address),
and 64 bits of Name information formatted as follows:
Table 5
C220 Controller J1939 Name
Field
Bits Value
Arbitrary Address Capable
1
0
Industry Group
3
0
Vehicle Systems Instance
4
0
Vehicle System
7
0
Reserved
1
0
Function
8
52
Function Instance
5
0
ECU Instance
3
0
Manufacturer Code
11
689 (Aarcomm Systems Inc.); this may be
overridden; contact Aarcomm for more
information.
Identity Number
21
The lowest 21 bits of the 28-bit radio key
(labelled in hexadecimal on the back of the
C220 Controller).
The C220 Controller has a default Preferred Address of 113 (71 hexadecimal),
and is not arbitrary-address capable. If the C220 Controller detects it has lost the address-
claim process, it will not send any further messages on the CAN bus. In case of an
address conflict, please contact Aarcomm for instructions on how to configure the C220
Controller for a different Preferred Address.
