UMAX180800, 20 Thermocouple, 2 RTD, 4 Inputs, 6 Relays Dual CAN Controller
Version 1
Page: 8-71
ISO/OSI Network Model
Layer
J1939 Standard
Memory access protocol (MAP) support. DM14, DM15, DM16 are used
by EA to program configuration parameters.
DM13 support is provided to temporarily suppress transmission of
application-specific PGNs.
2.3.1 CAN Baud Rate
The controller can operate at J1939 standard 250 and 500 kbit/s baud rates. It can also run at
667kbit/s and 1Mbit/s
– the maximum baud rate supported by the CAN hardware.
The baud rate selection is performed automatically upon connection to the CAN network using
passive and active automatic baud rate detection process described in J1939/16. Once
detected, the baud rate is stored in non-volatile memory and used on the next controller
power-up.
The baud rate detection can be disabled for permanently installed units to maintain the desired
baud rate on the CAN network.
2.3.2 J1939 Name and Address
Before sending and receiving any application data, the converter claims its network address
with a unique J1939 Name. The Name fields are presented in the table below:
Table 2. J1939 Name Fields
Field Name
Field Length
Field Value
Configurable
Arbitrary Address Capable
1 bit
1 (Capable)
No
Industry Group
3 bit
0 (Global)
No
Vehicle System Instance
4 bit
0 (First Instance)
No
Vehicle System
7 bit
0 (Nonspecific System)
No
Reserved
1 bit
0
No
Function
8 bit
126 (IO Controller, Axiomatic
proprietary)
No
Function Instance
5 bit
20 (AX180800, Axiomatic proprietary)
No
ECU Instance
3 bit
0 (First Instance)
Yes
Manufacturer Code
11 bit
162 (Axiomatic Technologies Corp.)
No
Identity Number
21 bit
Calculated on the base of the
microcontroller unique ID
No
The user can change the controller
ECU Instance
using EA to accommodate multiple signal
input controllers on the same CAN network.
The controller takes its network
ECU Address
from a pool of addresses assigned to self-
configurable ECUs. The default address can be changed during an arbitration process or upon
receiving a commanded address message. The new address value will be stored in a non-
volatile memory and used next time for claiming the network address. The
ECU Address
can
also be changed in EA.
