Chapter 8 CAN Bus
CPT7 and CPT7700 Installation and Operation User Manual v12
125
8.2.5 Address Claim Procedure
To become operational on the CAN bus, an OEM7 receiver must claim a J1939 address. The preferred
address and a range of alternative addresses are specified using the
J1939CONFIG
command. When a
configured receiver is placed
on bus
, it may make multiple attempts to claim an address. It may also have its
address bumped by a higher priority device claiming the same address.
While the device is attempting to claim an address, the
J1939STATUS
log reports a status of
CLAIMING
and
automatically tries to claim the next allowed address. Depending on the
J1939CONFIG
parameters, an
address different from the
J1939CONFIG
preferred address
may be claimed or the address claim procedure
can fail entirely. If no addresses could be claimed, a
FAILED
status is reported and the receiver takes no
further action. To recover from this failure, take the receiver
off bus
using the
CANCONFIG
command and
change the CAN address configuration using the
J1939CONFIG
command.
The address can also be assigned using J1939
Commanded Address
message sent by another ECU on the
bus, such as a tester unit. The commanded address always overrides the address specified using
J1939CONFIG
command. When the
Commanded Address
is received, the receiver reports a status of
CLAIMING
followed by
CLAIMED
. Restarting CAN using the
J1939CONFIG
command or
CANCONFIG
command clears the commanded address; the Address Claim procedure will be executed again based on
parameters specified in the
J1939CONFIG
command.
8.3 NMEA2000 Logging
OEM7 receivers support both a subset of the standard NMEA2000 PGNs, as well as NovAtel proprietary
PGNs.
All NMEA2000 logs are configured using the
LOG
command, where the COM port is a CAN port (CCOM). The
CCOM port must be associated with a J1939 node using the
CCOMCONFIG
command. If only NMEA2000
logs are needed,
CCOMCONFIG
parameters other than J1939NODE may be ignored.
To enable NMEA2000 logs:
1. Configure the CAN bus. See
2. Enable the CCOM port on the CAN bus node using the
CCOMCONFIG
command.
3. Enable the desired NMEA2000 logs.
NMEA2000 logs can be requested regardless of the on/off bus status of the receiver or the J1939
configuration. They are output if and only if the receiver is online.
The position for the
PGN129025
,
PGN129027
and
PGN129029
logs are reported in the user selected
datum. See the
OUTPUTDATUM
command for more details.
When the solution type is INS (SPAN models), the DOPs in the PGN129029 message are calculated
at a 1 Hz rate.
To determine if the receiver is providing an INS solution, check the
pos type
field in the
BESTPOS
log.
8.3.1 Example of NMEA2000 Log Configuration
1.
CCOMCONFIG CCOM1 NODE1 NMEA2000
2.
LOG CCOM1 PGN129025 ONTIME 0.5
