·
Length based mappings find every variable (or constant) by position and length
within the CAN message. If length based mappings are less than 8 bytes long their
variables or constants can be placed at any position. If they should be longer the
variables and constants have to be byte aligned.
·
Delimiter based mappings look for a dedicated separator character placed between
the variables and find the variable based on count of these delimiters. Delimiter
based mappings are typically bigger than one CAN message and have to be byte
aligned. If a string variable is mapped the value is fully written to the variable even if it
should be longer than the length defined for the variable.
Delimiter
Only gets enabled if "Delimiter" is chosen in "Mapping Variable Type" above. Then you can
set the separator char to be found in the message.
Receive from / Transmit to
For receive mappings/PGNs: Select the ECU who has to send the PGN where the variable
should be extracted. "Any ECU" is a wildcard meaning "don't care for the source address
and accept this PGN from anyone".
For transmit mappings this property describes the destination address to be used in the
PGN. Please note that some PGNs are broadcasts by definition so that this property will be
ignored for them. See also message format .
Little Endian
J1939 values are transferred least significant byte first (little endian) by default. Since some
manufacturers opt for big endian format in their proprietary J1939 messages you can
configure this here for the whole mapping. If you should have a PGN which contains both
types you have to create two separate mappings.
This setting only applies to numeric values. Strings are expected to be "big endian" i.e. the
first byte of the word or sentence is the first one on the bus.
Mapping Length
Enter the data length of the message you want to configure. The length has to be between 0
and 1785 bytes. Between 0 and 8 bytes, the data length of the mapping and the incoming
message are compared. Only if they match, the data will be put into the mapped variables.
Object Status
With Object Status Active the mapping is working, i.e. it is processing received messages
or sending them. With Object Status Inactive the mapping is not working. This property can
be switched at run time with the setProperty JavaScript function to enable / disable CAN
mappings.
PGN
Enter the PGN number in decimal of hexadecimal format (starting with "0x"). The value will
anyways be displayed in hexadecimal format. In our example PGN 65262 is displayed as
0xFEEE.
PGN Priority
For receive mappings this is ignored. For transmit mappings this priority is used when
sending the message. Priority can be any value between 0 (highest) and 7 (lowest). See
also message format .
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