ELM327DSC(2007) 查看數據表（PDF） - Elm Electronics
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ELM327DSC Datasheet PDF : 51 Pages
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ELM327
AT Commands (continued)
DM1
[ monitor for DM1s ]
The SAE J1939 Protocol broadcasts trouble codes
periodically as they are detected, using Diagnostic
Mode 1 (DM1) messages. This command sets the
ELM327 to continually monitor for this type of
message for you, following multi-segment transport
protocols as required. Note that a combination of
masks and filters could be set to provide a similar
output, but they would not allow multiline messages to
be detected. The DM1 command adds the extra logic
needed for multiline messages.
This command is only available when a CAN
Protocol (A, B, or C) has been selected for J1939
formatting. It returns an error if attempted under any
other conditions.
DP
[ Describe the current Protocol ]
The ELM327 is capable of automatically
determining the appropriate OBD protocol to use for
each vehicle that it is connected to. When the IC
connects to a vehicle, however, it returns only the data
requested, and does not report the protocol found. The
DP command is used to determine the current protocol
that the ELM327 is selected for (even if not
connected). If the automatic option is also selected,
the protocol will show the word "AUTO" before it,
followed by the type. Note that the actual protocol
names are displayed, not the numbers used by the
protocol setting commands.
DPN
[ Describe the Protocol by Number ]
This command is similar to the DP command, but
it returns a number which represents the current
protocol. If the automatic search function is also
enabled, the number will be preceded with the letter
‘A’. The number is the same one that is used with the
set protocol and test protocol commands.
FC SM h
[ Flow Control Set Mode to h ]
This command sets how the ELM327 responds to
First Frame messages when automatic Flow Control
responses are enabled. The single digit provided can
either be ‘0’ (the default) for fully automatic responses,
‘1’ for completely user defined responses, or ‘2’ for
user defined data bytes in the response. More
complete details and examples can be found in the
Altering Flow Control Messages section.
FC SH hhh
[ Flow Control Set Header to… ]
The header (or more properly ‘CAN ID’) bytes
used for CAN Flow Control response messages can
be set using this command. Only the right-most 11 bits
of those provided will be used - the most significant bit
is always removed. This command currently only
affects Flow Control mode 1.
FC SH hhhhhhhh [ Flow Control Set Header to… ]
This command is used to set the header (or ‘CAN
ID’) bits for Flow Control responses with 29 bit CAN ID
systems. Since the 8 nibbles define 32 bits, only the
right-most 29 bits of those provided will be used - the
most significant three bits are always removed. This
command currently only affects Flow Control mode 1.
FC SD [1-5 bytes] [ Flow Control Set Data to… ]
The data bytes that are sent in a CAN Flow
Control message can be set with this command. The
current version of the software allows one to five data
bytes to be defined, with the remainder of the data
bytes in the message being automatically set to the
default CAN filler byte. Data provided with this
command is only used when Flow Control modes 1 or
2 have been enabled.
E0 and E1
[ Echo off (0) or on(1) ]
These commands control whether or not
characters received on the RS232 port are
retransmitted (or echoed) back to the host computer.
To reduce traffic on the RS232 bus, users may wish to
turn echoing off by issuing ATE0. The default is E1 (or
echo on).
H0 and H1
[ Headers off (0) or on(1) ]
These commands control whether or not the
additional (header) bytes of information are shown in
the responses from the vehicle. These are normally
not shown by the ELM327, but can be turned on by
issuing the AT H1 command.
Turning the headers on actually shows more than
just the header bytes – you will see the complete
message as transmitted, including the check-digits and
ELM327DSC
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