GW-7238D J1939 to MBTCP Server / MBRTU Slave Gateway User’s Manual (Ver.1.1, May. 2013) ---
48
Byte 6: Net ID (Station number)
Byte 7: FC=10 (Hex)
Byte 8-9: Reference number
Byte 10-11: Word count
Example:
In the address 40001, write the value in 0x1234.
[Request Command] (Byte0, Byte1... Byten) (Hex)
00 00 00 00 00 09
01 10 00 00 00 01 02
12 34
GW-7238D’s response is OK.
[Response] (Byte0, Byte1... Byten) (Hex)
00 00 00 00 00 06
01 10 00 00 00 01
Get J1939 input data
Using the Modbus command as below:
FC4 Read multiple input registers (3xxxx) for AI
[Request] (Request by Modbus master device)
Byte 0-1
: Transaction Identifier (Usually zero when making a
request)
Byte 2-3
: Protocol Identifier (Protocol number. Must be zero)
Byte 4-5
: Length (Number of following bytes - upper
/
lower
byte)
Byte 6: Net ID (Station number)
Byte 7: FC=04
Byte 8-9: Reference number
Byte 10-11: Word count
[Response] (Response from the GW-7238D)
Byte 0-1
: Transaction Identifier (Usually zero when
making a request)
Byte 2-3
: Protocol Identifier (Protocol number. Must be
zero)
Byte 4-5
: Length (Number of following bytes - upper
/
lower byte)