B&B Electronics RS-232 to J1939 Converter CE 1939STB Benutzerhandbuch
1939STB4600 Manual
9
B&B Electronics Mfg Co Inc – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Commercial Park – Oranmore, Galway, Ireland – Ph +353 91 792444 – Fax +353 91 792445
RS-232 Baud Change
Setting byte-3/nibble-2 to 2 and byte-4/nibble-1 to 2 causes the 1939STB
to change baud. This function also requires 3 bytes of additional information
bytes 5, 6, and 7. It is important to note that after a baud change the PC must
have its baud changed to match the baud of the 1939STB for communication
to exist. If communication is lost after a baud change and cannot be
recovered, disconnecting the 1939STB from its power source will restore the
1939STB to its default baud rate of 9600 baud, 1 stop bit, 8 data bits, no
parity.
bytes 5, 6, and 7. It is important to note that after a baud change the PC must
have its baud changed to match the baud of the 1939STB for communication
to exist. If communication is lost after a baud change and cannot be
recovered, disconnecting the 1939STB from its power source will restore the
1939STB to its default baud rate of 9600 baud, 1 stop bit, 8 data bits, no
parity.
Table 11. Baud Rate Setup
Byte 3
Byte 4
Byte 5
Byte 6
Byte 7
Byte
1
1
Byte
2
2
Nibble 2
Nibble 1
Nibble 2
Nibble 1
UB3
Baud 1
Baud 2
81
21
0010 0011
0000
0010
81
21
23 hex
02 hex
03 hex
00 hex
06 hex
Table 11 shows how an internal command is used to set the 1939STB to a
baud rate of 300, 1 stop bit, 8 data words, and no parity. Byte 3 nibble 2 sets
the internal command function. A nibble value of 2 sets the J1939STB into
the Internal Function mode. Nibble 1 of byte 3 tells the 1939STB 3 bytes will
follow Byte 4. Byte 4, nibble 1 is set to 2 telling the 1939STB to perform a
baud change using the information contained in bytes 5, 6, and 7.
the internal command function. A nibble value of 2 sets the J1939STB into
the Internal Function mode. Nibble 1 of byte 3 tells the 1939STB 3 bytes will
follow Byte 4. Byte 4, nibble 1 is set to 2 telling the 1939STB to perform a
baud change using the information contained in bytes 5, 6, and 7.
Table 12. Baud Rate Setup
Baud Rate
Decimal Divisor
Hex Divisor MSB (Baud 2)
Hex Divisor LSB (Baud 1)
300
1556
06 hex
00 hex
1200
384
01 hex
80 hex
2400
192
00 hex
C0 hex
9600
48
00 hex *
30 hex *
19200
24
00 hex
18 hex
38,400
12
00 hex
0C hex
57,600
8
00 hex
08 hex
* Setup default value.