B&B Electronics Command Response Protocol HVD100A3 - Manual (Page 8)

4 HDV100A3 Command & Response Manual-1306cr
B&B Electronics -- 707 Dayton Rd. -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 433-5104
Detailed Description of General Function Codes
Command Acknowledgement
All commands sent to the device will be acknowledged. If no error occurs an
ACK will be sent with the ID byte that accompanied the command. If an
error occurred, a NACK will be sent with the ID byte that accompanied the
command as well as a Function code of $05 and the Error Code. The
responses will not be shown for each command since it is the same for
almost all commands. Below is the format of the ACK/NACK response. If
an ACK/NACK response is different for a particular command, it will be
specified.
ACK/NACK Format:
Byte
Number
Byte
Value Function
1 01 Start of frame
2 01 or 03 Number of control bytes = 1 for ACK, 3 for NACK
3 aa ID byte 08 = internal command
4 bb Function code 02 = send time stamp
5 cc
6 00 Number data bytes
7 CS Checksum
aa – ID Byte
$01 = J1708 Interface
$02 = J1939 Interface
$05 = Device Id
$08 = RS-232 Interface
$09 = Message Xmit OK Response
bb – FC Byte
None = Command Received and Valid
$05 = A error was detected, NACK
cc – CD Byte
None = No Error Condition
Error Code = See Section 5.10