B&B Electronics Command Response Protocol HVD100A3 Uživatelský manuál stáhnout pdf (Strana 17)

HDV100A3 Command & Response Manual 13 Cover Page

B&B Electronics -- 707 Dayton Rd. -- PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 -- FAX (815) 433-5104

Below is an example of a vehicle message:

Byte

Number

Byte Value

(hex)

Byte Function

Start of Frame

# of Control Bytes

Control Byte

Timestamp

# of Data Bytes

MID

PID

Data

PID

Data

J1587 Checksum (2’s Compliment)

Message Checksum

PIDs with a range of 0 – 127 and 256 – 383 will return 1 data byte.

PIDs with a range of 128 – 191 and 384 – 447 will return 2 data bytes.

PIDs with a range of 192 – 253 and 448 – 509 will return variable data bytes.

For further description of MIDs and PIDs refer to SAEJ1587 document.

To stop receiving data from the J1708 bus send the following command to

the HDV100A3.

Byte

number

Byte value

(hex)

Byte Function

Start of frame

The number of control bytes

ID byte 01= J1708

Function code 10 hex stop receive

Number of data bytes (00 place holder)

Checksum (bytes 1 through 5 added together)

After sending this command to the device, the device will respond

with a confirmation message and data will cease. Note that there is the

possibility of an incomplete message being sent to the PC after sending this

command. Use the check-sum to verify all messages.

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B&B Electronics Command Response Protocol HVD100A3 Uživatelský manuál Strana 17