B&B Electronics manual Message Transmission sending data to the 1939STB

Page 36

Message Transmission (sending data to the 1939STB)

The transmission window is divided into three rows. The first row is the internal header information. The second row contains message control information. The third row is the data payload sent with the information.

The first row has 4 bytes. Bytes 1 and 2 are set to 8 and 21 hex. All data is entered in hex. The next two bytes, 3 and 4, are set by the user. Refer to pages 6 and 7 of this manual for help setting theses two bytes. Setting a byte is done by clicking in the box under the label and entering the proper hex value. All values in this row must contain information or the message will be rejected.

The second row contains bytes 5 though 11. These bytes are set by the user. All values are entered in hex. All of the bytes in this row do NOT have to contain data for the message to be accepted.

The last row is the data payload that is transmitted with an SAE-

J1939 message. This row may contain data or left blank.

Message Reception

To receive information from the SAE-J1939 bus, the user must program the 1939STB to receive a message. This is done by first sending a receive message to the 1939STB. Page 18 explains how to configure a message to receive data. After the proper byte codes are entered into the 1939STB, the device “listens” on the SAE-J1939 bus for a message that matches the identity code of the reception message. The message header information and data are displayed in the lower window. The incoming data will fill in the slots from top to bottom. Once the data moves off the page it is lost. If a permanent copy of the data is needed use “Data Logging”.

NOTE: MicroSoft Visual Basic only allows a buffer of approximately 3K. You must manually clear the Receive Message buffer or you will get a buffer overflow error.

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1939STB4600 Manual

 

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

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Contents RS-232 to J1939 Converter CE Model 1939STBTable of Contents Introduction SAE Publications1939STB4600 Manual Description Electrical Specification Physical DescriptionCommunication directed to the device Format Control Byte Byte 3 NibbleByte Vendor String Setup Internal FunctionsVendor String Message Received from the SAE-J1939 BusBaud Rate Setup RS-232 Baud ChangeRS-232 Baud Rate Change cont’d Parity Setup Byte 5 UB3Stop Bit Setup Word LengthExternal Commands J1939 FormatMessage Header Setup Valid Codes for ByteMessage Information J1939 Message Information Two Bit Values for Byte 5Byte IntpndTransmit XTD Bit2 DLC DIRSAE-J1939 Control Header J1939 Message Frame1939STB4600 Manual Byte Shown in Table1939STB4600 Manual Byte 1939STB4600 Manual Bytes 9 1939STB4600 Manual DLC Data Length Code DIR Message DirectionData Field Reception of Data SAE-J1939 BusID Byte Function Internal Messages Installation Software1939STB4600 Manual Message Transmission sending data to the 1939STB Saving Message Information File LoggingAppendix A. The Extended can / SAE-J1939 Message Frame Arbitration Field Appendix B. Example
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