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7 Layer 2 Communication Mode (11/29 bit ID)
7.2 [BFM #1100 to #1267] Pre-defined Layer 2 Messages Parameter
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FX
3U
-J1939 User's Manual
1
Introduc
tion
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Specifi
cations
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Inst
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Wi
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Al
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Buf
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Memor
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J1939 C
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Mode
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La
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C
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M
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PL
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Co
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Comm
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Proc
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7.2.1
Pre-defined Layer 2 transmit messages
This subsection describes parameters A to D for the transmit message.
1. Parameter A and B for each Layer 2 message
A message buffer in BFM #100 to #393 is assigned to a Layer 2 transmit message by writing HFFFF in
parameter A, and writing H7FFF, H6FFF or H5FFF in parameter B.
For unused Layer 2 messages, set parameter A and B to HFFFF.
Note
The Layer 2 implementation of the FX
3U
-J1939 can handle up to 28 transmit messages with RTR handling
(parameter B = H7FFF or H6FFF). If the configuration violates this rule, the first 28 transmit message
configurations remain as they are, and RTR handling is disabled for any further transmit messages as
parameter B is forced to H5FFF.
For Layer 2 RTR flags, refer to Section 7.3
• When using the auto RTR response
Set H7FFF to parameter B for the Layer 2 message.
The FX
3U
-J1939 automatically responds to Remote Transmit Requests (RTRs) if the 11/29 bit CAN-ID
(e.g. setting in BFM #100 and #101) matches the ID in the RTR message.
Reception of the RTR message is not displayed in the Layer 2 RTR Flags.
For Layer 2 RTR flags, refer to Section 7.3
• When using the manual RTR response
Set H6FFF to parameter B for the Layer 2 message.
The FX
3U
-J1939 will not automatically respond to Remote Transmit Requests, but the reception of the
RTR message is displayed by the Layer 2 RTR Flag.
For Layer 2 RTR flags, refer to Section 7.3
• When using the disable RTR handling
Set H5FFF to parameter B for the Layer 2 message.
The FX
3U
-J1939 will discard any incoming RTR telegrams matching the CAN-ID of this Layer 2 message.
Parameter
Description
Default Value
Layer 2 message number parameter A
Constant HFFFF
HFFFF
Layer 2 message number parameter B
H7FFF (auto RTR response)
H6FFF (manual RTR response)
H5FFF (disable RTR handling)
HFFFF (message disabled)
HFFFF
Layer 2 message number parameter C
Transmission type
H0000
Layer 2 message number parameter D
Cycle time in [10 ms]
H0000