5 Allocation of Buffer Memories
5.3 [BFM #20] Data Exchange Control
35
FX
3U
-J1939 User's Manual
1
Introduc
tion
2
Specifi
cations
3
Inst
allati
on
4
Wi
rin
g
5
Al
lo
ca
tion of
Buf
fer
Memor
ies
6
J1939 C
omms
Mode
7
La
ye
r 2
C
omm
uni
cation
M
ode
8
PL
C RUN>
S
TOP
Me
ssag
es
9
Co
mmand
Interface
10
Comm
uni
cation
Setti
ngs
Proc
edure
5.3
[BFM #20] Data Exchange Control
This flag is used when data consistency is required for data exchange between data area in BFM #100 to
#399 and BFM #1300 to #1799.
5.4
[BFM #21] Function Mode
Sets up function mode of FX
3U
-J1939. FX
3U
-J1939 chooses a communication mode based on the function
mode set in BFM #21.
Caution
A new valid value written to BFM #21, #24, #25 bit 2, #26, #27 is automatically written to flash ROM.
The maximum number of writes to the built-in flash ROM is 10,000 times.
Therefore, when creating a program, do not frequently write to such buffer memories.
Note
• A change of the function mode requires a restart of the FX
3U
-J1939 to become effective.
For module restart, refer to Section 5.7
Bit
Description
Bit 0
Data consistency flag;
To keep data consistency over a certain data area in BFM #100 to #399 and BFM #1300 to #1799, write all data required to
be treated consistent to the data BFMs and then set the "Data consistency flag" afterwards. The flag is reset automatically.
Bit 1 to 15 Not used
Set Value
Function Mode
K11
Layer 2 communication (11 bit ID) mode
K29
Layer 2 communication (29 bit ID) mode
K1939 (default)
J1939 communication mode
Other value
Setting prohibited
If setting other values, FX
3U
-J1939 keeps the former value.
