Operan
d
16-Bit device:
32-Bit
device:
Integer
Real
numbe
r
St
rin
g
Index
modifie
r
W
X
W
Y
W
R
W
L
W
S
S
D
D
T
L
D
U
M
WI
W
O
TS
C
S
TE
C
E
IX K Ｕ H SF
D
F
" "
D2 ● ● ● ● ● ● ●
(N
ote
1)
●
D3 ● ● ● ● ● ● ●
(Note 1) When the destination unit is FP7, only global devices can be specified. (Local devices cannot be
specified.)
■
Available bit devices (●: Available)
Operand
Bit device
Specification of bit of
word device
Index
modifier
X Y R L T C P E SR IN OT DT.n LD.n
S ● ● ● ● ● ● ●
n
D1
D2
D3
■
Outline of operation
● The MODBUS command is sent from the communication port of the unit to perform the data
transmission with external devices.
● Data can be read and written by specifying station numbers and memory addresses and
executing the SEND and RECV instructions in a user program, because PLC automatically
creates messages according to the protocol.
● Select a communication mode in the configuration menu of the tool software FPWIN GR7.
● Specify the MODBUS command to be used, and the partner MODBUS station number, in a
Hex format in [D1].
● When the SEND instruction is executed, data are read from the device in the master unit,
starting with [S], and stored in the address starting with [D2] of the partner unit.
● The transfer method (register transfer/bit transfer) and the type of MODBUS command that
can be used vary, depending on the type of device specified by [S] and data amount
specified by [n].
● The amount of sent data [n] is specified in words for the register transfer, and in the number
of bits for the bit transfer.
● The execution result code is stored in the one-word area of the master unit that is specified
by [D3].
■
Specification of [S], [n] and [D1]
● The transfer method and the MODBUS function code that can be used vary, depending on
the type of device specified by the operand [S] and the sent data amount specified by [n].
15.6 SEND (MODBUS Master: Function Code Specification)
15-38 WUME-FP7CPUPGR-12
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