Panasonic FP7 Series User Manual page 111

Operan
d
W W
X Y
D1 ● ●
D2 ● ●
(Note 1) Only in the case of "direct address specification" (main instruction) in the MODBUS mode, an integer
can be specified for the sender address.
■
Available bit devices (●: Available)
Operand
X
S1
S2 ●
n
D1 ●
D2
■
Outline of operation
● The MODBUS command is sent from the communication port of the unit to send/receive data
to/from 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.
● Specify the MODBUS command and the partner MODBUS address in a Hex format in [S1].
● When the RECV instruction is executed, data are read from the address starting with [S2] in
the partner unit, and stored in the area starting with [D1] in the master unit.
● The transfer method (register transfer/bit transfer) and the MODBUS function code that can
be used vary, depending on the type of device specified by [D1].
● The amount of received 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 [D2].
■
Specification of [S1] and [n]
● Operand [S1] is specified as a combination of a two-digit hexadecimal MODBUS function
code and a two-digit hexadecimal partner station number.
Example: Specify "H030F" in the case of MODBUS function code 03 (read holding registers)
and station number 15.
● The transfer method and the MODBUS function code that can be used vary, depending on
the type of device specified by the operand [D1].
WUME-FP7COM-07
8.3 MODBUS RTU Master Communication (RECV)
16-Bit device:
W W W S D
R L S D T
● ● ●
● ● ●
Bit device
Y R L T C
● ● ●
● ● ●
32-Bit
device:
TS TE
L U W
WI
C C
D M O
S E
●
●
S O
P E IN
R T
Real
Integer numbe
IX K Ｕ H SF
Specification of bit of
word device
DT.n LD.n
● ●
● ●
St
rin
r g Index
modifie
r
D
" "
F
●
●
Index modifier
●
●
8-15