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5.3 MEWTOCOL-COM Master Communication (SEND)
5.3 MEWTOCOL-COM Master Communication (SEND)
5.3.1 Writing Data to External Device
■
Procedure
PLC has the transmission right in master communication, and master communication is
performed by sending commands to, and receiving responses from, devices that support
MEWTOCOL. Data can be written by specifying unit numbers and memory addresses and
executing F145 (SEND) instruction in a user program, because PLC automatically creates
messages according to the protocol.
PLC
DT100
100
DT101
0
・・・・・・
・・・・・・・・
・・・・・・
・・・・・・・・
■
Sample program
● Send a command from COM1 port of the unit, and write the content of the data registers
DT100 to DT101 of PLC into the data areas DT400 to DT401 of an external device (unit No.
1).
● Confirm that transmission is not in progress (SEND / RECV instruction execution flag
R913C: ON) for the same port, and start up SEND instruction.
● F145 (SEND) instruction is executed by specifying the transfer method (word transfer / bit
transfer), the number of words, unit number of a destination unit, starting address, and the
starting address of PLC memory area that stores data to be transferred. Also specify the bit
Nos. of both sides in the case of bit transfer.
R0
R10
R913C
⑤
(Note 1)
The slave side may not be able to respond, when the scan time of PLC as a master unit is short and
interval between transmission sessions is short. In such cases, insert a timer instruction into the
execution conditions for instructions, and make the sending interval longer.
5-6
Command messages
%01#WDD004000040164000000 (BCC) C
%01$WD (BCC) C
Response messages
Perform writing by specifying Unit number and
address using the SEND instruction
F145 SEND
DT10
④
support MEWTOCOL-COM
R
DT00400 100
DT00401 0
・・・・・・
R
・・・・・・
F0 MV
H2
DT10
①
④
F0 MV
H1001
DT11
②
③
④
DT100
DT0
K400
⑥
⑦
External devices that
・・・・・・・・
・・・・・・・・
Specification of the
transfer method and the
number of transfer words
Specification of the COM
port number of a master
unit
Execution of SEND
instruction
WUME-FPXHCOMG-02
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