Mewtocol Master Communication (Recv); Read Data From An External Device - Panasonic FP7 CPU Unit User Manual

MEWTOCOL Master/Slave Communication

5.3 MEWTOCOL Master Communication (RECV)

5.3.1 Read Data From an External Device

 Instructions
In master communication, PLC has the sending right, and executes communication by
sending commands to devices that support MEWTOCOL, and receiving responses.
Messages in accordance with the protocol are automatically generated by PLC. In the user
program, reading can be done simply by specifying the station no. and memory address and
executing RECV commands.
PLC
DT100 100
DT101 0
・・・・・・ ・・・・・・・・
・・・・・・ ・・・・・・・・
Note: The above figure indicates the data part of MEWTOCOL-DAT. In communication via LAN, a header including size information of the sent data
is added.
 Sample program
• Send commands from the LAN port of the CPU unit, read data from the data area of an
external device DT400 - DT401, and write the content into PLC's data register DT100 -
DT101.
• Confirm that Connection 1 is established in the master mode (X90), and that the sending
process is not in progress for the same port (Y90), and start up the SEND command.
• In the UNITSEL command, specify the slot No. (LAN port: U100) and the connection No. (U1).
• In the RECV command, specify and execute the partner station no. (U1), initial address
(DT400), No. of data (U2), and initial address on the PLC side to save data (DT100).
X90
R0
DF
（ ）
Clear to send
master
R100 communication flag
RECV.US
5-4
Command message
(Hex) 80 51 09 90 01 02 00
(Hex) 80 D1 FF 64 00 00 00
Response message
Specify and read/write address based on SEND/RECV command
Y90
Sending master
communication flag
UNITSEL
U1 DT400
S1 S2
R100
Execute
RECV
U100 U1
S1 S2
U2 DT100 DT0
n D1 D2
Our PLC supporting
MEWTOCOL-DAT
DT00400 100
DT00401 0
・・・・・・ ・・・・・・・・
・・・・・・ ・・・・・・・・
Starting conditions for RECV
execution
Clear to send flag: ON
Sending flag: OFF
Settings for communication port
S1: CPU LAN port (U100)
S2: Connection 1 (U1)
RECV processing
S1: Partner station no. (U1)
S2: Data address (DT400)
n: No. of data (U2)
D1: Data saving area (DT100)
D2: Execution result code (DT0)