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MELSEC-Q
4 WHEN THE QCPU ACCESSES THE OTHER STATION PLC USING THE
DATA LINK INSTRUCTION
Instruction
Storage area of execution result
SEND
RECV, RECVS
READ, SREAD
WRITE, SWRITE
REQ
The completion status storage device of the control data storage
device of the instruction used.
ZNRD
Address CF
H
(207)
ZNWR
The execution result storage area
in the buffer memory
Address D1
H
(209)
(4) Clock data when each of the data link instructions ends abnormally
In the clock data stored as control data at the time that each of the data link
instructions ends abnormally (set only when it is something wrong), the year data
(upper 2 digits) is stored only when the QCPU is the error detection station. If the
error detection station is other than the QCPU, 00
H
is stored.
(5) Channels used by the ZNRD and ZNWR instructions
The ZNRD and ZNWR instructions for Ethernet modules are executed using the
following channels of the target Ethernet module.
• ZNRD: Channel 1
• ZNWR: Channel 2
Do not use the channels used by the ZNRD and ZNWR instructions listed above
for other data link instructions in an Ethernet module mounted station that
executes the ZNRD and ZNWR instructions. Also, do not execute data link
instructions from other stations on the channels listed above in an Ethernet
module mounted station that executes the ZNRD and ZNWR instructions.
POINT
(1) See Chapter 3 for details of the following when performing other station access
using the data link instructions.
• The accessible range and accessible stations of the other stations
• Setting to perform other station access
• Other station access procedure
(2) The communication using the data link instructions on the Ethernet is
performed with UDP/IP.
When executing each data link instruction except for ZNRD and ZNWR, it is
recommended to designate a value greater than "1" to the number of retries
setting area of the control data storage device.
(3) See the MELSECNET/H, MELSECNET/10 Reference Manual regarding the
link data send/receive processing and processing time in data communication
with the other station PLC CPU via MELSECNET/H, MELSECNET/10.
(4) For details about data designation methods in the data link instruction, see
Chapter 6.
Содержание QJ71E71-100 Series
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