Using The Data Link Instructions - Mitsubishi Electric Melsec Q Series User Manual

4 WHEN THE Q/LCPU ACCESSES THE PROGRAMMABLE CONTROLLER
OF ANOTHER STATION USING THE DATA LINK INSTRUCTION

4.3 Using the Data Link Instructions

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This section explains how to use the data link instructions when accessing other
stations via the Ethernet module.
(1) SEND instruction
1) When performing simultaneous other station accesses from multiple
communication request source stations to the same communication
request destination station, change the channel number of the
communication request destination station for each communication
request source station.
If the channel number is being used at the communication request
source station (being accessed from other station using the same
channel number) when other station is accessed, the data link
instruction ends in error. So, re-execute the instruction.
If the channel number used is different at the communication request
destination station side, simultaneous other station access can be
performed from a maximum of eight communication request source
stations to the same station.
2) When performing other station access from the same communication
request source station to the same communication request destination
station, change the channel number at the communication request
destination station side.
When designating the same channel number on the communication
request destination station side, perform the second other station
access after the first other station access is complete. If the second
SEND instruction is executed before the first SEND instruction is
completed, the SEND instruction ends in error.
(2) Instruction other than the SEND instruction
1) When simultaneous other station access is performed to the same
communication request destination station from multiple communication
request source station, and a busy error (being accessed from other
station) occurs, re-execute the instruction.
2) When accessing other station from the same communication request
source station to the same communication request destination station,
execute the second data link command after other station access by
the first data link instruction is complete.
(3) Broadcast (Simultaneous broadcast)
When FF is designated as the target station number in the control data when
H
executing SEND/WRITE (SWRITE)/REQ on the Ethernet, the command is sent
to all external devices on the network.
MELSEC-Q/L
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