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MELSEC-Q
3 WHEN COMMUNICATING WITH MELSECNET/H, MELSECNET/10
RELAY
3.4 Procedure for Accessing Other Stations
This section explains the procedure for accessing other stations via the Ethernet using the
MELSECNET/H, MELSECNET/10 relay communication function as well as the required
processing.
(1) Setting the parameters
The parameters shown in Section 3.3 must be set using GX Developer.
(2) Accessing other stations
Access to other stations is performed from an external device/local station QCPU
using the MELSECNET/H, MELSECNET/10 relay communication function.
REMARK
• Access to other stations with the MELSECNET/H, MELSECNET/10 relay
communication function is performed using the UDP/IP protocol and data is
always communicated in binary code.
• In the data communication, the port number (for the UDP/IP port) for the
Ethernet module system is used.
• It is possible to continue accessing other stations while the initial normal
completion signal (X19) is on.
When the initial normal completion signal (X19) is turned off, the Ethernet module
forcefully closes the connection although other station is being accessed.
(3) End processing of the Ethernet module
When ending access to other station with the MELSECNET/H, MELSECNET/10
relay communication function that has been made using a connection opened by
user, execute the close processing of the connection by seeing Section 5.6 of the
User's Manual (Basic).
When the following two functions are used to access other station, the close
processing is not required.
• Communication using the data link instructions
• Communication with other stations using GX Developer
3.5 Precautions for Accessing Other Stations
The following describes precautions when accessing other stations via the Ethernet
module using the MELSECNET/H, MELSECNET/10 relay communication function.
(1) The user should make an arrangement so that duplicate Network No.s for
the Ethernet network system that have already been assigned to the
Ethernet modules are not used.
In addition, make sure that the same station numbers for the Ethernet
network system as those already assigned to the existing network system
mentioned above and other Ethernet are not used.
(2) Access to other stations using the MELSECNET/H, MELSECNET/10 relay
communication function is performed using the UDP/IP protocol and data is
always communicated in binary code.
POINT
See the manual for the MELSECNET/H, MELSECNET/10 system for the interlock
signals and the send/receive processing and processing time of the link data when
performing data communication with QCPUs of other stations via the
MELSECNET/H, MELSECNET/10 network system.
