8
When work at this mode, there is no need to write any program in PLC for
operation.
5.1.2 Client Mode
While work at client mode, the Ethernet module will wait the command
message at port4. When it finds the message is for the PLC station
located at remote site(Please refer section 5.3.6 for setting) then it will
pack the message according to the content of port mapping table and
send it to the network. After that, Ethernet module will keep an eye on
network for the reply message. Upon receiving the reply message, the
Ethernet module will decode the message then send back to PLC thru
serial port hence complete a client mode transaction. When work at this
mode, the direct connected single PLC or the master station of PLC LINK
connected by RS485 interface are all operated at master mode, which
means it use LINK instruction mode0 to send the command actively. The
client mode also can be further divided into standard mode and virtual
server mode. Explanation as follows
5.1.2.1 Standard Client Mode
When work at this mode, the master PLC connected with Ethernet module
can use LINK instruction mode0 send the command message to other PLC.
The target PLC that master PLC intend to command can be a local slave
PLC connected by RS485 interface to master PLC or a PLC located at
remote site with sever mode Ethernet connection. There is a “Station to
network address translation table” in the Ethernet module when work at
client mode. This table includes the information about the mapping of
local station and remote station
,
the user should set this table according
to the actual application deployment (Please refer section 5.3.6 for table
setting). While operation, the Ethernet module will constantly inspect the
received message, if the station number in the message can be found in
the translation table that means the message is going to route to network,
the Ethernet module will first replace the station number in message
according to the translation table then re-calculate and update the check
sum of translated message and encapsulate it in network data packet and
finally send it to the network. After received the reply message from
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