Getting Started Using The K3SC Serial Converter With Multiple PLCs


This helpsheet is aimed at providing a worked example for connecting a PC using CX-Programmer or Compolet/FINS Gateway to more than one Omron PLC using RS422 serial network.


This helpsheet assumes that the user is familiar with Omron Host Link settings and CX-Programmer.  

Diagrammatic overview of worked example
Network assumptions

All PLCs use standard communications settings (9600baud, 7 data, even parity, 2 stop bits).  However, the host link unit numbers (contacts) must be set uniquely (use CX-Programmer, see below).

Connecting from PC to K3SC

Connection on RS422 network from master (K3SC) to slaves (CPM2A + CPM1-CIF11)

Note   The first drop has the cables changed over (Sends to Receives) because the K3SC is attached to the master and the PLC’s are the slaves.  However, all other devices are connected in parallel (Send’s with Sends and Receives to Receives).

Switch settings for K3SC

 All DIP SW settings should be set to off (default host link communications) except DIP SW 9


Switch settings details for other settings than default on K3SC.


Settings for Host Link ports within CPM2A (using CX-Programmer)

Notes      The CPM1-CIF11 connects to the peripheral port, therefore the Host Link Unit address settings must be changed here.


              Don’t forget to make sure that the ‘Default Host Link’ settings DIP SW is set on the CPM2A.  This will invalidate the settings set in the PLC setup area.

Settings for first CPM2A (With Host Link Unit 00)

Settings for second CPM2A (With Host Link Unit 01)

Once the PLC settings have been downloaded to the respective PLCs, then CX-Programmer can be used to communicate to both PLCs upon the RS422 network simultaneously.  Make sure that the settings for communication are set to reflect the Host Link unit addresses set and downloaded above.

Settings within CX-Programmer to communicate to Host Link settings after host link settings changed (above).


CX-Programmer showing PLC instances (2 PLC’s set in the project)

Host Link communication settings for ‘PLC_Host_00’

Host Link communication settings for ‘PLC_Host_01’