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Friends,
My English is not proper so Please understand the problem & help me.
I have serious problem in networking. My Existing system (DATA-Concentrator) works on RS-422 Modbus RTU. I want to connect one MODICON Quantum PLC on same cable from DCS. I change RS-422 to RS-232 & RS-232 to RS-485 so I can now multidrop. Again I had convert RS-485 to RS-232 for PLC & RS-485 to RS-232 & RS-232 (Cross cable)to RS-422 to Data Concentrator.
Now Problem starts when I give query to Data Concentrator (Existing system). It is responding in proper way as desired, but when I give query to PLC I am not getting response. Address of both system are diffrent. I check that when I remove RS-422 Link PLC starts responding & on connecting RS-422 link it does not work.
One more observation that on issuing query to PLC my Data concentrator TXDA & RXDA LED blinks & also responds. I had changed address of both systems but same problem persists.
Please help.
My English is not proper so Please understand the problem & help me.
I have serious problem in networking. My Existing system (DATA-Concentrator) works on RS-422 Modbus RTU. I want to connect one MODICON Quantum PLC on same cable from DCS. I change RS-422 to RS-232 & RS-232 to RS-485 so I can now multidrop. Again I had convert RS-485 to RS-232 for PLC & RS-485 to RS-232 & RS-232 (Cross cable)to RS-422 to Data Concentrator.
Now Problem starts when I give query to Data Concentrator (Existing system). It is responding in proper way as desired, but when I give query to PLC I am not getting response. Address of both system are diffrent. I check that when I remove RS-422 Link PLC starts responding & on connecting RS-422 link it does not work.
One more observation that on issuing query to PLC my Data concentrator TXDA & RXDA LED blinks & also responds. I had changed address of both systems but same problem persists.
Please help.
