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V430 to Omron MX2 MODBUS RTU Problem

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  I have a problem communicating to an Omron MX2 VFD using RS485 MOBUS with a V430.


Basically I have all of the required FB's for MODBUS Serial.  The port is configured, the MODBUS protocol is confured, the drive is configured.  I can monitor the queries and responses on the HMI in Config mode and see that the data is exactly as is should be.  I can also see the data change in the drive parameters.

The problem I have is that in Visilogic, I never see the data from the queries.  For instance, I will execute a Read Coil (Function #1).  I have all the correct parameters set.  The actual data monitored on the HMI shows the data as I expect it to be (at least 1 coil is high).  But in my logic, I never see the data on the output side of the FB.  I also see the total sessions increment by one every time it is executed, but the Acknowledgment number never changes (it's always been 0).  I also never see anything other than 0 for the status (which indicates no problems).  I don't understand what I might be missing and any insight would be helpful.





  Omron 3G3MX2 Inverter



  V430:  Node 1, Comm 1, RS485, 57600, 8, n, 1 - Termination set

  MX2:  Node 2, 57600, 8, n, 1 - Termination set


(this is the test setup.  Eventually there will be more drives attached to the system hence the need for RS485)


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