Arduino to ControlLogix

Has anyone had any experience trying to connect an Arduino to ControlLogix? I am trying to use the Digi One IAP box to talk modbus to the arduino and then use a SLC typed read MSG to get the information into the PLC. I am sending the request from the PLC to the Digi One and the arduino is reciving it, however I am not getting any data from the arduino to the digi one to pass on to the PLC.

I have used this same ControlLogix/digi one setup to talk Modbus to other PLC's previously and thought it might be a good way to go since the Arduino can talk modbus/RTU.

I am working on an inexpensive solution to read data from an analog input to the XBee and transmit it back to a ControlLogix PLC.

Any thoughts or suggestions on this would be appreciated.

Thanks
Ian

I never used the Arduino to talk to ControlLogix, but I have used the Raspberry Pi to read/write directly with a CLX using AdvancedHMI.

I have not used the Arduino but you could communicate through Modbus TCP.

http://myarduinoprojects.com/modbus.html

Regards,
Garry
http://www.accautomation.ca