Raspberry Pi and Arduino on Modbus TCP

I have been looking into Codesys on Raspberry PI It seem to me the weakness of Raspberry PI is I/O and that is the strength of Arduino. So I am using the 2 to build a small system. You can program the Raspberry in Ladder Logic and then have it read / write the Arduino on modbus tcp. You just have to map the I/O in the Arduino to modbus memory locations. Codesys can also have a web page to show the I/O status .Codesys has released a runtime for the PI. What is needed is I/O and this is where Ardunio seems have the lead. Codesys software to build the project runs on windows 32 and is free. The runtime is $45.00 for the Raspberry and is supposed to be released in April 2014, you can download a demo copy now which runs for 2 hours. It does support Modbus TCP and others such as Can bus.

I have downloaded the development package and ran into a problem with the Modbus TCP library not being installed. I contacted Codesys and got thing working. I am using the Arduino for I/O. pretty nice stuff.!!