Can Ignition “talk to” Arduino boards?
Take a look at this thread.
I have had Ignition working with Arduinos,
Using a Ethernet shield I’ve used the Modbus TCP library look here. http://www.biemmeitalia.net/blog/arduino-android-communication-modbus-tcp/. No luck with using a Wi-Fi shield with this yet. We found that it was better to use two processors, one for the data collection and one for Modbus.
Using a Wi-Fi shield we used the Arduino as a data collector and web server and then read the web page using system.net.httpGet and parse the results as floats write to tags. We connected this to strain gauges and an amplifier and this has made a very good torque transducer on a rotating shaft (cheap too).