My group just came out with a 4-20mA shield for the Arduino. You can find the web-page here: http://www.erdosmiller.com/products/arduino-4-20ma-shield
- 4 4-20mA shield inputs. (2-wire,3-wire,4-wire compatible)
- Buffered ADC inputs.
- High resolution external ADC with internal reference.
- Also works with the built in Arduino ADCs.
- There is also a switching regulator on the board so that the Arduino can be powered from 10-36V.
- Use the shield in a "pass-thru" configuration or as a 4-20mA sensor endpoints.