Interfacing Arduino (uno/any other type) with RS485 port

Hi All I'm trying to connect a power meter (see link)to an Arduino to use its power readings to control the operation of a wind turbine. What is the best way to interface the device?

Device documentation link Thanks for your help

There are shields for that:

http://www.cutedigi.com/arduino-shields/rs485-shield-for-arduino.html

If you google “Arduino rs485” you will find other solutions as well. Converting TTL Serial to RS485 requires not much more than a cheap IC and a couple of resistors, but a ready made shield is easier and probably a better solution.