Well, I think the device was pre-calibrated at the factory.
I didn’t go through calibration on mine as I tested it with another compass for comparison and it was right on the money.
But, let me know how your’s goes. I have the RP-5 robot base and drove it around with the compass sending data. With and without the motors running I got the same reading.
Right now I am controlling my robot base with a WiFly device and my own software. I use TeraTerm to send commands (f55 - Forward 55%, r40 - Right Turn 40%, etc). It works great controlling it from my WiFi network and PC. I am in the process of writing a function (h125 - turn to a heading of 123 deg) or whatever heading that is entered.