The ProNav Gen 2 compass is self-calibrating. You only need to calibrate it if MarkSetBot Support tells you to. Here is how to do the hard cal:
NOTE: Make sure the area you are calibrating in his flat and free of compass interference. Do this with a hand-held compass and verify the compass doesn't jump around as you walk an area. Grassy areas are usually a safe bet. This process cannot be done on an incline because the accelerometer and gyroscope are also calibrated during this process.
NOTE 2: Make sure you don't have anything metal on you while you are doing this process. Most likely problems are watches, rings, buttons on coats, and car keys.
Hard cal when installed in motor head:
Hard Cal when not installed in motor head: