When you calibrate the hydraulics or the hydrostats, it sets a threshold (in milliamps) in the controller when things start to move. It also learns the milliamps for things like turtle travel speed and rabbit travel speed in the hydrostats. Another thing it learns is maximum lever travel in all directions. So, every time you go to boom up, the controller starts immediately at that threshold to move a function, then ramps up from there. So, lets say it takes 50 mA's to move the boom up. Over time when things wear, spools may start moving easier, so when the controller commands that 50 mA's to start the boom up, the boom may now start to move up at 40 mA's, which may now be a hard jerk of a start (hence the complaint of jerkiness). Re-calibration resets those values to allow for the wear. We recommend re-calibrating every 500 - 1000 hrs, depending on the machine.
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