I see that Maretron’s DSM150, DSM200, and DSM250 displays have a SSC200 configuration setting called "Rate of Turn Zero Offset Calibration..."; what is this?

Maretron’s DSM150, DSM200, and DSM250 displays have a SSC200 configuration setting called "Rate of Turn Zero Offset Calibration...", which is used to calibrate the rate of turn gyro found within the SSC200. Rate gyros tend to drift over temperature (i.e., indicate that the vessel is turning all though it isn’t). You use this calibration setting to calibrate the SSC200 rate of turn gyro at several different temperatures (i.e., early winter morning when it is the coldest and late summer afternoon when it is the hottest) to achieve the most accurate readings. It is also beneficial to calibrate the rate of turn gyro if you are experiencing problems performing magnetic deviation calibration a compass.