Method and apparatus for calculating the maximum displacement of a rotating shaft

A digital processing unit for monitoring the vibration of a rotating shaft comprising a computing device having programmable code configured to:

• (A) receive sensor measurements correlating to a current shaft position;
• (B) determine the current distance between the centroid of the rotating shaft and the current shaft position;
• (C) determine a sector in which the current shaft position is located;
• (D) determine whether the current distance is a maximum for that sector, and if greater, store the current shaft position as the new stored maximum position for that sector and store the current distance as the new stored maximum distance for that sector;
• (E) repeat steps (A)-(D) for a predetermined period of time;
• (F) calculate, after the predetermined period of time, the maximum displacement between the stored maximum positions, which represents the maximum shaft displacement peak to peak;
• and
• (G) output the maximum displacement peak to peak value to a visual display or computerized shaft controller.