The Wide or Narrow Bandpass filter automatically attempts to track the input RPM. This is useful to see how the vibration changes over a wide RPM range. The filter tracks as long as the RPM does not change too quickly. As RPMs change, the phase of the image changes as the filter tracks.
To enable filter tracking, press
The CSI 555 displays "TRACK".
To disable filter tracking, press
The CSI 555 briefly displays "NO TR".