Emerson 2130 RBM Consultant Pro, Справочное руководство

Страница: 206 / 394

3-126 Horizontal Alignment
Reading Up and Down Arrows
Use the Reading Up and Down Arrow keys to scroll through the list of readings one
at a time. These soft keys will wrap around the list. These keys are only active when
more than one reading is listed. The Up and Down Arrow keys can be used to do
the same.
Sweep Mode Curve Data
When using the sweep mode, calculations are completed in the following manner.
If readings were taken from each laser target at 1° intervals (with the position as the
Y- axis and the rotational position as the X-axis), a sine wave would be formed. Even
when only part of the sine wave data is collected, Emerson’s Alignment software can
still curve fit a sine wave to this limited data. Called curve fitting, all values used to
determine the machine moves can be obtained from the completed sine waves.
Emerson recommends you sweep at least 90°; however, accuracy still may be
reduced even at 90°. At the very least, this could result in more machine moves
being required to achieve satisfactory alignment. If data was acquired in a sweep arc
of less than 70°, a warning message will be displayed advising you to retake the data.
If you answer yes, then the data will be discarded and you will be advanced back to
the data acquisition screen. If you answer no, then the data is stored and you
advance to the next step in the procedure.
Each head will store up to 180 readings (the higher the number, the greater the
accuracy), however, all 180 readings are not required to determine the curve fit
sine wave. You must have at least three readings and they should be spaced at large
intervals in the shaft rotation. If too few data points were acquired, a warning mes-
sage displays advising you to retake the data.
After the sweep data has been transferred from the heads to the analyzer, the data
will be automatically curve fit. The quality of the data is shown by the curve fit per-
centage. If more points are located off the sine wave (the greater distance from the
curve), the lower the percentage will be. A high number of points on the curve
mean that most of the data were acquired from points that lay on the sine curve.
Refer to the Data Quality section on page 3-127 for more information.
If the data correlation (curve fit percentage) can not be brought into the accept-
able level, but the peak-peak amplitude of the data is too low, then a message dis-
plays advising you that the machine may be aligned within tolerance and the
accuracy of any further adjustments may be reduced using the available data.