5
EDDYSENSOR Operating Manual
F1 and F2 filters
The frequencies given for the high pass and low pass filters in the filter
tables in the appendix correspond to the speed ranges shown on the right.
The switch settings required can be coarsely set by using the graphs shown
on the following pages to match the line speed range where HPH/HPL is the
lower limit and LPH/LPL the upper limit. The precise settings required can
be found in the tables included in the appendix.
Ideally, the filter settings should be established using a test piece prepared
with standard defects and a test bench. The settings should be made so
that any interference signals are suppressed while the defect signal itself
remains undistorted. For optimum results the band pass should be as wide
as possible but as narrow as necessary.
To give a reasonable bandwidth we recommend:
V
Line
/ 4:
Switch setting HPH/HPL
V
Line
x 2:
Switch setting LPH/LPL
Filter-to-speed relationship for
filters F1 and F2
PCB
Front panel
Side view of the printed
circuit board (PCB)
LPH
HPH
HPL
Low pass filter
e.g.for a setting of 17,
LPH=1 LPL=7
High pass filter
e.g.for a setting of 20,
HPH=2 HPL=0
LPL
For both of these filters there are two pairs of switches, one pair for the low
pass filter (LPH/LPL) and one pair for the high pass filter (HPH/HPL) shown
in the diagram below. The two settings together form the required band
pass filter. The settings are given in the graphs following and in the table
included at the end of the document.
