be reached by using several foils - 50um each. The mean coating
thickness should be calculated from 5 ... 10 readings. The statistics
program is very useful here.
NOTE
: For coatings thicker than 300 um, the influence of roughness
generally is of no importance and it will not be necessary to apply above
calibration methods.
4-3.General Remarks on Measurement
-After careful calibration has been made, all subsequent measurements
will lie within the guaranteed measuring tolerance.
-Strong magnetic fields near generators or live rails with strong currents
can affect the reading.
-When using the statistics program for obtaining a mean value it is
advisable to place the probe several times at a typical measuring spot.
Any false readings or outliers can be removed immediately via MENU
system.
-The final reading derives from the statistical calculation and from the
guaranteed tolerance levels of the gauge.
-Coating Thickness D =X±s±
µ.
Example:
Readings: 150 µm, 156 µm, 153 µm
Mean value: X=153 µm
Standard deviation: s=±3 µm
Measuring uncertainty: µ=±(1% of r 1 µm)
D
=153±3±(1,53 µm +1 µm)
=153±5,5 µm
5. Limit Function
-Limits can be entered in DIRECT and a selected GROUP memory at
any time, i.e. before, during and after a series of measurements.
There is practical use for limits.
-Any reading which falls outside the set tolerance limits will be registered
by a warning indication:
H: reading above HI limit.
L: reading below W limit.
Please set the limit values using MENU system.
