Zero-Point Calibration; Single-Point Calibration - Trotec BB20 Manuel D'utilisation

back to the item "Calibration" . Press the blue button
again to return to main mode, in which the calibration
is performed .
The display now shows "cal" and "zero" . The follo-
wing messages are possible:
• c al n: no single or two-point calibration exists in
the appliance
• c al 1~2: a single or two-point calibration exists
• z ero n: no zero-point calibration exists
• z ero Y: a zero-point calibration exists
Preparatory measures before calibration:
A) Switch the measuring instrument on at least 10 cm
away from any metal
B) Basic sample and necessary films (calibrationstandard)
C) Set the working mode to single or continuous mode
in the MENU .

Zero-point calibration

(Calibration mode does not necessarily have to be
activated for this)
1. Briefly place the probe vertically against an uncoated
sample (zero layer thickness) .
2 . The combination <x .x um> appears on the display .
The mode of operation in continuous mode differs
from the mode of operation in single measuring
mode . Further details can be found in the section
on measuring modes . Remove the probe again and
keep it at least 10 cm away from the metallic substrate.
3. Press and hold the zero button for approx. 1.5 se-
conds; The combination <0.0 um> "Cal1", "ZeroY"
appears on the display . This means that a single-
point and a zero-point calibration have been carried
out . The calibration is finished .
4 . Repeat the procedure a few times . The calibration
system always stores the average value of the pre-
ceding calibration point .
you can delete the old zero-point calibration in the
menu before performing a new zero-point calibra-
tion . the measuring instrument always calculates
the average value of the last 5 calibrations . If the
memory is full, the old calibration value is replaced
by the new value . It is recommended to perform a
zero calibration before each measurement .
G
Operating manual – layer thickness measuring instrument BB 20

Single-point calibration

DThis method is recommended for highly precise mea-
surements on very thin coatings, small components
and hardened and low-alloy steel .
1. Activate the calibration mode as described above.
2 . First of all, perform a zero-point calibration .
3 . Place the calibration film on an uncoated sample,
place the probe against it and remove it again as
soon as the measurement has taken place . Press UP
(upward arrow) or DOWN (downward arrow) in order
to set the necessary film thickness . The film should
be approximately as thick as the estimated coating
thickness .
4 . Repeat step 3 a few times in order to minimise the
scattering of the calibration values by automatic deter-
mination of an averaged value .
5 . Now perform the measurement on the actual coating
by applying the probe to a coated sample section .
6 . Press the zero button to adopt the current calibration .
7 . To exit from the current calibration, press the blue
button . Otherwise, the calibration takes place auto-
matically after 30 seconds .
Sometimes calibrations have to be deleted, e .g . after
entering an incorrect calibration value . to do this,
proceed as follows:
Menu => Delete => Delete Group Data . After that,
"cal n" and "zero y" appear on the display .
this procedure deletes all data, limit values and
single and two-point calibrations . the zero-point
calibration is not affected by this . this reactivates
the error value for the basic calibration . the ba-
sic calibration is used for measurement on even
surfaces .
the measuring instrument calculates the average
value of the last 5 calibrations . When the memory
is full, the oldest calibration value is replaced by
the last new value .
The film calibration can be performed as often as ne-
cessary during an ongoing series of measurements .
The old calibration is overwritten; the zero calibration
remains in the memory .
B - 7