Calibrating and adjusting the temperature and humidity control
11 Calibrating and adjusting the temperature and humidity
control
The temperature and humidity control of the unit have to be calibrated and if necessary ad-
justed annually and after the following repair works:
Replacing the inner chamber Pt100 temperature sensor (-
3B1
) (chap. 7.9)
Replacing the humidity sensor incl. board (-
3B2
) (chap. 7.10)
Replacing the controller MB1 I/O board (-
3N2
) (chap.8.8.1)
Replacing the controller display (-
3N1
) (chap. 8.9)
At the calibration the temperature and humidity values measured and displayed by the KBF are compared
with values measured and displayed by external reference measuring instruments.
If the deviations of the temperature or humidity values of the KBF and the reference measuring instruments
exceed defined values, called confidence criteria, the temperature or the humidity control of the KBF have to
be adjusted.
The reference measuring instruments for temperature and humidity must have a valid calibration certificate
which has been approved by a recognized standards or calibration authority or regulatory body.
The measuring uncertainty of the reference measuring instrument for the temperature should be below
+/-0.5 K.
The measuring uncertainty of the reference measuring instrument for the humidity should be below
+/-2.0 % r.H..
11.1 General execution of the calibration
1.
The reference measuring instruments should have sensors connected to the display of the instrument
via a slim cable that can be placed through the silicone access port without causing a leak.
2.
Place the usual number of racks in the inner chamber of the KBF.
3.
Attach the sensors of the reference measuring instruments in the middle of the rack which is posi-
tioned in the center of the KBF useable volume.
4.
Conduct the sensor cables out through the silicone access port in such a way that you can tightly
close the access port with its plug.
5.
Close the glass door and the outer door.
6.
Switch on the unit and set the operating parameters set-points (temperature, humidity, fan speed) to
that values at which the unit shall be calibrated (chap. 11.2).
Steady-state condition
The steady-state condition is that operating state at which the values of temperature and humidity are not
changing by more than the specified fluctuations in the useable space (see chap. “Technical data” in the op-
erating manual).
If the KBF has been stored at the permitted ambient operating temperature of +18°C to +32°C /
64.4°F
to
89.6°F
for more than 12 hours, the empirical time to reach the steady-state condition for the KBF is 1-2 hours
after switching on.
Before starting the calibration and adjustment the unit must be in steady-state condition.
120
Service Manual KBF (E5.2) 04-2015
