Memmert HCP 246 Humidity Chambers (Generation 2003) - Manual (Page 36)

HCP page 36
17.2 Humidity
User-calibration of the unit at the controller, using two humidity points:
RH 20
Humidity calibration at 20% relative humidity
RH 90
Humidity calibration at 90% relative humidity
Either a positive or a negative calibration correction can be applied to each selected calibration point.
General calibration instructions:
1. Select the required calibration humidity in SETUP and set the corresponding calibration
correction to 0.0 °C.
2.
Measure the deviation from the selected calibration humidity under steady conditions, using a
reference instrument.
3. Set the calibration correction in SETUP. If the measured reference humidity is too low, the
calibration correction setting has to have a negative sign.
4. Carry out a check measurement using the reference instrument.
5. The procedure can be carried out for up to 2 calibration humidities.
Example: Humidity deviation at the load at 90% has to be corrected:
1. Set calibration humidity in SETUP on RH 90 and set the corresponding calibration correction
to 0.0 %
2.
Using a calibrated reference instrument, an actual humidity of 88% is measured in normal
operation for a humidity setting of 90 %.
3.
In SETUP set calibration correction for RH 90 to -2.0 %
4. The reference instrument should read 90.0% after the unit has settled down.
5. An additional calibration can be programmed with RH 20 at 20% relative humidity.
rh 20
+3
%
rh 90
-2 %
factory
calibration
60% 40% 0% 20% 80% 100%