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in_hypalm_aw1_v3.doc
ADJUST M.PT (full probe calibration against a reference)
Definition
The Adjust M.PT function permits the full calibration of the ROTRONIC HygroClip digital probe
against a known reference environment. This function is designed to permit calibration at 2
temperature values and at up to 4 relative humidity values.
Note:
Water activity calibration is actually a calibration of the relative humidity signal provided by the
probe. The parameter used is relative humidity which is equal to 100 x aw.
For example, 1.00 aw = 100 %RH.
Selections
The Adjust M.PT function offers the following choices (use the UP and DOWN keys):
RHS
:
Humidity calibration using the ROTRONIC Humidity Standards
1)
Humidity
:
Humidity calibration using any suitable reference environment
Temperature
:
Temperature calibration using any suitable reference environment
1) For humidity calibration, ROTRONIC offers convenient, certified humidity standards to
generate known humidity values (for more details, see Appendix 3 - Humidity Calibration).
Procedure
Please be sure to observe the following rules:
a) Always calibrate temperature first (if temperature needs to be calibrated)
b) When calibrating temperature (2 points), always calibrate at the low value first. The
instrument is programmed to use the low temperature value to compute the offset and
the high temperature value to compute the gain.
T-low < 70
q
C (158
q
F) : used to compute the calibration offset
T-high
70
q
C (158
q
F) : used to compute the calibration gain
For best accuracy, we recommend using a T-low value close to 20
q
C (68
q
F). Preferably,
the difference between T-high and T-low should be at least 50
q
C (90
q
F)
When calibrating humidity (2, 3 or 4 points) with the ROTRONIC humidity standards, always
follow the sequence 35 %RH, 80 %RH, 10 %RH or 5 %RH, 0 %RH. When using a reference
other than the ROTRONIC humidity standards, use reference conditions that are within the
following brackets and observe the sequence:
>25 %RH…
55 %RH
1)
: used to compute the calibration offset
>55 %RH
1)
: used to compute the calibration gain
>1 %RH…
25 %RH
: sensor linearity adjustment
1 %RH
: sensor linearity adjustment
The HygroPalm AW1 is programmed to automatically recognize these brackets.
1) For best accuracy, we recommend using values close to 35 %RH and 80 %RH
