E-M-HP22-V1_21
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
HygroPalm HP22 hand-held indicator:
User Guide
Instruction Manual
Document Type
Page
12
of 16
Document title
© 2009-2010; Rotronic AG E-M-HP22-V1_21
5.4 Periodic calibration check of the probe
Both the Pt 100 RTD temperature sensor used in the probe and associated electronics are very stable
and should not require any calibration after the initial factory adjustment. Long term stability of the
ROTRONIC Hygromer humidity sensor is typically better than 1 %RH per year. For maximum accuracy,
calibration of the probe should be verified every 6 to 12 months. Applications where the probe is
exposed to significant pollution may require more frequent verifications.
a) Procedure for adjusting the probe from the HP22 keypad
Temperature adjustment
The keypad of the HP22 allows only a 1-point adjustment of temperature. The effect of a 1-point
temperature adjustment is to add the same offset to all measured values.
When temperature is stable, press the MENU key to show the internal menu on the display
Use the (-) key to select Temperature Adjust and press the ENTER key
Make sure that the text line beginning with RefValue is highlighted and press the ENTER key
Use the (+) or (-) key to change the reference value to match the temperature reference
Use the (-) key to highlight the Adjust text line and press the ENTER key
The HP22
confirms the adjustment with the message “Adjust OK”
Press the MENU key twice to exit the menu and return the HP22 to normal operation
Notes:
o
Any temperature adjustment should be done prior to adjusting humidity
o
The calibration point is automatically deleted from the probe memory after an adjustment
o
Because the HP22 has no real time clock, the date of the adjustment is not written to the probe. If
retaining the adjustment date is important, use the HW4 software to adjust the probe.
Humidity adjustment
The keypad of the HP22 allows a multi-point adjustment of humidity. The effect of a humidity adjustment
depends on the number of calibration points present in the probe memory prior to the adjustment:
-
one calibration point: offset added to all measured values
-
two calibration points: offset and slope
-
three or more calibration points: offset, slope, linearity
For maximum accuracy use at least 3 to 4 calibration points distributed equally across the measurement
range of interest. The calibration points (maximum 100) can be acquired in any order but we recommend
going from low humidity values to high humidity values.
When humidity is stable, press the MENU key to show the internal menu on the display
Use the (-) key to select Humidity Adjust and press the ENTER key
Make sure that the text line beginning with RefValue is highlighted and press the ENTER key
Use the (+) or (-) key to change the reference value to match the reference humidity
Use the (-) key to highlight the Acquire text line and press the ENTER key
Note that the “Acquired” counter is incremented by 1 (number of calibration points in the probe
memory)
When all calibration points have been acquired, use the (-) key to highlight the Adjust text line and
press the ENTER key.
Do not adjust the probe before having acquired all calibration points
.
The HP22
confirms the adjustment with the message “Adjust OK”
Press the MENU key twice to exit the menu and return the HP22 to normal operation
