HD35
- 59 -
V1.12
8.6.5
C
ALIBRATING THE RELATIVE HUMIDITY SENSOR
The sensor can be calibrated in the two points 75%RH and 33%RH. Before starting the calibra-
tion procedure, it’s better to check if a new calibration is necessary, with the aid of 75.4%RH
and 33%RH saturated solutions (except HD35ED[G]1…B models, that require a climatic cham-
ber): a calibration will be performed only if an error of a few humidity points in one of the two
calibration points is detected.
The sensor can be calibrated in both points or in one point only.
Preliminary operations before calibration:
Check that the chamber with the saturated saline solutions contains at the same time:
• solid state salt,
• liquid solution or wet salt, in particular for the 75%RH solution.
The instrument and the saturated solutions to be used for this operation must be placed in a
stable temperature environment for the whole calibration period. Wait for at least a couple of
hours with a stable temperature so that the instrument and the saturated solutions reach a
thermal balance with the environment before starting the calibration procedure. In order to ob-
tain a good calibration, it is crucial that the probe and the solution have the same temperature.
Bear in mind that plastic material is a bad heat conductor.
Calibration should be performed at a temperature ranging within 15 and 30°C.
Calibration procedure:
1.
Unscrew the probe protection grid and screw the M12×1 threaded ring.
Avoid any contact of the sensitive element with your hands or other objects or liquids. If
some liquid has formed inside the measuring chamber, dry it with a clean absor-
bent paper towel.
2.
Unscrew the cap of the saturated solution. Screw the threaded ring with the probe on the
saturated solution container and wait for at least 30 minutes.
3.
Access the menu with the administrator password and select the item CAL_MENU (custom
LCD) or Calibration (graphic LCD). Press ENTER to confirm.
4.
Select the item RH_75%_CAL (custom LCD) or RH 75% calibration (graphic LCD) to calibrate
the point 75%RH; select the item RH_33%_CAL (custom LCD) or RH 33% calibration (graphic
LCD) to calibrate the point 33%RH. Press ENTER to confirm.
5.
In the models with custom LCD, the blinking value of the saturated solution at the tem-
perature measured by the probe is displayed. In the models with graphic LCD, the value
measured by the instrument (on the left) and the calibration point (on the right) appear.
RH 75% CALIBRATION
S E T
Set sensor in RH 75%
75.2
concentration
Meas. [%] Cal. [%]
71.2 75.2
OK
.
CANCEL
select <ENTER>confirm
24.5
°C
Graphic LCD
Custom LCD
Note: the suggested calibration value is not updated if the measured temperature changes
after starting calibration. If necessary, set manually the calibration value to the value of the
saturated solution at the measured temperature using
/
keys (see table 8.6.1 below).
6.
In the models with custom LCD, press ENTER to confirm the value; in the models with
graphic LCD, select the option OK and confirm with ENTER. The instrument stores the
calibration and returns to the calibration submenu.
Summary of Contents for HD35AP series
Page 120: ...HD35 120 V1 12 HD35EDLM TC...
Page 141: ...NOTES...
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