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The probes are calibrated in our laboratory at 23°C at the points of 75%RH, 33%RH and 11.4%RH.
On request, the probes can be checked at different isotherms.
The calibration of the temperature sensor by the user is not required: the sensor is calibrated
in the factory and the Callendar Van Dusen parameters are recorded in the SICRAM module.
In order to calibrate the instrument correctly, it is very important for the probe and the saturated
solutions to maintain the same temperature and that this is as stable as possible during the entire
calibration operation.
Calibration sequence:
1.
Unscrew the sensor protection on the top of the probe.
2.
In its place screw the bored cap with the threaded ring very well at the base (there are two
types of thread: M24x1,5 and M12x1, so use the appropriate one).
3.
Open the cap for the 75%RH saturated solution.
4.
Should there be any drops of solution inside the measuring chamber, dry them with some
blotting paper.
5.
Insert the probe in the container, making sure the cap at the base is screwed well.
The
measuring chamber must be closed perfectly, otherwise it will not get saturated
: it is
essential that no air passes through it.
6.
Wait at least 30 minutes
.
7.
Press contemporarily
FUNC/Enter
and
UNIT/UserCAL
: the message "PROB_CAL_EXIT
_ OR_75_OR_33_OR_11" is scrolled in the upper part of the display. To proceed with the
calibration, using the arrows select 75%, and confirm using UNIT/UserCAL. [To exit
without calibrating the probe, press UNIT/UserCAL when the message "nonE" (None)
appears].
8.
The relative humidity read by the probe is shown: if necessary, correct the value of the
saturated solution against the 75.0% proposed by the instrument using the arrows
and
.
The temperature is measured by the Pt100 or TC sensor. Press
ENTER
to confirm the
calibration point. The instrument returns to the calibration main page and displays "nonE".
To proceed with another point, select it using the arrows and confirm it using
UNIT/UserCAL [to return to measurement mode, press UNIT/UserCAL when the message
"nonE" appears].
9.
Remove the probe from the 75%RH container and close it immediately using its cap.
Calibrating the points at 33%RH and 11%RH
Repeat the points from 3) to 9) using the saturated salts at 33%RH and 11%RH
When completed, unscrew the ring with the cap, and screw the protection grid back on the sensors.
The calibration is now complete.
Important notes:
1)
Do not let hands touch the RH sensor
2)
The sensor base is in alumina so it could easily break
3)
During the entire calibration cycle keep the temperature as constant as possible; plastic
materials are poor thermal conductors, therefore some time is needed for them to reach a
thermal equilibrium
4)
In case no satisfactory results are obtained, check that:
•
the sensor is not faulty, corroded or dirty
•
the measuring chamber is perfectly closed during calibration
•
the saturated solutions are not exhausted A saturated solution at 11%RH or 33%RH is
exhausted when there is no more salt inside between the two walls but only a thick liquid: in
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