Point adjustment – Vaisala MM70 User Manual
Page 54
USER'S GUIDE____________________________________________________________________
have to feed the reference values, the MM70 displays the accurate
value based on the measured temperature and the Greenspan table
stored into the memory of the MM70. Make the adjustment as
instructed in the section below (select LiCl-NaCl autom. on item 8
and follow the display instructions).
2-point Adjustment
Low humidity references 0 % (Nitrogen)/ 11.3 % (LiCl) and higher
humidity references 75 % (NaCl)/ 97 % (K2SO4) are recommended
for two-point adjustment. Ensure that the difference between the
humidity references is more than 50 %.
1.
When adjusting both relative humidity and temperature, please
make the temperature adjustment first.
2.
Check that the MM70 is switched on.
3.
Take out the screw from the probe handle to expose the
calibration button. Press the button with a small screwdriver.
When pressing the button, indicator turns to adjusting mode.
4. Press
the
OK key to start the adjustment mode.
5. Select
RH, press the SELECT key.
6.
To check the environmental settings, press the YES key. To
continue directly to adjustment mode, press the NO key.
7.
Now the adjustment mode is on, press the ADJUST key to
select the adjustment method.
8. Select
2-point adjustment, press the SELECT key. Press the
OK key to continue.
9.
Set the probe to a lower reference relative humidity. If using
HMK15 calibrator, use the adapter fitting (13.5 mm hole).
10. You can follow the stabilization from the graph display, by
pressing the GRAPH key. When the reading is stabilized, press
the READY key.
11. Enter value for the lower reference humidity by using the arrow
keys. Press the OK key.
12. Set the probe to the higher reference humidity. You can follow
the stabilization from the graph display, by pressing the
GRAPH key. When the reading is stabilized, press the READY
key.
13. Enter value for the higher reference humidity by using the arrow
keys. Press the OK key.
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