Vaisala HMP155 - Manual (Page 63)

Chapter 6 ___________________________________________________Calibration and Adjustment
VAISALA _______________________________________________________________________ 61
One-Point Humidity and Temperature
Adjustment
To make a one-point humidity or temperature adjustment:
1. Carry out the chemical purge (if available). See section Chemical
Purge (Optional) on page 45.
2. Uncover the adjustment buttons on the probe by removing the
protective cover and removing the calibration seal.
3. Open the protective plug and you can see three buttons marked -, □
and +. There is also a two-colored indicator LED. See Figure 13 on
page 58.
4. Remove the filter and insert the probe into a measurement hole of
the salt chamber to do the humidity adjustment.
5. Press the ADJ button and hold it down until the green indicator
LED lights up. This puts HMP155 in RH calibration mode.
NOTE Do not touch the adjustment buttons before the conditions have
stabilized.
6. Using the - and + buttons, make sure the A
out
voltage is correct and
press the ADJ button. Green indicator LED turns off and back on.
7. To move on to the temperature adjustment, press the ADJ button
once and the red indicator LED lights up.
8. Insert the probe into the reference temperature.
NOTE Do not touch the adjustment buttons before the conditions have
stabilized.
9. Using the - and + buttons, make the temperature offset adjustment
by making sure the A
out
voltage is correct and press the
ADJ button. Red indicator LED turns off and back on.
10. Press the ADJ button one more time so that the red LED turns off
to indicate the probe has quit the calibration mode.