Calibration - Extech Instruments 445580 User Manual

CALIBRATION

The following verification and calibration procedures require the 33% and 75% RH
reference bottles which are supplied with the model 445582 kit.
Accuracy Verification
Checking the 33% or 75% RH Calibration
1. Insert meter's sensor into the 33% or 75% salt reference bottle
2. Place the meter and bottle inside the meter case
3. Check the reading after 40 minutes
4. Verify that the reading is within the accuracy specification.
Relative Humidity Calibration (33% and 75%)
Note: For best results, store the meter and salts in the closed case during the 40-minute
stabilization process.
33% Calibration
1. Make sure the meter is OFF.
2. Insert the meter sensor into the 33% salt reference bottle. Allow the meter to
stabilize for 40 minutes.*
3. While holding down the recessed CAL button (use a paper clip) press and release
the ON/OFF button.
4. Continue to hold the CAL button and the unit will power up and the display will flash
once.
5. When only the 'F' and 'C' icons appear on the display, release the CAL button. 'C' or
'F' (whichever was previously selected) will remain on the display.
6. Press and hold RESET for 3 seconds '%MIN' will appear when the key is released.
7. Momentarily press CAL. 'S' then '%MAX' will display.
8. Turn power off. The 33% calibration is complete. Leave the meter OFF and proceed
to the 75% Calibration below.
75% Calibration
1. Make sure the meter is OFF.
2. Insert the meter sensor into the 75% salt reference bottle. Allow the meter to
stabilize for 40 minutes.*
3. While holding down the recessed CAL button (use a paper clip), press and release
the ON/OFF button.
4. Continue to hold the CAL button and the unit will power up and the display will flash
once.
5. When only the 'F' and 'C' icons appear on the display, release the CAL button. 'C' or
'F' (whichever was programmed earlier) will remain on the display.
6. Press and hold RESET for 3 seconds. '%MIN' will appear in the display after the key
is released.
7. Press and hold RESET again for 3 seconds. '% MAX' will appear in the display after
the key is released
8. Ensure that '%MAX' is displayed then press CAL. 'S' will appear briefly and the
meter will return to normal operation.
9. Turn power off. The 75% calibration is now complete.
Note: If the salt at the bottom of the calibration bottles appears dry, the bottles
should be replaced.
* For testing purposes, the 40-minute stabilization period can be shortened.
However, for the most accurate calibration use the 40-minute period.
3 Models 445580 & 445582 Version 3.2 August 2003