Vaisala HMT120 User Manual

Also see for HUMICAP HMT120 Series: Quick guide Quick guide

Contents

Vaisala HMT120 User Manual Manual pdf 61 page image

When making a 2-point adjustment, the difference between the two referenceconditions must be at least 50 %RH. If the difference is < 50 %RH, the adjustmentcannot be made.1. Remove the filter from the transmitter's probe and insert the probe head into the lowerreference condition.2. Press ADJUST to continue adjusting.3. Choose 2-point adjustment from the MI70 adjustment menu and press SELECT.4. Press READY when the reading has stabilized in the first reference condition (can take 30minutes or more). You can follow the stabilization from the GRAPH display.5. Enter the correct reference value of the first condition with the arrow buttons and pressOK.6. Remove the probe from the first reference condition and insert the probe head into thehigher humidity reference condition.7. Press READY when the reading has stabilized in the second reference condition (can take30 minutes or more). You can follow the stabilization from the GRAPH display.8. Enter the correct reference value of the second condition with the arrow buttons andpress OK.9. Confirm the adjustment by pressing YES (by pressing NO you return to adjustment modedisplay and no changes are made). If the difference between the two reference conditionsis less than 50 %RH, adjustment cannot be done.10. The adjustment is done. Press BACK and EXIT to return to the basic display.11. Turn off the MI70 and detach the connection cable.6.3.4 LiCl-NaCl AdjustmentComplete the steps listed in Adjusting RH and T with MI70 Hand-Held Indicator(page 56) before continuing with this adjustment option.This adjustment is made using relative humidity references 11.3 % RH (LiCl) and75.5 % RH (NaCl).1. Remove the filter from the transmitter's probe and insert the probe head into the LiCl saltchamber.2. Press ADJUST to continue adjusting.3. Choose LiCl-NaCl autom. from the MI70 adjustment menu and press SELECT. Press OK toaccept the note telling about references.Chapter 6 – Calibration and Adjustment59