Vaisala hmt120 Quick Manual

Also see for HUMICAP HMT120 Series: User guide Quick guide

Vaisala hmt120 Quick Manual Manual pdf 11 page image

__________________________________________________________________________ EnglishVAISALA _______________________________________________________________________ 11Humidity and Temperature AdjustmentTo make a humidity or temperature adjustment (the same instructionsapply to both one-point and two-point calibration):1. Open the transmitter cover and you can see three buttonsmarked ADJ, + and -.2. Press the ADJ button and hold it down until the green indicatorLED begins to blink slowly (800ms cycle time).3. HMT120 transmitter is now in RH calibration state. Analog outputand optional display will still follow the actual measured RH value.If you do not wish to perform the RH adjustment at this time, pressADJ button one more time.4. Remove the filter and insert the probe into a measurement hole ofthe dry end reference chamber (for example, LiCl: 11 % RH) to dothe low humidity offset adjustment.NOTE Do not touch the adjustment buttons before the conditions havestabilized. This takes approximately 30 minutes.5. Press either the - or + button at least once, make sure that the I outcurrent is correct, adjust using the - and + buttons if needed, andpress the ADJ button again. The green indicator LED begins toblink faster (400ms cycle time).If you do not wish to perform the two-point RH adjustment at thistime, press the ADJ button one more time. Skip step 6.If one-point calibration is done at more than 50% RH, a gainadjustment is done instead of an offset adjustment.6. Insert the probe into the high end reference chamber (for example,NaCl: 75 % RH chamber in the humidity calibrator HMK15) anddo the high humidity gain adjustment by using the - and + buttonsto make sure the I out current is correct (you have to press either - or+ at least once even if the value is correct). To finish the RHcalibration, press the ADJ button. The green LED is now turned offand the red indicator LED begins to blink slowly (800ms cycletime).7. HMT120 transmitter is now in T calibration state. Analog outputand optional display will still follow the actual measured T value.If you do not wish to perform the T adjustment at this time, pressADJ button one more time to finish the calibration, then skip therest of the steps.8. Insert the probe into a known reference temperature (if HMK15Humidity Calibrator is not used) and let the temperature readingstabilize.