Vaisala hmt120 - Page 4

5. Maintenance....................................................................................................48
5.1 Removing and Fastening Fixed Humidity Probe........................................48
5.2 Removing and Fastening Remote Humidity Probe................................... 49
5.3 Testing Analog Outputs................................................................................ 50
5.4 Replacing the HUMICAPâ Sensor.................................................................51
6. Calibration and Adjustment..................................................................... 52
6.1 Calibration and Adjustment Overview ........................................................52
6.2 Push-Button Calibration................................................................................ 53
6.2.1 Adjusting Humidity and Temperature with Push Buttons..................53
6.3 Adjusting RH and T with MI70 Hand-Held Indicator..................................56
6.3.1 Field Checking and Adjustment Using a Calibrated
Reference Probe...................................................................................... 57
6.3.2 1-Point Adjustment Using a Calibrator................................................. 58
6.3.3 2-Point Adjustment Using a Calibrator.................................................58
6.3.4 LiCl-NaCl Adjustment.............................................................................59
6.3.5 Temperature Field Check and Adjustment Using a
Calibrated Reference Probe.................................................................. 60
6.4 Adjustment with HMI41................................................................................. 60
6.4.1 Connections and Selecting the Calibrator Function...........................62
6.4.2 Adjusting Oset and Gain with HMI41..................................................63
6.4.3 Troubleshooting HMI41 Adjustment......................................................67
7. Troubleshooting............................................................................................69
7.1 Error Codes..................................................................................................... 69
7.2 Solving Typical Problems.............................................................................. 70
7.3 Analog Output Error Notification..................................................................71
8. Technical Data................................................................................................ 72
8.1
Specifications..................................................................................................72
8.2 Spare Parts and Accessories......................................................................... 74
8.3 Transmitter Dimensions................................................................................. 75
Appendix A:
Calculation Formulas................................................................... 77
A.1 Calculation Formulas Overview.................................................................... 77
A.2 Dewpoint Temperature.................................................................................. 77
A.3 Dew/frostpoint Temperature Calculation.................................................... 78
A.4 Mixing Ratio Calculation................................................................................ 78
A.5 Saturation Vapor Pressure Calculation........................................................ 79
A.6 Water Vapor Pressure Calculation................................................................79
A.7 Absolute Humidity Calculation.....................................................................80
A.8 Enthalpy Calculation......................................................................................80
A.9 Accuracies of Calculated Variables..............................................................80
A.9.1 Accuracy of Dewpoint Temperature °C................................................80
A.9.2 Accuracy of Mixing Ratio g/kg (Ambient Pressure 1013 mbar)..........81
A.9.3 Accuracy of Wet Bulb Temperature °C..................................................81
A.9.4 Accuracy of Absolute Humidity g/m
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...................................................82
HMT120 User Guide M211244EN-C
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