Campbell Scientific HMP60 Temperature and Relative Humidity Probe - Manual (Page 22)

HMP60 Temperature and Relative Humidity Probe
7.6.2 Sample CR10(X) Program that Computes Vapor Pressure
and Saturation Vapor Pressure
;Measure the HMP60 temperature.
;
01: Volt (SE) (P1)
1: 1
Reps
2: 5 2500 mV Slow Range ;CR510 (2500 mV); CR23X (1000 mV); 21X,
CR7 (5000 mV)
3: 3 SE Channel ;Black wire (SE 3), Blue wire (G)
4: 1 Loc [ T_C ]
5: .1 Mult ;See Table 7-2 for alternate multipliers
6: -40 Offset ;See Table 7-2 for alternate offsets
;Measure the HMP60 relative humidity.
;
02: Volt (SE) (P1)
1: 1
Reps
2: 5 2500 mV Slow Range ;CR510 (2500 mV); CR23X (1000 mV); 21X,
CR7 (5000 mV)
3: 4 SE Channel ;White wire (SE 4), Blue wire (G)
4: 2 Loc [ RH_frac ]
5: .001 Mult ;See Table 7-3 for alternate multipliers
6: 0 Offset
;Limit the maximum value of relative humidity
;to 1 (expressed as a fraction).
;
03: If (X<=>F) (P89)
1: 2
X Loc [ RH_frac ]
2: 3 >=
3: 1 F
4: 30 Then Do
04: Z=F (P30)
1: 1
F
2: 0 Exponent of 10
3: 2 Z Loc [ RH_frac ]
05: End (P95)
;Compute the saturation vapor pressure in kPa.
;The temperature must be in degrees Celsius.
;
06: Saturation Vapor Pressure (P56)
1: 1
Temperature Loc [ T_C ]
2: 3 Loc [ e_sat ]
;Compute the vapor pressure in kPa.
;Relative humidity must be a fraction.
;
07: Z=X*Y (P36)
1: 3
X Loc [ e_sat ]
2: 2 Y Loc [ RH_frac ]
3: 4 Z Loc [ e ]
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