Campbell Scientific HMP45C Temperature and RH Probe - Manual (Page 18)

Model HMP45C Temperature and Relative Humidity Probe
SatVP(e_Sat, AirTC)
'Compute Vapor Pressure, RH must be a fraction
e_kPa = e_Sat * RH_Frac
CallTable(Temp_RH)
NextScan
EndProg
CR10(X) Program that Computes Vapor Pressure and Saturation Vapor Pressure
;Turn the HMP45C on.
;
01: Do (P86)
1: 41
Set Port 1 High ;Jumper wire from SW12V control to C1
;Orange wire (C1) if older wiring
;Green wire (C1) if using SW12V device
;For CR23X or CR5000 use 49 for SW12V internal
;control port
;Pause 150 mSec before making measurements so the
;probe can stabilize on true readings.
;
02: Excitation with Delay (P22)
1: 1
Ex Channel
2: 0 Delay W/Ex (units = 0.01 sec)
3: 15 Delay After Ex (units = 0.01 sec)
4: 0 mV Excitation
;Measure the HMP45C temperature.
;
03: Volt (SE) (P1)
1: 1
Reps
2: 5 2500 mV Slow Range ;CR510, CR500 (2500mv); CR23X (1000 mV);
21X, CR7 (5000 mV)
3: 3 SE Channel ;Yellow wire (SE 3), white or purple wire (AG)
4: 1 Loc [ T_C ]
5: .1 Mult
6: -40 Offset
;Measure the HMP45C relative humidity.
;
04: Volt (SE) (P1)
1: 1
Reps
2: 5 2500 mV Slow Range ;CR510, CR500 (2500mv); CR23X (1000 mV);
21X, CR7 (5000 mV)
3: 4 SE Channel ;Blue wire (SE 4), white or purple wire (AG)
4: 2 Loc [ RH_frac ]
5: .001 Mult
6: 0 Offset
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