Campbell Scientific HMP45C Temperature and RH Probe User Manual
Page 15

Model HMP45C Temperature and Relative Humidity Probe
BeginProg
Scan(1,Sec,1,0)
'HMP45C Temperature & Relative Humidity Sensor measurements AirTC and RH:
SW12
(1
)
Delay(0,150,mSec)
VoltDiff
(AirTC,1,mV2500,2,True,0,_60Hz,0.1,-40)
VoltDiff
(RH,1,mV2500,1,True,0,_60Hz,0.1,0)
SW12
(0)
If RH>100 And RH<108 Then RH=100
CallTable(Temp_RH)
NextScan
EndProg
CR10(X) Program using Differential Measurement Instructions Using SW12V on Datalogger
;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 (Diff) (P2)
1: 1
Reps
2: 5
2500 mV Slow Range
;CR510, CR500 (2500mv); CR23X (1000 mV);
21X, CR7 (5000 mV)
3: 2
DIFF
Channel
;Yellow wire (2H), jumper (2L to 1L)
4: 1
Loc [ T_C ]
5: .1
Mult
;See Table 5-1 for alternative multipliers
6: -40
Offset
;See Table 5-1 for alternative offsets
11