Appendix C. Absolute Humidity
C-2
'Clear: Shield - Ground Symbol
Public
AirTC :
Units
AirTC = °C
Public
RH :
Units
RH = %
Public
e_Sat :
Units
e_Sat = kPa
Public
e_kPa :
Units
e_kPa = kPa
DataTable
(Temp_RH,True,-1)
DataInterval
(0,60,Min,0)
Average
(1,AirTC,FP2,0)
Sample
(1,RH,FP2)
Sample
(1,e_kPa,IEEE4)
EndTable
BeginProg
Scan
(5,Sec,1,0)
PortSet
(9,1)
'Turn on switched 12V
Delay
(0,2,Sec)
'2-second delay
'EE181 Temperature & Relative Humidity Sensor measurements
'AirTC and RH:
VoltSe
(AirTC,1,mV2500,1,0,0,_60Hz,0.1,-40.0)
VoltSe
(RH,1,mV2500,2,0,0,_60Hz,0.1,0)
PortSet
(9,0)
'Turn off switched 12V
'Calculate Saturation Vapor Pressure
SatVP
(e_Sat, AirTC)
'Compute Vapor Pressure, RH must be a fraction
e_kPa = e_Sat * RH/100
CallTable
(Temp_RH)
NextScan
EndProg
CRBasic Example C-2. CR6 Program that Computes Vapor Pressure and Saturation Vapor
Pressure
'Program measures EE181 with single-ended inputs once every 5 seconds
'and stores the average temperature and a sample of the relative
'humidity every 60 minutes.
'Wiring Diagram
'==============
'EE181
'Wire CR6
'Color: Function - Terminal
'------ -------- --------
'Red: Power - SW12-1
'Yellow: Temperature signal - U1
'Blue: Relative Humidity signal - U2
'Black: Power Ground - Ground Symbol
'Clear: Shield - Ground Symbol
Public
AirTC :
Units
AirTC = °C
Public
RH :
Units
RH = %
Public
e_Sat :
Units
e_Sat = kPa
Public
e_kPa :
Units
e_kPa = kPa
DataTable
(Temp_RH,True,-1)
DataInterval
(0,60,Min,0)
Average
(1,AirTC,FP2,0)
Sample
(1,RH,FP2)
Sample
(1,e_kPa,IEEE4)
EndTable
BeginProg
Scan
(5,Sec,1,0)
SW12
(1,1 )
'Turn on switched 12V
Delay
(0,2,Sec)
'2-second delay
Summary of Contents for EE181
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