Appendix A. Example Programs
A-6
'Compute Net short-wave radiation, Net long-wave radiation, Albedo and Net Radiation
NR01TC=NR01TK-273.15
NetRs=SR01Up-SR01Dn
NetRl=IR01Up-IR01Dn
Albedo=SR01Dn/SR01Up
UpTot=IR01Up
DnTot=IR01Dn
NetTot=UpTot-DnTot
IR01UpCo=5.67*10^-8*NR01TK^4
IR01DnCo=5.67*10^-8*NR01TK^4
'Call Data Tables and Store Data
CallTable(Table1)
NextScan
EndProg
Proper entries for the input channels will vary with program and
input channel usage.
A.3 CR3000 Program that Controls Heater
This program applies power to the NR01 heater using the SW12V relay
controller and the pulse width modulation instruction (PWM ()).
Rather than using 0 °C as a set point for the heater, the program below uses the
dewpoint value. The datalogger calculates dewpoint using the relative
humidity (RH) measurements provided by the HMP45C Temperature/Relative
Humidity probe. Enter 0 °C as the set point for the heater when a
temperature/RH probe is not used.
The algorithm turns the heater on/off at 4 Hz. The duty cycle of the pulse is
changed depending on how close the radiometer body temperature is to the
dewpoint temperature. At or below the dewpoint, the duty cycle is 100%. It
drops off linearly to 20% until the body temperature is 5 °C above the
dewpoint. For body temperatures greater than 5 °C above the dewpoint, the
duty cycle continue to drop linearly, but with a different slope, until 0% at
33 °C above the dewpoint. If necessary, the user can change the two duty-
cycle slope transitions.
'CR3000 Series Datalogger
'*** Wiring ***
'ANALOG INPUT
'5H HMP45C temperature signal (yellow)
'5L HMP45C signal reference (white)
'gnd HMP45C shield (clear)
'6H HMP45C relative humidity signal (blue)
'6L short jumper wire to 5L
'10H NR01 Pt100 signal (white)
'10L NR01 Pt100 signal reference (green)
'gnd NR 01 Pt100 shield (silver)
'11H NR01 downwelling shortwave radiation signal (red)
'11L NR01 downwelling shortwave radiation signal reference (blue)
'gnd NR01 shield (silver)
'12H NR01 upwelling shortwave radiation signal (white)
'12L NR01 upwelling shortwave radiation signal reference (green)
NOTE
