Campbell Scientific CNR4 Net Radiometer - Manual (Page 56)

Appendix B. CNF4 Heater/Ventilator
'CNR4 multipliers
Public cnr4_mult(4)
Const pyranometer_up_mult = 1000/pyranometer_up_sensitivity
'(W/m^2/mV)
Const pyranometer_dn_mult = 1000/pyranometer_dn_sensitivity '(W/m^2/mV)
Const pyrgeometer_up_mult = 1000/pyrgeometer_up_sensitivity '(W/m^2/mV)
Const pyrgeometer_dn_mult = 1000/pyrgeometer_dn_sensitivity '(W/m^2/mV)
DataTable (cnr4_data,True,-1)
DataInterval (0,60,Min,10)
CardOut (1,-1)
Minimum (1,batt_volt,FP2,0,False)
Sample (1,logger_temp,FP2)
Average (4,cnr4(1),IEEE4,False)
Average (1,cnr4_T_C,IEEE4,False)
A
nr4_ verage (1,c T_K,IEEE4,False)
A ong_ verage (1,l up_corr,IEEE4,False)
Average (1,long_dn_corr,IEEE4,False)
Average (1,Rs_net,IEEE4,False)
Average (1,Rl_net,IEEE4,False)
Average (1,albedo,IEEE4,False)
Average (1,Rn,IEEE4,False)
EndTable
DataTable (cnr4_ts,True,-1)
DataInterval (0,1,Sec,10)
CardOut (1,-1)
Sample (4,cnr4(1),IEEE4)
Sample (1,cnr4_T_K,IEEE4)
EndTable
BeginProg
'Load the multiplier values for the CNR4
cnr4_mult(1) = pyranometer_up_mult
cnr4_mult(2) = pyranometer_dn_mult
cnr4_mult(3) = pyrgeometer_up_mult
cnr4_mult(4) = pyrgeometer_dn_mult
Scan (1,Sec,3,0)
PanelTemp (logger_temp,250)
Battery (batt_volt)
'CNR4 radiation measurements
VoltDiff (cnr4(),4,mV20C,1,True ,0,_60Hz,cnr4_mult(),0)
'CNR4 thermistor measurement
BrHalf (Vs_Vx,1,mv5000,16,Vx1,1,2500,True ,0,250,1.0,0)
Rs = 1000*(Vs_Vx/(1-Vs_Vx))
cnr4_T_C = 1/(1.0295e-3+2.391e-4*LN(Rs)+1.568e-7*(LN(Rs))^3)-273.15
'Convert CNR4 temperature to Kelvin
cnr4_T_K = cnr4_T_C+273.15
'Correct the long-wave radiation values from pyrgeometers
long_up_corr = long_up+5.67e-8*cnr4_T_K^4
long_dn_corr = long_dn+5.67e-8*cnr4_T_K^4
'Compute short-wave net radiation
Rs_net = short_up - short_dn
'Compute long-wave net radiation
Rl_net = long_up - long_dn
'Compute albedo
albedo = short_dn/short_up
B-10