! VAISALA
! Upper Air Division                 1995-02-09
!
! This is an equation script file for ECC ozone sensor.
!
! If changes to this script are required, please note
! the following:
! 1) All identifiers declared (assigned) in this script
!    are reserved and required by data handler. 
! 2) New identifiers can be added, but attention must be
!    payed, that unique names are used.
!

[Const]
{
! Constants:
!
F=96487; !Faraday constant
R=8.31431; ! Universal gas constant
C0=1000*R/(F*2*100);
!
! Other corrections
Cref=1;
C=1;
!
! For Current caused by other oxidants
A0=0.0012250380415
A1=0.000124111475632
A2=-0.00000002687066130
!
! Query:
!
U1=?"Reference Voltage U1 (V):",1,10;
U2=?"Reference Voltage U2 (V):",1,10;
R1=?"Reference Resistance R1 (Ohm):",10000,900000;
R2=?"Reference Resistance R2 (Ohm):",10000,900000;
R3=?"Reference Resistance R3 (Ohm):",10000,900000;
K0=?"Compensation Factor K0 :",-0.1,0.1;
K1=?"Compensation Factor K1 :",-0.001,0.001;
K2=?"Compensation Factor K2 :",-0.0001,0.0001;
}

[Calibrate]
{
! 'vs' is For reduced ambient pressure at pump.
! Ozone partial pressure correction table reference number is
! given here. For example, if user gives value the 2,
! Data handler searhes for table [Solution-2] from Vaisala.ini
! The user can add new tables to Vaisala.ini.
!
! Predefined tables exist for  2.5ml and 3.0 ml solution
! (tables [Solution-1] and [Solution-2])
!
vs=?"Solution Volume (2.5ml = 1 , 3.0ml = 2): ",1,2;
fl=?"Flow Rate (s/100ml) :",1,100;
I0=?"Sensor Background Current (uA):",0,1;
P0=?"Calibration Pressure:",800,1200;
!
! Precalculate for IBG
CP0=(A0+A1*P0+A2*P0*P0);
}


[Init]
{
! Initialize some variables.  This is executed only once !
 U22 = U2;
 U11 = U1;
 Init=1;    ! Return value required
 AddData=0;
 AddData2=0;
}

[ThR]
{
! Calculate  thermistor resistance.
!
! Use previous values for U11, U22 
UT=U22*(S0-S7)/(S4-S7); ! U22*(R-REF2)/(REF1-REF2)
ThR=R1*R2*(U22-UT)/(R2*(U11+UT)+UT*R1);
!
! Note:
! This procedure is executed twice for every level (iteration)
! After evaluation of ThR the value for Tk is calculated by 
! internal support (by Data Handler) using interpolation and
! the table [Thermistor] in Vaisala.ini.
} 

[Tdr]
{
! Calculate temperature drift for voltage references
! Values U11 and U22 are stored for later use. ThR- procedure
! will use these to calculate thermistor resistance.
!
! Calculate new U11, U22 for next iteration of ThR.
!
Tdr=K0+K1*Tk+K2*Tk*Tk;
U22=U2+Tdr;
U11=U1+Tdr;
}

[I]
{
! Calculation of ozone sensor current
! Use U22 calculated in [Tdr]
! 
A=(U22/R3);
B=S4-S7; ! REF1 - REF2
!
! Sensors 1 .. 5
! Modify this to exclude sensors if required
!
I1=A*((S1-S7)/B); 
I2=A*((S2-S7)/B);
I3=A*((S3-S7)/B);
I4=A*((S5-S7)/B);
I5=A*((S6-S7)/B);
I=1000000*(I1+I2+I3+I4+I5)/5; ! In uA
}

[IBG]
{
! Current caused by other oxidants
!
IBG=I0*(A0+A1*P+A2*P*P)/CP0;
}

[Data]
{
! Finally, calculate the ozone value
!
 Tb=273.15+Tk; ! Appr. ozone box temperature in K
 Data=100*C0*(I-IBG)*Tb*fl*Cef*Cref*C; ! Use unit of 1/100 mPa 
}

[AddData]
{
! This group is required even if not used.
! Value < -100000 to AddData and AddData2 means "NOT USED"
!
! Internal identifiers used:
!    Edt     = current data value, same as "Data", but filtered
!    PrevEdt = previous data value
!    EdtP    = edited pressure (same as P, but filtered)
!    PrevEdtP= previous edited pressure
!
! For the integrated ozone (AddData) and residual ozone (AddData2):
!
!    e3=1.6571                  ratio of molar masses of ozone and air
!    M3=48.0          [g/mol]   molar mass of ozone
!    g =9.80665       [m/s2]    acceleration of gravity
!    NA=6.02217e+023  [1/mol]   Avogadro's constant
!    D=2.687e+20      [molecule/m2]
! Integrated ozone between pressures PrevEdtP and EdtP is given as
!
!    O3int=((e3 * NA)/g * M3 * D))*0.5*(Edt+PrevEdt)*ln(PrevEdtP/EdtP)
!
! in Dobson units when Edt and PrevEdt are given in mPa.
! Note: 
!    0.01 in the formulas is to convert Edt back to mPa
!    Symbol $ gives natural logarithm.
AddData2=7.8899*Edt*0.01;
AddData=AddData+(7.8899*(Edt+PrevEdt)/2)*$(PrevEdtP/EdtP)*0.01;
}