TMS320F28035: TMS320F28035 Lab5 example

I have a question on lab5 example located at "C:\ti\DPS Workshop_release v2\Workshop\DPS_Workshop\Lab5"

Can anybody tell me how Vref is calculated in this example. I see that it is calculated inside the function below but how/why:  Vout1SetSlewed is set to 2093568 , Vout2SlewRate is set to 25600.  

void A2(void)   // Slew Rate
//-----------------------------------------------------------------
{    
// This is an example code for implementing the slew rate control in
// a slower state machine instead of implementing it in the ISR.
// VoutXSlewRate should be set as a positive value
Vout1_slew_temp = Vref1 - Vout1SetSlewed;

if (Vout1_slew_temp >= Vout1SlewRate) // Positive Command
{
    Vout1SetSlewed = Vout1SetSlewed + Vout1SlewRate;
}
else
    {
    if ((-1)*(Vout1_slew_temp) >= Vout1SlewRate) // Negative Command
        {
        Vout1SetSlewed = Vout1SetSlewed - Vout1SlewRate;
        }
    else    Vout1SetSlewed = Vref1;
    }

Vout2_slew_temp = Vref2 - Vout2SetSlewed;

if (Vout2_slew_temp >= Vout2SlewRate) // Positive Command
{
    Vout2SetSlewed = Vout2SetSlewed + Vout2SlewRate;
}
else
    {
    if ((-1)*(Vout2_slew_temp) >= Vout2SlewRate) // Negative Command
        {
        Vout2SetSlewed = Vout2SetSlewed - Vout2SlewRate;
        }
    else    Vout2SetSlewed = Vref2;        
    }

    //-------------------
    //the next time CpuTimer0 'counter' reaches Period value go to A1
    A_Task_Ptr = &A3;
    //-------------------
}