Movement of objects

My intention is to move an elevator upwards and downwards. I want that the object moves according to an analogical variable (which I obtain from a micromasters), slowly in the first, with constant speed in half and slowly in the end.
I have tried different actions in c but no works correctly.

A piece of the code that I have done

int Frec;
int posY;

Frec=GetTagWord("EW130");
posY=400;

if (Frec<=1)
{
(posY=posY);
return posY;
}

if (Frec>2){
if (Frec<10){

(posY=posY-15);
return (posY);
}
}

if (Frec>11){
if (Frec<20){

(posY=posY-30);
return (posY);
}
}

if (Frec>21){
if (Frec<30){

(posY=posY-45);
return (posY);
}
}

if (Frec>31){
if (Frec<40){

(posY=posY-60);
return (posY);
}
}

if (Frec>41){
if (Frec<50){

(posY=posY-75);
return (posY);
}
}

With this code the objet moves a little but later the object return to the initial position.