The first part looks like an integral part as I = I + P where I is your integral term and P is a proportional term (setpoint - feedback * Pgain). The P and I parts look like Dints and following the calculation the result is divided by 10000 and stored as an int (W15G1MF3). I don't fully understand what is shown after the integral term but I'm guessing that it is the derivative part and it looks like there is a switch to disable the D part.
I've never seen a language like that before.
Nick