You have to read about PID controllers but imho you should scale input from -32767..32767 to 0..32767.
Your analog output has less resolution then input so you can do it in this way.
In attachment i am sending example of using PID block.
Hi I tired the setup for temperature it does not stop at setup value rather than it goes on decreasing to negative if the output after sub function is ActualTemperature so i changed the value and checked there is no output from the PID the only thing i can see is the value is subtracted on every cycle by 0.1.
Can you please explain the working